From efd4119054aaa003ffca8f6e33579fb4a4b1b441 Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Fri, 10 May 2024 14:18:10 -0400
Subject: [PATCH 01/18] sigstore: refactor trust state management

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 sigstore/_cli.py                              | 114 +++---------------
 sigstore/_internal/{trustroot.py => trust.py} |   0
 2 files changed, 16 insertions(+), 98 deletions(-)
 rename sigstore/_internal/{trustroot.py => trust.py} (100%)

diff --git a/sigstore/_cli.py b/sigstore/_cli.py
index 1835bc299..da473ea8c 100644
--- a/sigstore/_cli.py
+++ b/sigstore/_cli.py
@@ -27,17 +27,8 @@
 from rich.logging import RichHandler
 
 from sigstore import __version__
-from sigstore._internal.fulcio.client import (
-    DEFAULT_FULCIO_URL,
-    ExpiredCertificate,
-    FulcioClient,
-)
+from sigstore._internal.fulcio.client import ExpiredCertificate
 from sigstore._internal.rekor import _hashedrekord_from_parts
-from sigstore._internal.rekor.client import (
-    DEFAULT_REKOR_URL,
-    RekorClient,
-)
-from sigstore._internal.trustroot import KeyringPurpose, TrustedRoot
 from sigstore._utils import sha256_digest
 from sigstore.errors import Error, VerificationError
 from sigstore.hashes import Hashed
@@ -95,35 +86,6 @@ def _boolify_env(envvar: str) -> bool:
         raise ValueError(f"can't coerce '{val}' to a boolean")
 
 
-def _add_shared_instance_options(group: argparse._ArgumentGroup) -> None:
-    """
-    Common Sigstore instance options, shared between all `sigstore` subcommands.
-    """
-    group.add_argument(
-        "--staging",
-        dest="__deprecated_staging",
-        action="store_true",
-        default=False,
-        help=(
-            "Use sigstore's staging instances, instead of the default production instances. "
-            "This option will be deprecated in favor of the global `--staging` option "
-            "in a future release."
-        ),
-    )
-    group.add_argument(
-        "--rekor-url",
-        dest="__deprecated_rekor_url",
-        metavar="URL",
-        type=str,
-        default=None,
-        help=(
-            "The Rekor instance to use (conflicts with --staging). "
-            "This option will be deprecated in favor of the global `--rekor-url` option "
-            "in a future release."
-        ),
-    )
-
-
 def _add_shared_verify_input_options(group: argparse._ArgumentGroup) -> None:
     """
     Common input options, shared between all `sigstore verify` subcommands.
@@ -238,7 +200,7 @@ def _parser() -> argparse.ArgumentParser:
         "-V", "--version", action="version", version=f"sigstore {__version__}"
     )
 
-    global_instance_options = parser.add_argument_group("Sigstore instance options")
+    global_instance_options = parser.add_mutually_exclusive_group()
     global_instance_options.add_argument(
         "--staging",
         action="store_true",
@@ -246,13 +208,11 @@ def _parser() -> argparse.ArgumentParser:
         help="Use sigstore's staging instances, instead of the default production instances",
     )
     global_instance_options.add_argument(
-        "--rekor-url",
-        metavar="URL",
+        "--trust-config",
+        metavar="FILE",
         type=str,
-        default=os.getenv("SIGSTORE_REKOR_URL", DEFAULT_REKOR_URL),
-        help="The Rekor instance to use (conflicts with --staging)",
+        help="The client trust configuration to use",
     )
-
     subcommands = parser.add_subparsers(
         required=True,
         dest="subcommand",
@@ -332,16 +292,6 @@ def _parser() -> argparse.ArgumentParser:
         help="Overwrite preexisting signature and certificate outputs, if present",
     )
 
-    instance_options = sign.add_argument_group("Sigstore instance options")
-    _add_shared_instance_options(instance_options)
-    instance_options.add_argument(
-        "--fulcio-url",
-        metavar="URL",
-        type=str,
-        default=os.getenv("SIGSTORE_FULCIO_URL", DEFAULT_FULCIO_URL),
-        help="The Fulcio instance to use (conflicts with --staging)",
-    )
-
     sign.add_argument(
         "files",
         metavar="FILE",
@@ -385,9 +335,6 @@ def _parser() -> argparse.ArgumentParser:
         required=True,
     )
 
-    instance_options = verify_identity.add_argument_group("Sigstore instance options")
-    _add_shared_instance_options(instance_options)
-
     # `sigstore verify github`
     verify_github = verify_subcommand.add_parser(
         "github",
@@ -442,9 +389,6 @@ def _parser() -> argparse.ArgumentParser:
         help="The `git` ref that the workflow was invoked with",
     )
 
-    instance_options = verify_github.add_argument_group("Sigstore instance options")
-    _add_shared_instance_options(instance_options)
-
     # `sigstore get-identity-token`
     get_identity_token = subcommands.add_parser(
         "get-identity-token",
@@ -469,22 +413,6 @@ def main() -> None:
 
     _logger.debug(f"parsed arguments {args}")
 
-    # A few instance flags (like `--staging` and `--rekor-url`) are supported at both the
-    # top-level `sigstore` level and the subcommand level (e.g. `sigstore verify --staging`),
-    # but the former is preferred.
-    if getattr(args, "__deprecated_staging", False):
-        _logger.warning(
-            "`--staging` should be used as a global option, rather than a subcommand option. "
-            "Passing `--staging` as a subcommand option will be deprecated in a future release."
-        )
-        args.staging = args.__deprecated_staging
-    if getattr(args, "__deprecated_rekor_url", None):
-        _logger.warning(
-            "`--rekor-url` should be used as a global option, rather than a subcommand option. "
-            "Passing `--rekor-url` as a subcommand option will be deprecated in a future release."
-        )
-        args.rekor_url = args.__deprecated_rekor_url
-
     # Stuff the parser back into our namespace, so that we can use it for
     # error handling later.
     args._parser = parser
@@ -588,17 +516,13 @@ def _sign(args: argparse.Namespace) -> None:
         _logger.debug("sign: staging instances requested")
         signing_ctx = SigningContext.staging()
         args.oidc_issuer = STAGING_OAUTH_ISSUER_URL
-    elif args.fulcio_url == DEFAULT_FULCIO_URL and args.rekor_url == DEFAULT_REKOR_URL:
-        signing_ctx = SigningContext.production()
+    elif args.trust_config:
+        raise ValueError("fuck")
     else:
-        # Assume "production" trust root if no keys are given as arguments
-        trusted_root = TrustedRoot.production(purpose=KeyringPurpose.SIGN)
-
-        signing_ctx = SigningContext(
-            fulcio=FulcioClient(args.fulcio_url),
-            rekor=RekorClient(args.rekor_url),
-            trusted_root=trusted_root,
-        )
+        # If the user didn't request the staging instance or pass in an
+        # explicit client trust config, we're using the public good (i.e.
+        # production) instance.
+        signing_ctx = SigningContext.production()
 
     # The order of precedence for identities is as follows:
     #
@@ -738,8 +662,8 @@ def _collect_verification_state(
                 missing.append(str(cert))
             input_map[file] = {"cert": cert, "sig": sig}
         else:
-            # If a user hasn't explicitly supplied `--signature`, `--certificate` or
-            # `--rekor-bundle`, we expect a bundle either supplied via `--bundle` or with the
+            # If a user hasn't explicitly supplied `--signature` or `--certificate`,
+            # we expect a bundle either supplied via `--bundle` or with the
             # default `{input}.sigstore(.json)?` name.
             if not bundle.is_file():
                 missing.append(str(bundle))
@@ -754,16 +678,10 @@ def _collect_verification_state(
     if args.staging:
         _logger.debug("verify: staging instances requested")
         verifier = Verifier.staging()
-    elif args.rekor_url == DEFAULT_REKOR_URL:
-        verifier = Verifier.production()
+    elif args.trust_config:
+        raise ValueError("fuck")
     else:
-        trusted_root = TrustedRoot.production(purpose=KeyringPurpose.VERIFY)
-        verifier = Verifier(
-            rekor=RekorClient(
-                url=args.rekor_url,
-            ),
-            trusted_root=trusted_root,
-        )
+        verifier = Verifier.production()
 
     all_materials = []
     for file, inputs in input_map.items():
diff --git a/sigstore/_internal/trustroot.py b/sigstore/_internal/trust.py
similarity index 100%
rename from sigstore/_internal/trustroot.py
rename to sigstore/_internal/trust.py

From b94888b46eb1c33d3ee522f88a4a551d7687d7be Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Fri, 10 May 2024 14:18:49 -0400
Subject: [PATCH 02/18] test: rename

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 test/unit/internal/{test_trust_root.py => test_trust.py} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename test/unit/internal/{test_trust_root.py => test_trust.py} (100%)

diff --git a/test/unit/internal/test_trust_root.py b/test/unit/internal/test_trust.py
similarity index 100%
rename from test/unit/internal/test_trust_root.py
rename to test/unit/internal/test_trust.py

From e5d24b05d9de7895f76109a1b95189c4221181b6 Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Fri, 10 May 2024 14:19:13 -0400
Subject: [PATCH 03/18] docstring

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 sigstore/_internal/trust.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sigstore/_internal/trust.py b/sigstore/_internal/trust.py
index 8b60b263b..6dca56b56 100644
--- a/sigstore/_internal/trust.py
+++ b/sigstore/_internal/trust.py
@@ -13,7 +13,7 @@
 # limitations under the License.
 
 """
-Trust root management for sigstore-python.
+Client trust configuration and trust root management for sigstore-python.
 """
 
 from __future__ import annotations

From 0be13aae77aaa9696e8c9afe572527a5b17401eb Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Fri, 10 May 2024 14:25:58 -0400
Subject: [PATCH 04/18] sigstore, test: propagate rename

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 sigstore/_internal/rekor/checkpoint.py | 2 +-
 sigstore/_internal/sct.py              | 2 +-
 sigstore/models.py                     | 2 +-
 sigstore/sign.py                       | 2 +-
 sigstore/verify/verifier.py            | 2 +-
 test/unit/internal/test_trust.py       | 2 +-
 6 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/sigstore/_internal/rekor/checkpoint.py b/sigstore/_internal/rekor/checkpoint.py
index c49ae67b9..a02c3cbb2 100644
--- a/sigstore/_internal/rekor/checkpoint.py
+++ b/sigstore/_internal/rekor/checkpoint.py
@@ -27,7 +27,7 @@
 
 from pydantic import BaseModel, Field, StrictStr
 
-from sigstore._internal.trustroot import RekorKeyring
+from sigstore._internal.trust import RekorKeyring
 from sigstore._utils import KeyID
 from sigstore.errors import VerificationError
 
diff --git a/sigstore/_internal/sct.py b/sigstore/_internal/sct.py
index 8a6a943f7..e9ad5a45f 100644
--- a/sigstore/_internal/sct.py
+++ b/sigstore/_internal/sct.py
@@ -35,7 +35,7 @@
 )
 from cryptography.x509.oid import ExtendedKeyUsageOID
 
-from sigstore._internal.trustroot import CTKeyring
+from sigstore._internal.trust import CTKeyring
 from sigstore._utils import (
     DERCert,
     KeyID,
diff --git a/sigstore/models.py b/sigstore/models.py
index cb7f60257..7b03cc537 100644
--- a/sigstore/models.py
+++ b/sigstore/models.py
@@ -65,7 +65,7 @@
 from sigstore.errors import Error, VerificationError
 
 if typing.TYPE_CHECKING:
-    from sigstore._internal.trustroot import RekorKeyring
+    from sigstore._internal.trust import RekorKeyring
 
 
 _logger = logging.getLogger(__name__)
diff --git a/sigstore/sign.py b/sigstore/sign.py
index d7d3a21f6..e95981e58 100644
--- a/sigstore/sign.py
+++ b/sigstore/sign.py
@@ -62,7 +62,7 @@
 )
 from sigstore._internal.rekor.client import RekorClient
 from sigstore._internal.sct import verify_sct
-from sigstore._internal.trustroot import KeyringPurpose, TrustedRoot
+from sigstore._internal.trust import KeyringPurpose, TrustedRoot
 from sigstore._utils import sha256_digest
 from sigstore.models import Bundle
 from sigstore.oidc import ExpiredIdentity, IdentityToken
diff --git a/sigstore/verify/verifier.py b/sigstore/verify/verifier.py
index bdf48b387..d7944acff 100644
--- a/sigstore/verify/verifier.py
+++ b/sigstore/verify/verifier.py
@@ -44,7 +44,7 @@
     _get_precertificate_signed_certificate_timestamps,
     verify_sct,
 )
-from sigstore._internal.trustroot import KeyringPurpose, TrustedRoot
+from sigstore._internal.trust import KeyringPurpose, TrustedRoot
 from sigstore._utils import base64_encode_pem_cert, sha256_digest
 from sigstore.errors import VerificationError
 from sigstore.hashes import Hashed
diff --git a/test/unit/internal/test_trust.py b/test/unit/internal/test_trust.py
index 0cc4cab64..a69cbdd0b 100644
--- a/test/unit/internal/test_trust.py
+++ b/test/unit/internal/test_trust.py
@@ -21,7 +21,7 @@
 from cryptography.x509 import load_pem_x509_certificate
 from sigstore_protobuf_specs.dev.sigstore.common.v1 import TimeRange
 
-from sigstore._internal.trustroot import (
+from sigstore._internal.trust import (
     KeyringPurpose,
     TrustedRoot,
     _is_timerange_valid,

From 172fc0e3b8be468629838233d9b1752fa418212e Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Fri, 10 May 2024 15:55:20 -0400
Subject: [PATCH 05/18] _internal: hackety hack

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 sigstore/_internal/trust.py | 37 ++++++++++++++++++++++++++++++++-----
 1 file changed, 32 insertions(+), 5 deletions(-)

diff --git a/sigstore/_internal/trust.py b/sigstore/_internal/trust.py
index 6dca56b56..3e029bccf 100644
--- a/sigstore/_internal/trust.py
+++ b/sigstore/_internal/trust.py
@@ -41,6 +41,9 @@
     CertificateAuthority,
     TransparencyLogInstance,
 )
+from sigstore_protobuf_specs.dev.sigstore.trustroot.v1 import (
+    ClientTrustConfig as _ClientTrustConfig,
+)
 from sigstore_protobuf_specs.dev.sigstore.trustroot.v1 import (
     TrustedRoot as _TrustedRoot,
 )
@@ -266,15 +269,14 @@ def staging(
         """
         return cls.from_tuf(STAGING_TUF_URL, offline, purpose)
 
-    @staticmethod
     def _get_tlog_keys(
-        tlogs: list[TransparencyLogInstance], purpose: KeyringPurpose
+        self, tlogs: list[TransparencyLogInstance]
     ) -> Iterable[_PublicKey]:
         """
         Yields an iterator of public keys for transparency log instances that
         are suitable for `purpose`.
         """
-        allow_expired = purpose is KeyringPurpose.VERIFY
+        allow_expired = self.purpose is KeyringPurpose.VERIFY
         for tlog in tlogs:
             if not _is_timerange_valid(
                 tlog.public_key.valid_for, allow_expired=allow_expired
@@ -298,14 +300,14 @@ def _get_ca_keys(
     def rekor_keyring(self) -> RekorKeyring:
         """Return keyring with keys for Rekor."""
 
-        keys: list[_PublicKey] = list(self._get_tlog_keys(self.tlogs, self.purpose))
+        keys: list[_PublicKey] = list(self._get_tlog_keys(self.tlogs))
         if len(keys) != 1:
             raise MetadataError("Did not find one Rekor key in trusted root")
         return RekorKeyring(Keyring(keys))
 
     def ct_keyring(self) -> CTKeyring:
         """Return keyring with key for CTFE."""
-        ctfes: list[_PublicKey] = list(self._get_tlog_keys(self.ctlogs, self.purpose))
+        ctfes: list[_PublicKey] = list(self._get_tlog_keys(self.ctlogs))
         if not ctfes:
             raise MetadataError("CTFE keys not found in trusted root")
         return CTKeyring(Keyring(ctfes))
@@ -324,3 +326,28 @@ def get_fulcio_certs(self) -> list[Certificate]:
         if not certs:
             raise MetadataError("Fulcio certificates not found in trusted root")
         return certs
+
+
+class ClientTrustConfig:
+    """
+    Represents a Sigstore client's trust configuration, including a root of trust.
+    """
+
+    @classmethod
+    def from_json(cls, raw: str) -> None:
+        """
+        Deserialize the given client trust config.
+        """
+        inner = _ClientTrustConfig().from_json(raw)
+        cls(inner)
+
+    def __init__(self, inner: _ClientTrustConfig) -> None:
+        """
+        @api private
+        """
+        self._inner = inner
+        # self._
+
+    # @property
+    # def trusted_root(self) -> TrustedRoot:
+    #     pass

From 89990947b234668110c4ce90dd59bc7b39dc4429 Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Tue, 14 May 2024 16:17:12 -0400
Subject: [PATCH 06/18] sigstore: refactor purpose handling

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 sigstore/_internal/trust.py | 40 ++++++++++++++++++-------------------
 sigstore/sign.py            | 19 +++++++++++-------
 sigstore/verify/verifier.py | 10 ++++------
 3 files changed, 36 insertions(+), 33 deletions(-)

diff --git a/sigstore/_internal/trust.py b/sigstore/_internal/trust.py
index ad18de3ad..c879c03eb 100644
--- a/sigstore/_internal/trust.py
+++ b/sigstore/_internal/trust.py
@@ -217,28 +217,28 @@ def __str__(self) -> str:
         return self.value
 
 
-class TrustedRoot(_TrustedRoot):
-    """Complete set of trusted entities for a Sigstore client"""
+class TrustedRoot:
+    """
+    The cryptographic root(s) of trust for a Sigstore instance.
+    """
 
-    purpose: KeyringPurpose
+    def __init__(self, inner: _TrustedRoot):
+        self._inner = inner
 
     @classmethod
     def from_file(
         cls,
         path: str,
-        purpose: KeyringPurpose = KeyringPurpose.VERIFY,
     ) -> TrustedRoot:
         """Create a new trust root from file"""
-        trusted_root: TrustedRoot = cls().from_json(Path(path).read_bytes())
-        trusted_root.purpose = purpose
-        return trusted_root
+        inner = _TrustedRoot().from_json(Path(path).read_bytes())
+        return cls(inner)
 
     @classmethod
     def from_tuf(
         cls,
         url: str,
         offline: bool = False,
-        purpose: KeyringPurpose = KeyringPurpose.VERIFY,
     ) -> TrustedRoot:
         """Create a new trust root from a TUF repository.
 
@@ -246,42 +246,40 @@ def from_tuf(
         update the trust root from remote TUF repository.
         """
         path = TrustUpdater(url, offline).get_trusted_root_path()
-        return cls.from_file(path, purpose)
+        return cls.from_file(path)
 
     @classmethod
     def production(
         cls,
         offline: bool = False,
-        purpose: KeyringPurpose = KeyringPurpose.VERIFY,
     ) -> TrustedRoot:
         """Create new trust root from Sigstore production TUF repository.
 
         If `offline`, will use trust root in local TUF cache. Otherwise will
         update the trust root from remote TUF repository.
         """
-        return cls.from_tuf(DEFAULT_TUF_URL, offline, purpose)
+        return cls.from_tuf(DEFAULT_TUF_URL, offline)
 
     @classmethod
     def staging(
         cls,
         offline: bool = False,
-        purpose: KeyringPurpose = KeyringPurpose.VERIFY,
     ) -> TrustedRoot:
         """Create new trust root from Sigstore staging TUF repository.
 
         If `offline`, will use trust root in local TUF cache. Otherwise will
         update the trust root from remote TUF repository.
         """
-        return cls.from_tuf(STAGING_TUF_URL, offline, purpose)
+        return cls.from_tuf(STAGING_TUF_URL, offline)
 
     def _get_tlog_keys(
-        self, tlogs: list[TransparencyLogInstance]
+        self, tlogs: list[TransparencyLogInstance], purpose: KeyringPurpose
     ) -> Iterable[_PublicKey]:
         """
         Yields an iterator of public keys for transparency log instances that
         are suitable for `purpose`.
         """
-        allow_expired = self.purpose is KeyringPurpose.VERIFY
+        allow_expired = purpose is KeyringPurpose.VERIFY
         for tlog in tlogs:
             if not _is_timerange_valid(
                 tlog.public_key.valid_for, allow_expired=allow_expired
@@ -302,17 +300,17 @@ def _get_ca_keys(
             for cert in ca.cert_chain.certificates:
                 yield cert.raw_bytes
 
-    def rekor_keyring(self) -> RekorKeyring:
+    def rekor_keyring(self, purpose: KeyringPurpose) -> RekorKeyring:
         """Return keyring with keys for Rekor."""
 
-        keys: list[_PublicKey] = list(self._get_tlog_keys(self.tlogs))
+        keys: list[_PublicKey] = list(self._get_tlog_keys(self._inner.tlogs, purpose))
         if len(keys) != 1:
             raise MetadataError("Did not find one Rekor key in trusted root")
         return RekorKeyring(Keyring(keys))
 
-    def ct_keyring(self) -> CTKeyring:
+    def ct_keyring(self, purpose: KeyringPurpose) -> CTKeyring:
         """Return keyring with key for CTFE."""
-        ctfes: list[_PublicKey] = list(self._get_tlog_keys(self.ctlogs))
+        ctfes: list[_PublicKey] = list(self._get_tlog_keys(self._inner.ctlogs, purpose))
         if not ctfes:
             raise MetadataError("CTFE keys not found in trusted root")
         return CTKeyring(Keyring(ctfes))
@@ -326,7 +324,9 @@ def get_fulcio_certs(self) -> list[Certificate]:
         # been active when the certificate was used to sign.
         certs = [
             load_der_x509_certificate(c)
-            for c in self._get_ca_keys(self.certificate_authorities, allow_expired=True)
+            for c in self._get_ca_keys(
+                self._inner.certificate_authorities, allow_expired=True
+            )
         ]
         if not certs:
             raise MetadataError("Fulcio certificates not found in trusted root")
diff --git a/sigstore/sign.py b/sigstore/sign.py
index e95981e58..1c59d345b 100644
--- a/sigstore/sign.py
+++ b/sigstore/sign.py
@@ -165,7 +165,12 @@ def _signing_cert(
             cert = certificate_response.cert
             chain = certificate_response.chain
 
-            verify_sct(sct, cert, chain, self._signing_ctx._trusted_root.ct_keyring())
+            verify_sct(
+                sct,
+                cert,
+                chain,
+                self._signing_ctx._trusted_root.ct_keyring(KeyringPurpose.SIGN),
+            )
 
             _logger.debug("Successfully verified SCT...")
 
@@ -311,10 +316,10 @@ def production(cls) -> SigningContext:
         """
         Return a `SigningContext` instance configured against Sigstore's production-level services.
         """
-        trusted_root = TrustedRoot.production(purpose=KeyringPurpose.SIGN)
-        rekor = RekorClient.production()
         return cls(
-            fulcio=FulcioClient.production(), rekor=rekor, trusted_root=trusted_root
+            fulcio=FulcioClient.production(),
+            rekor=RekorClient.production(),
+            trusted_root=TrustedRoot.production(),
         )
 
     @classmethod
@@ -322,10 +327,10 @@ def staging(cls) -> SigningContext:
         """
         Return a `SignerContext` instance configured against Sigstore's staging-level services.
         """
-        trusted_root = TrustedRoot.staging(purpose=KeyringPurpose.SIGN)
-        rekor = RekorClient.staging()
         return cls(
-            fulcio=FulcioClient.staging(), rekor=rekor, trusted_root=trusted_root
+            fulcio=FulcioClient.staging(),
+            rekor=RekorClient.staging(),
+            trusted_root=TrustedRoot.staging(),
         )
 
     @contextmanager
diff --git a/sigstore/verify/verifier.py b/sigstore/verify/verifier.py
index d7944acff..278a57a19 100644
--- a/sigstore/verify/verifier.py
+++ b/sigstore/verify/verifier.py
@@ -81,10 +81,9 @@ def production(cls) -> Verifier:
         """
         Return a `Verifier` instance configured against Sigstore's production-level services.
         """
-        trusted_root = TrustedRoot.production(purpose=KeyringPurpose.VERIFY)
         return cls(
             rekor=RekorClient.production(),
-            trusted_root=trusted_root,
+            trusted_root=TrustedRoot.production(),
         )
 
     @classmethod
@@ -92,10 +91,9 @@ def staging(cls) -> Verifier:
         """
         Return a `Verifier` instance configured against Sigstore's staging-level services.
         """
-        trusted_root = TrustedRoot.staging(purpose=KeyringPurpose.VERIFY)
         return cls(
             rekor=RekorClient.staging(),
-            trusted_root=trusted_root,
+            trusted_root=TrustedRoot.staging(),
         )
 
     def _verify_common_signing_cert(
@@ -166,7 +164,7 @@ def _verify_common_signing_cert(
                 sct,
                 cert,
                 [parent_cert.to_cryptography() for parent_cert in chain],
-                self._trusted_root.ct_keyring(),
+                self._trusted_root.ct_keyring(KeyringPurpose.VERIFY),
             )
         except VerificationError as e:
             raise VerificationError(f"failed to verify SCT on signing certificate: {e}")
@@ -190,7 +188,7 @@ def _verify_common_signing_cert(
         # (5): verify the inclusion promise for the log entry, if present.
         entry = bundle.log_entry
         try:
-            entry._verify(self._trusted_root.rekor_keyring())
+            entry._verify(self._trusted_root.rekor_keyring(KeyringPurpose.VERIFY))
         except VerificationError as exc:
             raise VerificationError(f"invalid log entry: {exc}")
 

From fa05d2708e0cb9c8161615811e293da68bf64351 Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Tue, 14 May 2024 16:27:51 -0400
Subject: [PATCH 07/18] trust: docstring

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 sigstore/_internal/trust.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sigstore/_internal/trust.py b/sigstore/_internal/trust.py
index c879c03eb..77801cf90 100644
--- a/sigstore/_internal/trust.py
+++ b/sigstore/_internal/trust.py
@@ -223,6 +223,11 @@ class TrustedRoot:
     """
 
     def __init__(self, inner: _TrustedRoot):
+        """
+        Construct a new `TrustedRoot`.
+
+        @api private
+        """
         self._inner = inner
 
     @classmethod

From a1c0784aa9f38699c6cbcff38eb27e6de60d711e Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Tue, 14 May 2024 16:36:08 -0400
Subject: [PATCH 08/18] fixup trust tests

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 test/unit/internal/test_trust.py | 78 +++++++++++++++++++++++---------
 1 file changed, 57 insertions(+), 21 deletions(-)

diff --git a/test/unit/internal/test_trust.py b/test/unit/internal/test_trust.py
index a69cbdd0b..cc55c8fcf 100644
--- a/test/unit/internal/test_trust.py
+++ b/test/unit/internal/test_trust.py
@@ -37,7 +37,7 @@ def test_trust_root_tuf_caches_and_requests(mock_staging_tuf, tuf_dirs):
     # keep track of requests the TrustUpdater invoked by TrustedRoot makes
     reqs, fail_reqs = mock_staging_tuf
 
-    trust_root = TrustedRoot.staging(purpose=KeyringPurpose.VERIFY)
+    trust_root = TrustedRoot.staging()
     # metadata was "downloaded" from staging
     expected = ["root.json", "snapshot.json", "targets.json", "timestamp.json"]
     assert sorted(os.listdir(data_dir)) == expected
@@ -53,15 +53,15 @@ def test_trust_root_tuf_caches_and_requests(mock_staging_tuf, tuf_dirs):
     assert reqs == expected_requests
     assert fail_reqs == expected_fail_reqs
 
-    trust_root.ct_keyring()
-    trust_root.rekor_keyring()
+    trust_root.ct_keyring(KeyringPurpose.VERIFY)
+    trust_root.rekor_keyring(KeyringPurpose.VERIFY)
 
     # no new requests
     assert reqs == expected_requests
     assert fail_reqs == expected_fail_reqs
 
     # New trust root (and TrustUpdater instance), same cache dirs
-    trust_root = TrustedRoot.staging(purpose=KeyringPurpose.VERIFY)
+    trust_root = TrustedRoot.staging()
 
     # Expect new timestamp and root requests
     expected_requests["timestamp.json"] += 1
@@ -69,8 +69,8 @@ def test_trust_root_tuf_caches_and_requests(mock_staging_tuf, tuf_dirs):
     assert reqs == expected_requests
     assert fail_reqs == expected_fail_reqs
 
-    trust_root.ct_keyring()
-    trust_root.rekor_keyring()
+    trust_root.ct_keyring(purpose=KeyringPurpose.VERIFY)
+    trust_root.rekor_keyring(purpose=KeyringPurpose.VERIFY)
     # Expect no requests
     assert reqs == expected_requests
     assert fail_reqs == expected_fail_reqs
@@ -83,7 +83,7 @@ def test_trust_root_tuf_offline(mock_staging_tuf, tuf_dirs):
     # keep track of requests the TrustUpdater invoked by TrustedRoot makes
     reqs, fail_reqs = mock_staging_tuf
 
-    trust_root = TrustedRoot.staging(offline=True, purpose=KeyringPurpose.VERIFY)
+    trust_root = TrustedRoot.staging(offline=True)
 
     # Only the embedded root is in local TUF metadata, nothing is downloaded
     expected = ["root.json"]
@@ -91,8 +91,8 @@ def test_trust_root_tuf_offline(mock_staging_tuf, tuf_dirs):
     assert reqs == {}
     assert fail_reqs == {}
 
-    trust_root.ct_keyring()
-    trust_root.rekor_keyring()
+    trust_root.ct_keyring(purpose=KeyringPurpose.VERIFY)
+    trust_root.rekor_keyring(purpose=KeyringPurpose.VERIFY)
 
     # Still no requests
     assert reqs == {}
@@ -153,35 +153,71 @@ def _pem_keys(keys):
     ]
 
     # Assert that trust root from TUF contains the expected keys/certs
-    trust_root = TrustedRoot.staging(purpose=KeyringPurpose.VERIFY)
+    trust_root = TrustedRoot.staging()
     assert ctfe_keys[0] in get_public_bytes(
-        [k.key for k in trust_root.ct_keyring()._keyring.values()]
+        [
+            k.key
+            for k in trust_root.ct_keyring(
+                purpose=KeyringPurpose.VERIFY
+            )._keyring.values()
+        ]
     )
     assert (
-        get_public_bytes([k.key for k in trust_root.rekor_keyring()._keyring.values()])
+        get_public_bytes(
+            [
+                k.key
+                for k in trust_root.rekor_keyring(
+                    purpose=KeyringPurpose.VERIFY
+                )._keyring.values()
+            ]
+        )
         == rekor_keys
     )
     assert trust_root.get_fulcio_certs() == fulcio_certs
 
     # Assert that trust root from offline TUF contains the expected keys/certs
-    trust_root = TrustedRoot.staging(offline=True, purpose=KeyringPurpose.VERIFY)
+    trust_root = TrustedRoot.staging(offline=True)
     assert ctfe_keys[0] in get_public_bytes(
-        [k.key for k in trust_root.ct_keyring()._keyring.values()]
+        [
+            k.key
+            for k in trust_root.ct_keyring(
+                purpose=KeyringPurpose.VERIFY
+            )._keyring.values()
+        ]
     )
     assert (
-        get_public_bytes([k.key for k in trust_root.rekor_keyring()._keyring.values()])
+        get_public_bytes(
+            [
+                k.key
+                for k in trust_root.rekor_keyring(
+                    purpose=KeyringPurpose.VERIFY
+                )._keyring.values()
+            ]
+        )
         == rekor_keys
     )
     assert trust_root.get_fulcio_certs() == fulcio_certs
 
     # Assert that trust root from file contains the expected keys/certs
     path = tuf_asset.target_path("trusted_root.json")
-    trust_root = TrustedRoot.from_file(path, purpose=KeyringPurpose.VERIFY)
+    trust_root = TrustedRoot.from_file(path)
     assert ctfe_keys[0] in get_public_bytes(
-        [k.key for k in trust_root.ct_keyring()._keyring.values()]
+        [
+            k.key
+            for k in trust_root.ct_keyring(
+                purpose=KeyringPurpose.VERIFY
+            )._keyring.values()
+        ]
     )
     assert (
-        get_public_bytes([k.key for k in trust_root.rekor_keyring()._keyring.values()])
+        get_public_bytes(
+            [
+                k.key
+                for k in trust_root.rekor_keyring(
+                    purpose=KeyringPurpose.VERIFY
+                )._keyring.values()
+            ]
+        )
         == rekor_keys
     )
     assert trust_root.get_fulcio_certs() == fulcio_certs
@@ -194,14 +230,14 @@ def test_trust_root_tuf_instance_error():
 
 def test_trust_root_tuf_ctfe_keys_error(monkeypatch):
     trust_root = TrustedRoot.staging(offline=True)
-    monkeypatch.setattr(trust_root, "ctlogs", [])
+    monkeypatch.setattr(trust_root._inner, "ctlogs", [])
     with pytest.raises(Exception, match="CTFE keys not found in trusted root"):
-        trust_root.ct_keyring()
+        trust_root.ct_keyring(purpose=KeyringPurpose.VERIFY)
 
 
 def test_trust_root_fulcio_certs_error(tuf_asset, monkeypatch):
     trust_root = TrustedRoot.staging(offline=True)
-    monkeypatch.setattr(trust_root, "certificate_authorities", [])
+    monkeypatch.setattr(trust_root._inner, "certificate_authorities", [])
     with pytest.raises(
         Exception, match="Fulcio certificates not found in trusted root"
     ):

From 239397a6068dac0645305b92ea0f4b37d219e4a9 Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Tue, 14 May 2024 16:42:49 -0400
Subject: [PATCH 09/18] test_sign: fixup

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 test/unit/test_sign.py | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/test/unit/test_sign.py b/test/unit/test_sign.py
index 233340eaf..5c2e2a496 100644
--- a/test/unit/test_sign.py
+++ b/test/unit/test_sign.py
@@ -66,7 +66,7 @@ def test_sct_verify_keyring_lookup_error(sign_ctx_and_ident_for_env, monkeypatch
     # a signer whose keyring always fails to lookup a given key.
     ctx: SigningContext = ctx()
     mock = pretend.stub(
-        ct_keyring=lambda: pretend.stub(verify=pretend.raiser(VerificationError))
+        ct_keyring=lambda *a: pretend.stub(verify=pretend.raiser(VerificationError))
     )
     ctx._trusted_root = mock
     assert identity is not None
@@ -85,10 +85,9 @@ def test_sct_verify_keyring_error(sign_ctx_and_ident_for_env, monkeypatch):
     # a signer whose keyring throws an internal error.
     ctx: SigningContext = ctx()
     mock = pretend.stub(
-        ct_keyring=lambda: pretend.stub(verify=pretend.raiser(VerificationError))
+        ct_keyring=lambda *a: pretend.stub(verify=pretend.raiser(VerificationError))
     )
     ctx._trusted_root = mock
-    ctx._rekor._ct_keyring = pretend.stub(verify=pretend.raiser(VerificationError))
     assert identity is not None
 
     payload = secrets.token_bytes(32)

From 5c6b4f19ce6c1ec6fa865290f031ee6121d6f0f3 Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Tue, 14 May 2024 16:59:53 -0400
Subject: [PATCH 10/18] hook up client trust config

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 sigstore/_cli.py            | 11 ++++++-----
 sigstore/_internal/trust.py | 14 ++++++++------
 sigstore/sign.py            | 15 ++++++++++++++-
 sigstore/verify/verifier.py | 14 +++++++++++++-
 4 files changed, 41 insertions(+), 13 deletions(-)

diff --git a/sigstore/_cli.py b/sigstore/_cli.py
index c9cb8b684..9b9e8fa1e 100644
--- a/sigstore/_cli.py
+++ b/sigstore/_cli.py
@@ -29,13 +29,13 @@
 from sigstore import __version__
 from sigstore._internal.fulcio.client import ExpiredCertificate
 from sigstore._internal.rekor import _hashedrekord_from_parts
+from sigstore._internal.trust import ClientTrustConfig
 from sigstore._utils import sha256_digest
 from sigstore.errors import Error, VerificationError
 from sigstore.hashes import Hashed
 from sigstore.models import Bundle
 from sigstore.oidc import (
     DEFAULT_OAUTH_ISSUER_URL,
-    STAGING_OAUTH_ISSUER_URL,
     ExpiredIdentity,
     IdentityToken,
     Issuer,
@@ -210,7 +210,7 @@ def _parser() -> argparse.ArgumentParser:
     global_instance_options.add_argument(
         "--trust-config",
         metavar="FILE",
-        type=str,
+        type=Path,
         help="The client trust configuration to use",
     )
     subcommands = parser.add_subparsers(
@@ -515,9 +515,9 @@ def _sign(args: argparse.Namespace) -> None:
     if args.staging:
         _logger.debug("sign: staging instances requested")
         signing_ctx = SigningContext.staging()
-        args.oidc_issuer = STAGING_OAUTH_ISSUER_URL
     elif args.trust_config:
-        raise ValueError("fuck")
+        trust_config = ClientTrustConfig.from_json(args.trust_config.read_text())
+        signing_ctx = SigningContext._from_trust_config(trust_config)
     else:
         # If the user didn't request the staging instance or pass in an
         # explicit client trust config, we're using the public good (i.e.
@@ -679,7 +679,8 @@ def _collect_verification_state(
         _logger.debug("verify: staging instances requested")
         verifier = Verifier.staging()
     elif args.trust_config:
-        raise ValueError("fuck")
+        trust_config = ClientTrustConfig.from_json(args.trust_config.read_text())
+        verifier = Verifier._from_trust_config(trust_config)
     else:
         verifier = Verifier.production()
 
diff --git a/sigstore/_internal/trust.py b/sigstore/_internal/trust.py
index 77801cf90..6b863c596 100644
--- a/sigstore/_internal/trust.py
+++ b/sigstore/_internal/trust.py
@@ -344,20 +344,22 @@ class ClientTrustConfig:
     """
 
     @classmethod
-    def from_json(cls, raw: str) -> None:
+    def from_json(cls, raw: str) -> ClientTrustConfig:
         """
         Deserialize the given client trust config.
         """
         inner = _ClientTrustConfig().from_json(raw)
-        cls(inner)
+        return cls(inner)
 
     def __init__(self, inner: _ClientTrustConfig) -> None:
         """
         @api private
         """
         self._inner = inner
-        # self._
 
-    # @property
-    # def trusted_root(self) -> TrustedRoot:
-    #     pass
+    @property
+    def trusted_root(self) -> TrustedRoot:
+        """
+        Return the interior root of trust, as a `TrustedRoot`.
+        """
+        return TrustedRoot(self._inner.trusted_root)
diff --git a/sigstore/sign.py b/sigstore/sign.py
index 1c59d345b..5392772c1 100644
--- a/sigstore/sign.py
+++ b/sigstore/sign.py
@@ -62,7 +62,7 @@
 )
 from sigstore._internal.rekor.client import RekorClient
 from sigstore._internal.sct import verify_sct
-from sigstore._internal.trust import KeyringPurpose, TrustedRoot
+from sigstore._internal.trust import ClientTrustConfig, KeyringPurpose, TrustedRoot
 from sigstore._utils import sha256_digest
 from sigstore.models import Bundle
 from sigstore.oidc import ExpiredIdentity, IdentityToken
@@ -333,6 +333,19 @@ def staging(cls) -> SigningContext:
             trusted_root=TrustedRoot.staging(),
         )
 
+    @classmethod
+    def _from_trust_config(cls, trust_config: ClientTrustConfig) -> SigningContext:
+        """
+        Create a `SigningContext` from the given `ClientTrustConfig`.
+
+        @api private
+        """
+        return cls(
+            fulcio=FulcioClient(trust_config._inner.signing_config.ca_url),
+            rekor=RekorClient(trust_config._inner.signing_config.tlog_urls[0]),
+            trusted_root=trust_config.trusted_root,
+        )
+
     @contextmanager
     def signer(
         self, identity_token: IdentityToken, *, cache: bool = True
diff --git a/sigstore/verify/verifier.py b/sigstore/verify/verifier.py
index 278a57a19..8f46df117 100644
--- a/sigstore/verify/verifier.py
+++ b/sigstore/verify/verifier.py
@@ -44,7 +44,7 @@
     _get_precertificate_signed_certificate_timestamps,
     verify_sct,
 )
-from sigstore._internal.trust import KeyringPurpose, TrustedRoot
+from sigstore._internal.trust import ClientTrustConfig, KeyringPurpose, TrustedRoot
 from sigstore._utils import base64_encode_pem_cert, sha256_digest
 from sigstore.errors import VerificationError
 from sigstore.hashes import Hashed
@@ -96,6 +96,18 @@ def staging(cls) -> Verifier:
             trusted_root=TrustedRoot.staging(),
         )
 
+    @classmethod
+    def _from_trust_config(cls, trust_config: ClientTrustConfig) -> Verifier:
+        """
+        Create a `Verifier` from the given `ClientTrustConfig`.
+
+        @api private
+        """
+        return cls(
+            rekor=RekorClient(trust_config._inner.signing_config.tlog_urls[0]),
+            trusted_root=trust_config.trusted_root,
+        )
+
     def _verify_common_signing_cert(
         self, bundle: Bundle, policy: VerificationPolicy
     ) -> None:

From 02d121bae79b2c20c78bd10bc8a02c1e24007b61 Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Tue, 14 May 2024 18:29:16 -0400
Subject: [PATCH 11/18] README: update `--help`

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 README.md | 70 +++++++++++++------------------------------------------
 1 file changed, 16 insertions(+), 54 deletions(-)

diff --git a/README.md b/README.md
index 8f115fda5..c86fa64e0 100644
--- a/README.md
+++ b/README.md
@@ -96,29 +96,26 @@ Top-level:
 
 <!-- @begin-sigstore-help@ -->
 ```
-usage: sigstore [-h] [-v] [-V] [--staging] [--rekor-url URL] COMMAND ...
+usage: sigstore [-h] [-v] [-V] [--staging | --trust-config FILE] COMMAND ...
 
 a tool for signing and verifying Python package distributions
 
 positional arguments:
-  COMMAND             the operation to perform
-    sign              sign one or more inputs
-    verify            verify one or more inputs
+  COMMAND              the operation to perform
+    sign               sign one or more inputs
+    verify             verify one or more inputs
     get-identity-token
-                      retrieve and return a Sigstore-compatible OpenID Connect
-                      token
+                       retrieve and return a Sigstore-compatible OpenID
+                       Connect token
 
 optional arguments:
-  -h, --help          show this help message and exit
-  -v, --verbose       run with additional debug logging; supply multiple times
-                      to increase verbosity (default: 0)
-  -V, --version       show program's version number and exit
-
-Sigstore instance options:
-  --staging           Use sigstore's staging instances, instead of the default
-                      production instances (default: False)
-  --rekor-url URL     The Rekor instance to use (conflicts with --staging)
-                      (default: https://rekor.sigstore.dev)
+  -h, --help           show this help message and exit
+  -v, --verbose        run with additional debug logging; supply multiple
+                       times to increase verbosity (default: 0)
+  -V, --version        show program's version number and exit
+  --staging            Use sigstore's staging instances, instead of the
+                       default production instances (default: False)
+  --trust-config FILE  The client trust configuration to use (default: None)
 ```
 <!-- @end-sigstore-help@ -->
 
@@ -132,8 +129,7 @@ usage: sigstore sign [-h] [-v] [--identity-token TOKEN] [--oidc-client-id ID]
                      [--oidc-disable-ambient-providers] [--oidc-issuer URL]
                      [--oauth-force-oob] [--no-default-files]
                      [--signature FILE] [--certificate FILE] [--bundle FILE]
-                     [--output-directory DIR] [--overwrite] [--staging]
-                     [--rekor-url URL] [--fulcio-url URL]
+                     [--output-directory DIR] [--overwrite]
                      FILE [FILE ...]
 
 positional arguments:
@@ -178,18 +174,6 @@ Output options:
                         (default: None)
   --overwrite           Overwrite preexisting signature and certificate
                         outputs, if present (default: False)
-
-Sigstore instance options:
-  --staging             Use sigstore's staging instances, instead of the
-                        default production instances. This option will be
-                        deprecated in favor of the global `--staging` option
-                        in a future release. (default: False)
-  --rekor-url URL       The Rekor instance to use (conflicts with --staging).
-                        This option will be deprecated in favor of the global
-                        `--rekor-url` option in a future release. (default:
-                        None)
-  --fulcio-url URL      The Fulcio instance to use (conflicts with --staging)
-                        (default: https://fulcio.sigstore.dev)
 ```
 <!-- @end-sigstore-sign-help@ -->
 
@@ -207,8 +191,7 @@ to by a particular OIDC provider (like `https://github.com/login/oauth`).
 usage: sigstore verify identity [-h] [-v] [--certificate FILE]
                                 [--signature FILE] [--bundle FILE]
                                 --cert-identity IDENTITY [--offline]
-                                --cert-oidc-issuer URL [--staging]
-                                [--rekor-url URL]
+                                --cert-oidc-issuer URL
                                 FILE [FILE ...]
 
 optional arguments:
@@ -235,16 +218,6 @@ Verification options:
   --cert-oidc-issuer URL
                         The OIDC issuer URL to check for in the certificate's
                         OIDC issuer extension (default: None)
-
-Sigstore instance options:
-  --staging             Use sigstore's staging instances, instead of the
-                        default production instances. This option will be
-                        deprecated in favor of the global `--staging` option
-                        in a future release. (default: False)
-  --rekor-url URL       The Rekor instance to use (conflicts with --staging).
-                        This option will be deprecated in favor of the global
-                        `--rekor-url` option in a future release. (default:
-                        None)
 ```
 <!-- @end-sigstore-verify-identity-help@ -->
 
@@ -261,8 +234,7 @@ usage: sigstore verify github [-h] [-v] [--certificate FILE]
                               [--signature FILE] [--bundle FILE]
                               --cert-identity IDENTITY [--offline]
                               [--trigger EVENT] [--sha SHA] [--name NAME]
-                              [--repository REPO] [--ref REF] [--staging]
-                              [--rekor-url URL]
+                              [--repository REPO] [--ref REF]
                               FILE [FILE ...]
 
 optional arguments:
@@ -296,16 +268,6 @@ Verification options:
                         under (default: None)
   --ref REF             The `git` ref that the workflow was invoked with
                         (default: None)
-
-Sigstore instance options:
-  --staging             Use sigstore's staging instances, instead of the
-                        default production instances. This option will be
-                        deprecated in favor of the global `--staging` option
-                        in a future release. (default: False)
-  --rekor-url URL       The Rekor instance to use (conflicts with --staging).
-                        This option will be deprecated in favor of the global
-                        `--rekor-url` option in a future release. (default:
-                        None)
 ```
 <!-- @end-sigstore-verify-github-help@ -->
 

From e283cf70c058de40bd2944b0377bd588967d70cb Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Wed, 15 May 2024 11:31:10 -0400
Subject: [PATCH 12/18] README: document BYO PKI

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 README.md | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/README.md b/README.md
index c86fa64e0..cecc7c163 100644
--- a/README.md
+++ b/README.md
@@ -24,6 +24,7 @@ else!
   * [Verifying](#verifying)
     * [Generic identities](#generic-identities)
     * [Signatures from GitHub Actions](#signatures-from-github-actions)
+  * [Advanced usage](#advanced-usage)
 * [Example uses](#example-uses)
   * [Signing with ambient credentials](#signing-with-ambient-credentials)
   * [Signing with an email identity](#signing-with-an-email-identity)
@@ -271,6 +272,29 @@ Verification options:
 ```
 <!-- @end-sigstore-verify-github-help@ -->
 
+## Advanced usage
+
+### Configuring a custom root of trust ("BYO PKI")
+
+Apart from the default and "staging" Sigstore instances, `sigstore` also
+supports "BYO PKI" setups, where a user maintains their own Sigstore
+instance services.
+
+These are supported via the `--trust-config` flag, which accepts a
+JSON-formatted file conforming to the `ClientTrustConfig` message
+in the [Sigstore protobuf specs](https://github.com/sigstore/protobuf-specs).
+This file configures the entire Sigstore instance state, *including* the URIs
+used to access the CA and artifact transparency services as well as the
+cryptographic root of trust itself.
+
+To use a custom client config, prepend `--trust-config` to any `sigstore`
+command:
+
+```console
+$ sigstore --trust-config custom.trustconfig.json sign foo.txt
+$ sigstore --trust-config custom.trustconfig.json verify identity foo.txt ...
+```
+
 ## Example uses
 
 `sigstore` supports a wide variety of workflows and usages. Some common ones are

From 670a3cfc35d1b6ad9ada0920c1826df47bb612c2 Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Wed, 15 May 2024 11:40:37 -0400
Subject: [PATCH 13/18] sigstore: enforce client trust config media type

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 sigstore/_internal/trust.py | 28 +++++++++++++++++++++++++++-
 sigstore/models.py          |  4 ++--
 2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/sigstore/_internal/trust.py b/sigstore/_internal/trust.py
index 6b863c596..aac5addab 100644
--- a/sigstore/_internal/trust.py
+++ b/sigstore/_internal/trust.py
@@ -55,7 +55,7 @@
     key_id,
     load_der_public_key,
 )
-from sigstore.errors import MetadataError, VerificationError
+from sigstore.errors import Error, MetadataError, VerificationError
 
 
 def _is_timerange_valid(period: TimeRange | None, *, allow_expired: bool) -> bool:
@@ -343,6 +343,17 @@ class ClientTrustConfig:
     Represents a Sigstore client's trust configuration, including a root of trust.
     """
 
+    class ClientTrustConfigType(str, Enum):
+        """
+        Known Sigstore client trust config media types.
+        """
+
+        CONFIG_0_1 = "application/vnd.dev.sigstore.clienttrustconfig.v0.1+json"
+
+        def __str__(self) -> str:
+            """Returns the variant's string value."""
+            return self.value
+
     @classmethod
     def from_json(cls, raw: str) -> ClientTrustConfig:
         """
@@ -356,6 +367,21 @@ def __init__(self, inner: _ClientTrustConfig) -> None:
         @api private
         """
         self._inner = inner
+        self._verify()
+
+    def _verify(self) -> None:
+        """
+        Performs various feats of heroism to ensure that the client trust config
+        is well-formed.
+        """
+
+        # The client trust config must have a recognized media type.
+        try:
+            ClientTrustConfig(self._inner.media_type)
+        except ValueError:
+            raise Error(
+                f"unsupported client trust config format: {self._inner.media_type}"
+            )
 
     @property
     def trusted_root(self) -> TrustedRoot:
diff --git a/sigstore/models.py b/sigstore/models.py
index 375ff6458..dea5c7314 100644
--- a/sigstore/models.py
+++ b/sigstore/models.py
@@ -358,9 +358,9 @@ def __init__(self, inner: _Bundle) -> None:
         @private
         """
         self._inner = inner
-        self._verify_bundle()
+        self._verify()
 
-    def _verify_bundle(self) -> None:
+    def _verify(self) -> None:
         """
         Performs various feats of heroism to ensure the bundle is well-formed
         and upholds invariants, including:

From 4bb731c912a744fcabeca5289d46cf73ce97c5d2 Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Wed, 15 May 2024 11:41:22 -0400
Subject: [PATCH 14/18] fix type

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 sigstore/_internal/trust.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sigstore/_internal/trust.py b/sigstore/_internal/trust.py
index aac5addab..ed8c88b35 100644
--- a/sigstore/_internal/trust.py
+++ b/sigstore/_internal/trust.py
@@ -377,7 +377,7 @@ def _verify(self) -> None:
 
         # The client trust config must have a recognized media type.
         try:
-            ClientTrustConfig(self._inner.media_type)
+            ClientTrustConfig.ClientTrustConfigType(self._inner.media_type)
         except ValueError:
             raise Error(
                 f"unsupported client trust config format: {self._inner.media_type}"

From 8f6e42f179b7e3da49d9060478be83e73c1c0519 Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Wed, 15 May 2024 11:54:57 -0400
Subject: [PATCH 15/18] enforce media types, unit tests

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 sigstore/_internal/trust.py                   |  24 ++++
 .../assets/trust_config/config.badtype.json   | 127 ++++++++++++++++++
 test/unit/assets/trust_config/config.v1.json  | 127 ++++++++++++++++++
 test/unit/internal/test_trust.py              |  23 +++-
 4 files changed, 300 insertions(+), 1 deletion(-)
 create mode 100644 test/unit/assets/trust_config/config.badtype.json
 create mode 100644 test/unit/assets/trust_config/config.v1.json

diff --git a/sigstore/_internal/trust.py b/sigstore/_internal/trust.py
index ed8c88b35..d660bee56 100644
--- a/sigstore/_internal/trust.py
+++ b/sigstore/_internal/trust.py
@@ -222,6 +222,17 @@ class TrustedRoot:
     The cryptographic root(s) of trust for a Sigstore instance.
     """
 
+    class TrustedRootType(str, Enum):
+        """
+        Known Sigstore trusted root media types.
+        """
+
+        TRUSTED_ROOT_0_1 = "application/vnd.dev.sigstore.trustedroot+json;version=0.1"
+
+        def __str__(self) -> str:
+            """Returns the variant's string value."""
+            return self.value
+
     def __init__(self, inner: _TrustedRoot):
         """
         Construct a new `TrustedRoot`.
@@ -229,6 +240,19 @@ def __init__(self, inner: _TrustedRoot):
         @api private
         """
         self._inner = inner
+        self._verify()
+
+    def _verify(self) -> None:
+        """
+        Performs various feats of heroism to ensure that the trusted root
+        is well-formed.
+        """
+
+        # The trusted root must have a recognized media type.
+        try:
+            TrustedRoot.TrustedRootType(self._inner.media_type)
+        except ValueError:
+            raise Error(f"unsupported trusted root format: {self._inner.media_type}")
 
     @classmethod
     def from_file(
diff --git a/test/unit/assets/trust_config/config.badtype.json b/test/unit/assets/trust_config/config.badtype.json
new file mode 100644
index 000000000..3f0ef4812
--- /dev/null
+++ b/test/unit/assets/trust_config/config.badtype.json
@@ -0,0 +1,127 @@
+{
+    "mediaType": "bad-media-type",
+    "trustedRoot": {
+        "mediaType": "application/vnd.dev.sigstore.trustedroot+json;version=0.1",
+        "tlogs": [
+            {
+                "baseUrl": "https://rekor.sigstore.dev",
+                "hashAlgorithm": "SHA2_256",
+                "publicKey": {
+                    "rawBytes": "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE2G2Y+2tabdTV5BcGiBIx0a9fAFwrkBbmLSGtks4L3qX6yYY0zufBnhC8Ur/iy55GhWP/9A/bY2LhC30M9+RYtw==",
+                    "keyDetails": "PKIX_ECDSA_P256_SHA_256",
+                    "validFor": {
+                        "start": "2021-01-12T11:53:27.000Z"
+                    }
+                },
+                "logId": {
+                    "keyId": "wNI9atQGlz+VWfO6LRygH4QUfY/8W4RFwiT5i5WRgB0="
+                }
+            }
+        ],
+        "certificateAuthorities": [
+            {
+                "subject": {
+                    "organization": "sigstore.dev",
+                    "commonName": "sigstore"
+                },
+                "uri": "https://fulcio.sigstore.dev",
+                "certChain": {
+                    "certificates": [
+                        {
+                            "rawBytes": "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"
+                        }
+                    ]
+                },
+                "validFor": {
+                    "start": "2021-03-07T03:20:29.000Z",
+                    "end": "2022-12-31T23:59:59.999Z"
+                }
+            },
+            {
+                "subject": {
+                    "organization": "sigstore.dev",
+                    "commonName": "sigstore"
+                },
+                "uri": "https://fulcio.sigstore.dev",
+                "certChain": {
+                    "certificates": [
+                        {
+                            "rawBytes": "MIICGjCCAaGgAwIBAgIUALnViVfnU0brJasmRkHrn/UnfaQwCgYIKoZIzj0EAwMwKjEVMBMGA1UEChMMc2lnc3RvcmUuZGV2MREwDwYDVQQDEwhzaWdzdG9yZTAeFw0yMjA0MTMyMDA2MTVaFw0zMTEwMDUxMzU2NThaMDcxFTATBgNVBAoTDHNpZ3N0b3JlLmRldjEeMBwGA1UEAxMVc2lnc3RvcmUtaW50ZXJtZWRpYXRlMHYwEAYHKoZIzj0CAQYFK4EEACIDYgAE8RVS/ysH+NOvuDZyPIZtilgUF9NlarYpAd9HP1vBBH1U5CV77LSS7s0ZiH4nE7Hv7ptS6LvvR/STk798LVgMzLlJ4HeIfF3tHSaexLcYpSASr1kS0N/RgBJz/9jWCiXno3sweTAOBgNVHQ8BAf8EBAMCAQYwEwYDVR0lBAwwCgYIKwYBBQUHAwMwEgYDVR0TAQH/BAgwBgEB/wIBADAdBgNVHQ4EFgQU39Ppz1YkEZb5qNjpKFWixi4YZD8wHwYDVR0jBBgwFoAUWMAeX5FFpWapesyQoZMi0CrFxfowCgYIKoZIzj0EAwMDZwAwZAIwPCsQK4DYiZYDPIaDi5HFKnfxXx6ASSVmERfsynYBiX2X6SJRnZU84/9DZdnFvvxmAjBOt6QpBlc4J/0DxvkTCqpclvziL6BCCPnjdlIB3Pu3BxsPmygUY7Ii2zbdCdliiow="
+                        },
+                        {
+                            "rawBytes": "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"
+                        }
+                    ]
+                },
+                "validFor": {
+                    "start": "2022-04-13T20:06:15.000Z"
+                }
+            }
+        ],
+        "ctlogs": [
+            {
+                "baseUrl": "https://ctfe.sigstore.dev/test",
+                "hashAlgorithm": "SHA2_256",
+                "publicKey": {
+                    "rawBytes": "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEbfwR+RJudXscgRBRpKX1XFDy3PyudDxz/SfnRi1fT8ekpfBd2O1uoz7jr3Z8nKzxA69EUQ+eFCFI3zeubPWU7w==",
+                    "keyDetails": "PKIX_ECDSA_P256_SHA_256",
+                    "validFor": {
+                        "start": "2021-03-14T00:00:00.000Z",
+                        "end": "2022-10-31T23:59:59.999Z"
+                    }
+                },
+                "logId": {
+                    "keyId": "CGCS8ChS/2hF0dFrJ4ScRWcYrBY9wzjSbea8IgY2b3I="
+                }
+            },
+            {
+                "baseUrl": "https://ctfe.sigstore.dev/2022",
+                "hashAlgorithm": "SHA2_256",
+                "publicKey": {
+                    "rawBytes": "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEiPSlFi0CmFTfEjCUqF9HuCEcYXNKAaYalIJmBZ8yyezPjTqhxrKBpMnaocVtLJBI1eM3uXnQzQGAJdJ4gs9Fyw==",
+                    "keyDetails": "PKIX_ECDSA_P256_SHA_256",
+                    "validFor": {
+                        "start": "2022-10-20T00:00:00.000Z"
+                    }
+                },
+                "logId": {
+                    "keyId": "3T0wasbHETJjGR4cmWc3AqJKXrjePK3/h4pygC8p7o4="
+                }
+            }
+        ],
+        "timestampAuthorities": [
+            {
+                "subject": {
+                    "organization": "GitHub, Inc.",
+                    "commonName": "Internal Services Root"
+                },
+                "certChain": {
+                    "certificates": [
+                        {
+                            "rawBytes": "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"
+                        },
+                        {
+                            "rawBytes": "MIICEDCCAZWgAwIBAgIUX8ZO5QXP7vN4dMQ5e9sU3nub8OgwCgYIKoZIzj0EAwMwODEVMBMGA1UEChMMR2l0SHViLCBJbmMuMR8wHQYDVQQDExZJbnRlcm5hbCBTZXJ2aWNlcyBSb290MB4XDTIzMDQxNDAwMDAwMFoXDTI4MDQxMjAwMDAwMFowMjEVMBMGA1UEChMMR2l0SHViLCBJbmMuMRkwFwYDVQQDExBUU0EgaW50ZXJtZWRpYXRlMHYwEAYHKoZIzj0CAQYFK4EEACIDYgAEvMLY/dTVbvIJYANAuszEwJnQE1llftynyMKIMhh48HmqbVr5ygybzsLRLVKbBWOdZ21aeJz+gZiytZetqcyF9WlER5NEMf6JV7ZNojQpxHq4RHGoGSceQv/qvTiZxEDKo2YwZDAOBgNVHQ8BAf8EBAMCAQYwEgYDVR0TAQH/BAgwBgEB/wIBADAdBgNVHQ4EFgQUaW1RudOgVt0leqY0WKYbuPr47wAwHwYDVR0jBBgwFoAU9NYYlobnAG4c0/qjxyH/lq/wz+QwCgYIKoZIzj0EAwMDaQAwZgIxAK1B185ygCrIYFlIs3GjswjnwSMG6LY8woLVdakKDZxVa8f8cqMs1DhcxJ0+09w95QIxAO+tBzZk7vjUJ9iJgD4R6ZWTxQWKqNm74jO99o+o9sv4FI/SZTZTFyMn0IJEHdNmyA=="
+                        },
+                        {
+                            "rawBytes": "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"
+                        }
+                    ]
+                },
+                "validFor": {
+                    "start": "2023-04-14T00:00:00.000Z"
+                }
+            }
+        ]
+    },
+    "signingConfig": {
+        "caUrl": "https://fakeca.example.com",
+        "oidcUrl": "https://fakeoidc.example.com",
+        "tlogUrls": [
+            "https://fakelog.example.com"
+        ],
+        "tsaUrls": [
+            "https://faketsa.example.com"
+        ]
+    }
+}
diff --git a/test/unit/assets/trust_config/config.v1.json b/test/unit/assets/trust_config/config.v1.json
new file mode 100644
index 000000000..d3fae7ac6
--- /dev/null
+++ b/test/unit/assets/trust_config/config.v1.json
@@ -0,0 +1,127 @@
+{
+    "mediaType": "application/vnd.dev.sigstore.clienttrustconfig.v0.1+json",
+    "trustedRoot": {
+        "mediaType": "application/vnd.dev.sigstore.trustedroot+json;version=0.1",
+        "tlogs": [
+            {
+                "baseUrl": "https://rekor.sigstore.dev",
+                "hashAlgorithm": "SHA2_256",
+                "publicKey": {
+                    "rawBytes": "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE2G2Y+2tabdTV5BcGiBIx0a9fAFwrkBbmLSGtks4L3qX6yYY0zufBnhC8Ur/iy55GhWP/9A/bY2LhC30M9+RYtw==",
+                    "keyDetails": "PKIX_ECDSA_P256_SHA_256",
+                    "validFor": {
+                        "start": "2021-01-12T11:53:27.000Z"
+                    }
+                },
+                "logId": {
+                    "keyId": "wNI9atQGlz+VWfO6LRygH4QUfY/8W4RFwiT5i5WRgB0="
+                }
+            }
+        ],
+        "certificateAuthorities": [
+            {
+                "subject": {
+                    "organization": "sigstore.dev",
+                    "commonName": "sigstore"
+                },
+                "uri": "https://fulcio.sigstore.dev",
+                "certChain": {
+                    "certificates": [
+                        {
+                            "rawBytes": "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"
+                        }
+                    ]
+                },
+                "validFor": {
+                    "start": "2021-03-07T03:20:29.000Z",
+                    "end": "2022-12-31T23:59:59.999Z"
+                }
+            },
+            {
+                "subject": {
+                    "organization": "sigstore.dev",
+                    "commonName": "sigstore"
+                },
+                "uri": "https://fulcio.sigstore.dev",
+                "certChain": {
+                    "certificates": [
+                        {
+                            "rawBytes": "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"
+                        },
+                        {
+                            "rawBytes": "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"
+                        }
+                    ]
+                },
+                "validFor": {
+                    "start": "2022-04-13T20:06:15.000Z"
+                }
+            }
+        ],
+        "ctlogs": [
+            {
+                "baseUrl": "https://ctfe.sigstore.dev/test",
+                "hashAlgorithm": "SHA2_256",
+                "publicKey": {
+                    "rawBytes": "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEbfwR+RJudXscgRBRpKX1XFDy3PyudDxz/SfnRi1fT8ekpfBd2O1uoz7jr3Z8nKzxA69EUQ+eFCFI3zeubPWU7w==",
+                    "keyDetails": "PKIX_ECDSA_P256_SHA_256",
+                    "validFor": {
+                        "start": "2021-03-14T00:00:00.000Z",
+                        "end": "2022-10-31T23:59:59.999Z"
+                    }
+                },
+                "logId": {
+                    "keyId": "CGCS8ChS/2hF0dFrJ4ScRWcYrBY9wzjSbea8IgY2b3I="
+                }
+            },
+            {
+                "baseUrl": "https://ctfe.sigstore.dev/2022",
+                "hashAlgorithm": "SHA2_256",
+                "publicKey": {
+                    "rawBytes": "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEiPSlFi0CmFTfEjCUqF9HuCEcYXNKAaYalIJmBZ8yyezPjTqhxrKBpMnaocVtLJBI1eM3uXnQzQGAJdJ4gs9Fyw==",
+                    "keyDetails": "PKIX_ECDSA_P256_SHA_256",
+                    "validFor": {
+                        "start": "2022-10-20T00:00:00.000Z"
+                    }
+                },
+                "logId": {
+                    "keyId": "3T0wasbHETJjGR4cmWc3AqJKXrjePK3/h4pygC8p7o4="
+                }
+            }
+        ],
+        "timestampAuthorities": [
+            {
+                "subject": {
+                    "organization": "GitHub, Inc.",
+                    "commonName": "Internal Services Root"
+                },
+                "certChain": {
+                    "certificates": [
+                        {
+                            "rawBytes": "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"
+                        },
+                        {
+                            "rawBytes": "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"
+                        },
+                        {
+                            "rawBytes": "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"
+                        }
+                    ]
+                },
+                "validFor": {
+                    "start": "2023-04-14T00:00:00.000Z"
+                }
+            }
+        ]
+    },
+    "signingConfig": {
+        "caUrl": "https://fakeca.example.com",
+        "oidcUrl": "https://fakeoidc.example.com",
+        "tlogUrls": [
+            "https://fakelog.example.com"
+        ],
+        "tsaUrls": [
+            "https://faketsa.example.com"
+        ]
+    }
+}
diff --git a/test/unit/internal/test_trust.py b/test/unit/internal/test_trust.py
index cc55c8fcf..60de5de48 100644
--- a/test/unit/internal/test_trust.py
+++ b/test/unit/internal/test_trust.py
@@ -22,12 +22,13 @@
 from sigstore_protobuf_specs.dev.sigstore.common.v1 import TimeRange
 
 from sigstore._internal.trust import (
+    ClientTrustConfig,
     KeyringPurpose,
     TrustedRoot,
     _is_timerange_valid,
 )
 from sigstore._utils import load_pem_public_key
-from sigstore.errors import RootError
+from sigstore.errors import Error, RootError
 
 
 def test_trust_root_tuf_caches_and_requests(mock_staging_tuf, tuf_dirs):
@@ -242,3 +243,23 @@ def test_trust_root_fulcio_certs_error(tuf_asset, monkeypatch):
         Exception, match="Fulcio certificates not found in trusted root"
     ):
         trust_root.get_fulcio_certs()
+
+
+class TestClientTrustConfig:
+    def test_good(self, asset):
+        path = asset("trust_config/config.v1.json")
+        config = ClientTrustConfig.from_json(path.read_text())
+
+        assert config._inner.signing_config.ca_url == "https://fakeca.example.com"
+        assert config._inner.signing_config.oidc_url == "https://fakeoidc.example.com"
+        assert config._inner.signing_config.tlog_urls == ["https://fakelog.example.com"]
+        assert config._inner.signing_config.tsa_urls == ["https://faketsa.example.com"]
+        assert isinstance(config.trusted_root, TrustedRoot)
+
+    def test_bad_media_type(self, asset):
+        path = asset("trust_config/config.badtype.json")
+
+        with pytest.raises(
+            Error, match="unsupported client trust config format: bad-media-type"
+        ):
+            ClientTrustConfig.from_json(path.read_text())

From 979ac6d9bc6409962c791dce1247275ebb272a51 Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Wed, 15 May 2024 12:02:41 -0400
Subject: [PATCH 16/18] test: more trust tests

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 .../trusted_root/trustedroot.badtype.json     | 114 ++++++++++++++++++
 .../assets/trusted_root/trustedroot.v1.json   | 114 ++++++++++++++++++
 test/unit/internal/test_trust.py              |  25 ++++
 3 files changed, 253 insertions(+)
 create mode 100644 test/unit/assets/trusted_root/trustedroot.badtype.json
 create mode 100644 test/unit/assets/trusted_root/trustedroot.v1.json

diff --git a/test/unit/assets/trusted_root/trustedroot.badtype.json b/test/unit/assets/trusted_root/trustedroot.badtype.json
new file mode 100644
index 000000000..539ce3227
--- /dev/null
+++ b/test/unit/assets/trusted_root/trustedroot.badtype.json
@@ -0,0 +1,114 @@
+{
+    "mediaType": "bad-media-type",
+    "tlogs": [
+        {
+            "baseUrl": "https://rekor.sigstore.dev",
+            "hashAlgorithm": "SHA2_256",
+            "publicKey": {
+                "rawBytes": "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE2G2Y+2tabdTV5BcGiBIx0a9fAFwrkBbmLSGtks4L3qX6yYY0zufBnhC8Ur/iy55GhWP/9A/bY2LhC30M9+RYtw==",
+                "keyDetails": "PKIX_ECDSA_P256_SHA_256",
+                "validFor": {
+                    "start": "2021-01-12T11:53:27.000Z"
+                }
+            },
+            "logId": {
+                "keyId": "wNI9atQGlz+VWfO6LRygH4QUfY/8W4RFwiT5i5WRgB0="
+            }
+        }
+    ],
+    "certificateAuthorities": [
+        {
+            "subject": {
+                "organization": "sigstore.dev",
+                "commonName": "sigstore"
+            },
+            "uri": "https://fulcio.sigstore.dev",
+            "certChain": {
+                "certificates": [
+                    {
+                        "rawBytes": "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"
+                    }
+                ]
+            },
+            "validFor": {
+                "start": "2021-03-07T03:20:29.000Z",
+                "end": "2022-12-31T23:59:59.999Z"
+            }
+        },
+        {
+            "subject": {
+                "organization": "sigstore.dev",
+                "commonName": "sigstore"
+            },
+            "uri": "https://fulcio.sigstore.dev",
+            "certChain": {
+                "certificates": [
+                    {
+                        "rawBytes": "MIICGjCCAaGgAwIBAgIUALnViVfnU0brJasmRkHrn/UnfaQwCgYIKoZIzj0EAwMwKjEVMBMGA1UEChMMc2lnc3RvcmUuZGV2MREwDwYDVQQDEwhzaWdzdG9yZTAeFw0yMjA0MTMyMDA2MTVaFw0zMTEwMDUxMzU2NThaMDcxFTATBgNVBAoTDHNpZ3N0b3JlLmRldjEeMBwGA1UEAxMVc2lnc3RvcmUtaW50ZXJtZWRpYXRlMHYwEAYHKoZIzj0CAQYFK4EEACIDYgAE8RVS/ysH+NOvuDZyPIZtilgUF9NlarYpAd9HP1vBBH1U5CV77LSS7s0ZiH4nE7Hv7ptS6LvvR/STk798LVgMzLlJ4HeIfF3tHSaexLcYpSASr1kS0N/RgBJz/9jWCiXno3sweTAOBgNVHQ8BAf8EBAMCAQYwEwYDVR0lBAwwCgYIKwYBBQUHAwMwEgYDVR0TAQH/BAgwBgEB/wIBADAdBgNVHQ4EFgQU39Ppz1YkEZb5qNjpKFWixi4YZD8wHwYDVR0jBBgwFoAUWMAeX5FFpWapesyQoZMi0CrFxfowCgYIKoZIzj0EAwMDZwAwZAIwPCsQK4DYiZYDPIaDi5HFKnfxXx6ASSVmERfsynYBiX2X6SJRnZU84/9DZdnFvvxmAjBOt6QpBlc4J/0DxvkTCqpclvziL6BCCPnjdlIB3Pu3BxsPmygUY7Ii2zbdCdliiow="
+                    },
+                    {
+                        "rawBytes": "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"
+                    }
+                ]
+            },
+            "validFor": {
+                "start": "2022-04-13T20:06:15.000Z"
+            }
+        }
+    ],
+    "ctlogs": [
+        {
+            "baseUrl": "https://ctfe.sigstore.dev/test",
+            "hashAlgorithm": "SHA2_256",
+            "publicKey": {
+                "rawBytes": "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEbfwR+RJudXscgRBRpKX1XFDy3PyudDxz/SfnRi1fT8ekpfBd2O1uoz7jr3Z8nKzxA69EUQ+eFCFI3zeubPWU7w==",
+                "keyDetails": "PKIX_ECDSA_P256_SHA_256",
+                "validFor": {
+                    "start": "2021-03-14T00:00:00.000Z",
+                    "end": "2022-10-31T23:59:59.999Z"
+                }
+            },
+            "logId": {
+                "keyId": "CGCS8ChS/2hF0dFrJ4ScRWcYrBY9wzjSbea8IgY2b3I="
+            }
+        },
+        {
+            "baseUrl": "https://ctfe.sigstore.dev/2022",
+            "hashAlgorithm": "SHA2_256",
+            "publicKey": {
+                "rawBytes": "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEiPSlFi0CmFTfEjCUqF9HuCEcYXNKAaYalIJmBZ8yyezPjTqhxrKBpMnaocVtLJBI1eM3uXnQzQGAJdJ4gs9Fyw==",
+                "keyDetails": "PKIX_ECDSA_P256_SHA_256",
+                "validFor": {
+                    "start": "2022-10-20T00:00:00.000Z"
+                }
+            },
+            "logId": {
+                "keyId": "3T0wasbHETJjGR4cmWc3AqJKXrjePK3/h4pygC8p7o4="
+            }
+        }
+    ],
+    "timestampAuthorities": [
+        {
+            "subject": {
+                "organization": "GitHub, Inc.",
+                "commonName": "Internal Services Root"
+            },
+            "certChain": {
+                "certificates": [
+                    {
+                        "rawBytes": "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"
+                    },
+                    {
+                        "rawBytes": "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"
+                    },
+                    {
+                        "rawBytes": "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"
+                    }
+                ]
+            },
+            "validFor": {
+                "start": "2023-04-14T00:00:00.000Z"
+            }
+        }
+    ]
+}
diff --git a/test/unit/assets/trusted_root/trustedroot.v1.json b/test/unit/assets/trusted_root/trustedroot.v1.json
new file mode 100644
index 000000000..190c76a65
--- /dev/null
+++ b/test/unit/assets/trusted_root/trustedroot.v1.json
@@ -0,0 +1,114 @@
+{
+    "mediaType": "application/vnd.dev.sigstore.trustedroot+json;version=0.1",
+    "tlogs": [
+        {
+            "baseUrl": "https://rekor.sigstore.dev",
+            "hashAlgorithm": "SHA2_256",
+            "publicKey": {
+                "rawBytes": "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE2G2Y+2tabdTV5BcGiBIx0a9fAFwrkBbmLSGtks4L3qX6yYY0zufBnhC8Ur/iy55GhWP/9A/bY2LhC30M9+RYtw==",
+                "keyDetails": "PKIX_ECDSA_P256_SHA_256",
+                "validFor": {
+                    "start": "2021-01-12T11:53:27.000Z"
+                }
+            },
+            "logId": {
+                "keyId": "wNI9atQGlz+VWfO6LRygH4QUfY/8W4RFwiT5i5WRgB0="
+            }
+        }
+    ],
+    "certificateAuthorities": [
+        {
+            "subject": {
+                "organization": "sigstore.dev",
+                "commonName": "sigstore"
+            },
+            "uri": "https://fulcio.sigstore.dev",
+            "certChain": {
+                "certificates": [
+                    {
+                        "rawBytes": "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"
+                    }
+                ]
+            },
+            "validFor": {
+                "start": "2021-03-07T03:20:29.000Z",
+                "end": "2022-12-31T23:59:59.999Z"
+            }
+        },
+        {
+            "subject": {
+                "organization": "sigstore.dev",
+                "commonName": "sigstore"
+            },
+            "uri": "https://fulcio.sigstore.dev",
+            "certChain": {
+                "certificates": [
+                    {
+                        "rawBytes": "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"
+                    },
+                    {
+                        "rawBytes": "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"
+                    }
+                ]
+            },
+            "validFor": {
+                "start": "2022-04-13T20:06:15.000Z"
+            }
+        }
+    ],
+    "ctlogs": [
+        {
+            "baseUrl": "https://ctfe.sigstore.dev/test",
+            "hashAlgorithm": "SHA2_256",
+            "publicKey": {
+                "rawBytes": "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEbfwR+RJudXscgRBRpKX1XFDy3PyudDxz/SfnRi1fT8ekpfBd2O1uoz7jr3Z8nKzxA69EUQ+eFCFI3zeubPWU7w==",
+                "keyDetails": "PKIX_ECDSA_P256_SHA_256",
+                "validFor": {
+                    "start": "2021-03-14T00:00:00.000Z",
+                    "end": "2022-10-31T23:59:59.999Z"
+                }
+            },
+            "logId": {
+                "keyId": "CGCS8ChS/2hF0dFrJ4ScRWcYrBY9wzjSbea8IgY2b3I="
+            }
+        },
+        {
+            "baseUrl": "https://ctfe.sigstore.dev/2022",
+            "hashAlgorithm": "SHA2_256",
+            "publicKey": {
+                "rawBytes": "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEiPSlFi0CmFTfEjCUqF9HuCEcYXNKAaYalIJmBZ8yyezPjTqhxrKBpMnaocVtLJBI1eM3uXnQzQGAJdJ4gs9Fyw==",
+                "keyDetails": "PKIX_ECDSA_P256_SHA_256",
+                "validFor": {
+                    "start": "2022-10-20T00:00:00.000Z"
+                }
+            },
+            "logId": {
+                "keyId": "3T0wasbHETJjGR4cmWc3AqJKXrjePK3/h4pygC8p7o4="
+            }
+        }
+    ],
+    "timestampAuthorities": [
+        {
+            "subject": {
+                "organization": "GitHub, Inc.",
+                "commonName": "Internal Services Root"
+            },
+            "certChain": {
+                "certificates": [
+                    {
+                        "rawBytes": "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"
+                    },
+                    {
+                        "rawBytes": "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"
+                    },
+                    {
+                        "rawBytes": "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"
+                    }
+                ]
+            },
+            "validFor": {
+                "start": "2023-04-14T00:00:00.000Z"
+            }
+        }
+    ]
+}
diff --git a/test/unit/internal/test_trust.py b/test/unit/internal/test_trust.py
index 60de5de48..d74052e52 100644
--- a/test/unit/internal/test_trust.py
+++ b/test/unit/internal/test_trust.py
@@ -31,6 +31,31 @@
 from sigstore.errors import Error, RootError
 
 
+class TestTrustedRoot:
+    def test_good(self, asset):
+        path = asset("trusted_root/trustedroot.v1.json")
+        root = TrustedRoot.from_file(path)
+
+        assert (
+            root._inner.media_type == TrustedRoot.TrustedRootType.TRUSTED_ROOT_0_1.value
+        )
+        assert len(root._inner.tlogs) == 1
+        assert len(root._inner.certificate_authorities) == 2
+        assert len(root._inner.ctlogs) == 2
+        assert len(root._inner.timestamp_authorities) == 1
+
+    def test_bad_media_type(self, asset):
+        path = asset("trusted_root/trustedroot.badtype.json")
+
+        with pytest.raises(
+            Error, match="unsupported trusted root format: bad-media-type"
+        ):
+            TrustedRoot.from_file(path)
+
+
+# TODO(ww): Move these into appropriate class-scoped tests.
+
+
 def test_trust_root_tuf_caches_and_requests(mock_staging_tuf, tuf_dirs):
     # start with empty target cache, empty local metadata dir
     data_dir, cache_dir = tuf_dirs

From f7f33076ddda487c920743e3f3f0b970df2b17fb Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Wed, 15 May 2024 12:09:24 -0400
Subject: [PATCH 17/18] CHANGELOG: record changes

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 CHANGELOG.md | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e2c610803..8280ef06f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -28,6 +28,10 @@ All versions prior to 0.9.0 are untracked.
   for representing in-toto statements and DSSE envelopes
   ([#930](https://github.com/sigstore/sigstore-python/pull/930))
 
+* CLI: The `--trust-config` flag has been added as a global option,
+  enabling consistent "BYO PKI" uses of `sigstore` with a single flag
+  ([#1010](https://github.com/sigstore/sigstore-python/pull/1010))
+
 ### Removed
 
 * **BREAKING API CHANGE**: `SigningResult` has been removed.
@@ -44,6 +48,11 @@ All versions prior to 0.9.0 are untracked.
   The public verification and policy APIs now raise
   `sigstore.errors.VerificationError` on failure.
 
+* **BREAKING CLI CHANGE**: The `--rekor-url` and `--fulcio-url`
+  flags have been entirely removed. To configure a custom PKI, use
+  `--trust-config`
+  ([#1010](https://github.com/sigstore/sigstore-python/pull/1010))
+
 ### Changed
 
 * **BREAKING API CHANGE**: `Verifier.verify(...)`  now takes a `bytes | Hashed`

From 5c49a6dd829144e402a39dde72dcefaa8f318dae Mon Sep 17 00:00:00 2001
From: William Woodruff <william@trailofbits.com>
Date: Thu, 16 May 2024 10:39:25 -0400
Subject: [PATCH 18/18] README: fix `--help`

Signed-off-by: William Woodruff <william@trailofbits.com>
---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 8a61276b9..a2c6a30ed 100644
--- a/README.md
+++ b/README.md
@@ -238,7 +238,7 @@ usage: sigstore verify github [-h] [-v] [--certificate FILE]
                               [--ref REF]
                               FILE [FILE ...]
 
-options:
+optional arguments:
   -h, --help            show this help message and exit
   -v, --verbose         run with additional debug logging; supply multiple
                         times to increase verbosity (default: 0)