Add signing and verification methods based on in-toto statements (sig…

…store#193)

* signing and verification

Signed-off-by: Martin Sablotny <msablotny@nvidia.com>

* changed behavior to raise an exception on failure
license
gitignore newline
add dependencies

Signed-off-by: Martin Sablotny <msablotny@nvidia.com>

deps

* gitignore;requirements

Signed-off-by: Martin Sablotny <msablotny@nvidia.com>

* dependencies

Signed-off-by: Martin Sablotny <msablotny@nvidia.com>

* Bump frozen dependencies

Signed-off-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

* import paths

Signed-off-by: Martin Sablotny <msablotny@nvidia.com>

---------

Signed-off-by: Martin Sablotny <msablotny@nvidia.com>
Signed-off-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Signed-off-by: Martin Sablotny <susperius@gmail.com>
Co-authored-by: susperius <1203928+susperius@users.noreply.github.com>

.gitignore

@@ -1 +1,4 @@
 __pycache__/
+.venv/
+.pytest_cache/
+test_material/

model_signing/install/requirements.in

@@ -1,2 +1,9 @@
+absl-py
+betterproto
+cryptography
+in-toto-attestation
+pyOpenSSL
+protobuf
 psutil
 sigstore
+sigstore-protobuf-specs

model_signing/install/requirements_Darwin.txt

@@ -4,14 +4,20 @@
 #
 #    pip-compile --generate-hashes --output-file=model_signing/install/requirements_Darwin.txt --strip-extras model_signing/install/requirements.in
 #
+absl-py==2.1.0 \
+    --hash=sha256:526a04eadab8b4ee719ce68f204172ead1027549089702d99b9059f129ff1308 \
+    --hash=sha256:7820790efbb316739cde8b4e19357243fc3608a152024288513dd968d7d959ff
+    # via -r model_signing/install/requirements.in
 annotated-types==0.7.0 \
     --hash=sha256:1f02e8b43a8fbbc3f3e0d4f0f4bfc8131bcb4eebe8849b8e5c773f3a1c582a53 \
     --hash=sha256:aff07c09a53a08bc8cfccb9c85b05f1aa9a2a6f23728d790723543408344ce89
     # via pydantic
 betterproto==2.0.0b6 \
     --hash=sha256:720ae92697000f6fcf049c69267d957f0871654c8b0d7458906607685daee784 \
     --hash=sha256:a0839ec165d110a69d0d116f4d0e2bec8d186af4db826257931f0831dab73fcf
-    # via sigstore-protobuf-specs
+    # via
+    #   -r model_signing/install/requirements.in
+    #   sigstore-protobuf-specs
 certifi==2024.7.4 \
     --hash=sha256:5a1e7645bc0ec61a09e26c36f6106dd4cf40c6db3a1fb6352b0244e7fb057c7b \
     --hash=sha256:c198e21b1289c2ab85ee4e67bb4b4ef3ead0892059901a8d5b622f24a1101e90
@@ -196,6 +202,7 @@ cryptography==42.0.8 \
     --hash=sha256:fa76fbb7596cc5839320000cdd5d0955313696d9511debab7ee7278fc8b5c84a \
     --hash=sha256:fff12c88a672ab9c9c1cf7b0c80e3ad9e2ebd9d828d955c126be4fd3e5578c9e
     # via
+    #   -r model_signing/install/requirements.in
     #   pyopenssl
     #   sigstore
 dnspython==2.6.1 \
@@ -231,6 +238,10 @@ idna==3.7 \
     # via
     #   email-validator
     #   requests
+in-toto-attestation==0.9.3 \
+    --hash=sha256:1f44d3f3bded1ed551e260c5e9f834ee05de03f1d2f360bada5a172c11d748ff \
+    --hash=sha256:cc0cf97417d94953b9fee6e9d415a11c59b4d47cee4f13746ffe935b28e3e8c4
+    # via -r model_signing/install/requirements.in
 markdown-it-py==3.0.0 \
     --hash=sha256:355216845c60bd96232cd8d8c40e8f9765cc86f46880e43a8fd22dc1a1a8cab1 \
     --hash=sha256:e3f60a94fa066dc52ec76661e37c851cb232d92f9886b15cb560aaada2df8feb
@@ -335,6 +346,21 @@ platformdirs==4.2.2 \
     --hash=sha256:2d7a1657e36a80ea911db832a8a6ece5ee53d8de21edd5cc5879af6530b1bfee \
     --hash=sha256:38b7b51f512eed9e84a22788b4bce1de17c0adb134d6becb09836e37d8654cd3
     # via sigstore
+protobuf==5.27.2 \
+    --hash=sha256:0e341109c609749d501986b835f667c6e1e24531096cff9d34ae411595e26505 \
+    --hash=sha256:176c12b1f1c880bf7a76d9f7c75822b6a2bc3db2d28baa4d300e8ce4cde7409b \
+    --hash=sha256:354d84fac2b0d76062e9b3221f4abbbacdfd2a4d8af36bab0474f3a0bb30ab38 \
+    --hash=sha256:4fadd8d83e1992eed0248bc50a4a6361dc31bcccc84388c54c86e530b7f58863 \
+    --hash=sha256:54330f07e4949d09614707c48b06d1a22f8ffb5763c159efd5c0928326a91470 \
+    --hash=sha256:610e700f02469c4a997e58e328cac6f305f649826853813177e6290416e846c6 \
+    --hash=sha256:7fc3add9e6003e026da5fc9e59b131b8f22b428b991ccd53e2af8071687b4fce \
+    --hash=sha256:9e8f199bf7f97bd7ecebffcae45ebf9527603549b2b562df0fbc6d4d688f14ca \
+    --hash=sha256:a109916aaac42bff84702fb5187f3edadbc7c97fc2c99c5ff81dd15dcce0d1e5 \
+    --hash=sha256:b848dbe1d57ed7c191dfc4ea64b8b004a3f9ece4bf4d0d80a367b76df20bf36e \
+    --hash=sha256:f3ecdef226b9af856075f28227ff2c90ce3a594d092c39bee5513573f25e2714
+    # via
+    #   -r model_signing/install/requirements.in
+    #   in-toto-attestation
 psutil==6.0.0 \
     --hash=sha256:02b69001f44cc73c1c5279d02b30a817e339ceb258ad75997325e0e6169d8b35 \
     --hash=sha256:1287c2b95f1c0a364d23bc6f2ea2365a8d4d9b726a3be7294296ff7ba97c17f0 \
@@ -471,7 +497,9 @@ pyjwt==2.8.0 \
 pyopenssl==24.1.0 \
     --hash=sha256:17ed5be5936449c5418d1cd269a1a9e9081bc54c17aed272b45856a3d3dc86ad \
     --hash=sha256:cabed4bfaa5df9f1a16c0ef64a0cb65318b5cd077a7eda7d6970131ca2f41a6f
-    # via sigstore
+    # via
+    #   -r model_signing/install/requirements.in
+    #   sigstore
 python-dateutil==2.9.0.post0 \
     --hash=sha256:37dd54208da7e1cd875388217d5e00ebd4179249f90fb72437e91a35459a0ad3 \
     --hash=sha256:a8b2bc7bffae282281c8140a97d3aa9c14da0b136dfe83f850eea9a5f7470427
@@ -502,7 +530,9 @@ sigstore==3.0.0 \
 sigstore-protobuf-specs==0.3.2 \
     --hash=sha256:50c99fa6747a3a9c5c562a43602cf76df0b199af28f0e9d4319b6775630425ea \
     --hash=sha256:cae041b40502600b8a633f43c257695d0222a94efa1e5110a7ec7ada78c39d99
-    # via sigstore
+    # via
+    #   -r model_signing/install/requirements.in
+    #   sigstore
 sigstore-rekor-types==0.0.13 \
     --hash=sha256:377fee942d5fc66437a4f54599472157149affaece9bbc7deb05e5b42f34ceba \
     --hash=sha256:63e9306a26931ed74411911948c250da7c5adc51c53507227738170424e6ae2d

model_signing/install/requirements_Linux.txt

@@ -4,14 +4,20 @@
 #
 #    pip-compile --generate-hashes --output-file=model_signing/install/requirements_Linux.txt --strip-extras model_signing/install/requirements.in
 #
+absl-py==2.1.0 \
+    --hash=sha256:526a04eadab8b4ee719ce68f204172ead1027549089702d99b9059f129ff1308 \
+    --hash=sha256:7820790efbb316739cde8b4e19357243fc3608a152024288513dd968d7d959ff
+    # via -r model_signing/install/requirements.in
 annotated-types==0.7.0 \
     --hash=sha256:1f02e8b43a8fbbc3f3e0d4f0f4bfc8131bcb4eebe8849b8e5c773f3a1c582a53 \
     --hash=sha256:aff07c09a53a08bc8cfccb9c85b05f1aa9a2a6f23728d790723543408344ce89
     # via pydantic
 betterproto==2.0.0b6 \
     --hash=sha256:720ae92697000f6fcf049c69267d957f0871654c8b0d7458906607685daee784 \
     --hash=sha256:a0839ec165d110a69d0d116f4d0e2bec8d186af4db826257931f0831dab73fcf
-    # via sigstore-protobuf-specs
+    # via
+    #   -r model_signing/install/requirements.in
+    #   sigstore-protobuf-specs
 certifi==2024.7.4 \
     --hash=sha256:5a1e7645bc0ec61a09e26c36f6106dd4cf40c6db3a1fb6352b0244e7fb057c7b \
     --hash=sha256:c198e21b1289c2ab85ee4e67bb4b4ef3ead0892059901a8d5b622f24a1101e90
@@ -196,6 +202,7 @@ cryptography==42.0.8 \
     --hash=sha256:fa76fbb7596cc5839320000cdd5d0955313696d9511debab7ee7278fc8b5c84a \
     --hash=sha256:fff12c88a672ab9c9c1cf7b0c80e3ad9e2ebd9d828d955c126be4fd3e5578c9e
     # via
+    #   -r model_signing/install/requirements.in
     #   pyopenssl
     #   sigstore
 dnspython==2.6.1 \
@@ -231,6 +238,10 @@ idna==3.7 \
     # via
     #   email-validator
     #   requests
+in-toto-attestation==0.9.3 \
+    --hash=sha256:1f44d3f3bded1ed551e260c5e9f834ee05de03f1d2f360bada5a172c11d748ff \
+    --hash=sha256:cc0cf97417d94953b9fee6e9d415a11c59b4d47cee4f13746ffe935b28e3e8c4
+    # via -r model_signing/install/requirements.in
 markdown-it-py==3.0.0 \
     --hash=sha256:355216845c60bd96232cd8d8c40e8f9765cc86f46880e43a8fd22dc1a1a8cab1 \
     --hash=sha256:e3f60a94fa066dc52ec76661e37c851cb232d92f9886b15cb560aaada2df8feb
@@ -335,6 +346,21 @@ platformdirs==4.2.2 \
     --hash=sha256:2d7a1657e36a80ea911db832a8a6ece5ee53d8de21edd5cc5879af6530b1bfee \
     --hash=sha256:38b7b51f512eed9e84a22788b4bce1de17c0adb134d6becb09836e37d8654cd3
     # via sigstore
+protobuf==5.27.2 \
+    --hash=sha256:0e341109c609749d501986b835f667c6e1e24531096cff9d34ae411595e26505 \
+    --hash=sha256:176c12b1f1c880bf7a76d9f7c75822b6a2bc3db2d28baa4d300e8ce4cde7409b \
+    --hash=sha256:354d84fac2b0d76062e9b3221f4abbbacdfd2a4d8af36bab0474f3a0bb30ab38 \
+    --hash=sha256:4fadd8d83e1992eed0248bc50a4a6361dc31bcccc84388c54c86e530b7f58863 \
+    --hash=sha256:54330f07e4949d09614707c48b06d1a22f8ffb5763c159efd5c0928326a91470 \
+    --hash=sha256:610e700f02469c4a997e58e328cac6f305f649826853813177e6290416e846c6 \
+    --hash=sha256:7fc3add9e6003e026da5fc9e59b131b8f22b428b991ccd53e2af8071687b4fce \
+    --hash=sha256:9e8f199bf7f97bd7ecebffcae45ebf9527603549b2b562df0fbc6d4d688f14ca \
+    --hash=sha256:a109916aaac42bff84702fb5187f3edadbc7c97fc2c99c5ff81dd15dcce0d1e5 \
+    --hash=sha256:b848dbe1d57ed7c191dfc4ea64b8b004a3f9ece4bf4d0d80a367b76df20bf36e \
+    --hash=sha256:f3ecdef226b9af856075f28227ff2c90ce3a594d092c39bee5513573f25e2714
+    # via
+    #   -r model_signing/install/requirements.in
+    #   in-toto-attestation
 psutil==6.0.0 \
     --hash=sha256:02b69001f44cc73c1c5279d02b30a817e339ceb258ad75997325e0e6169d8b35 \
     --hash=sha256:1287c2b95f1c0a364d23bc6f2ea2365a8d4d9b726a3be7294296ff7ba97c17f0 \
@@ -471,7 +497,9 @@ pyjwt==2.8.0 \
 pyopenssl==24.1.0 \
     --hash=sha256:17ed5be5936449c5418d1cd269a1a9e9081bc54c17aed272b45856a3d3dc86ad \
     --hash=sha256:cabed4bfaa5df9f1a16c0ef64a0cb65318b5cd077a7eda7d6970131ca2f41a6f
-    # via sigstore
+    # via
+    #   -r model_signing/install/requirements.in
+    #   sigstore
 python-dateutil==2.9.0.post0 \
     --hash=sha256:37dd54208da7e1cd875388217d5e00ebd4179249f90fb72437e91a35459a0ad3 \
     --hash=sha256:a8b2bc7bffae282281c8140a97d3aa9c14da0b136dfe83f850eea9a5f7470427
@@ -502,7 +530,9 @@ sigstore==3.0.0 \
 sigstore-protobuf-specs==0.3.2 \
     --hash=sha256:50c99fa6747a3a9c5c562a43602cf76df0b199af28f0e9d4319b6775630425ea \
     --hash=sha256:cae041b40502600b8a633f43c257695d0222a94efa1e5110a7ec7ada78c39d99
-    # via sigstore
+    # via
+    #   -r model_signing/install/requirements.in
+    #   sigstore
 sigstore-rekor-types==0.0.13 \
     --hash=sha256:377fee942d5fc66437a4f54599472157149affaece9bbc7deb05e5b42f34ceba \
     --hash=sha256:63e9306a26931ed74411911948c250da7c5adc51c53507227738170424e6ae2d

model_signing/install/requirements_Windows.txt

@@ -4,14 +4,20 @@
 #
 #    pip-compile --generate-hashes --output-file=model_signing/install/requirements_Windows.txt --strip-extras model_signing/install/requirements.in
 #
+absl-py==2.1.0 \
+    --hash=sha256:526a04eadab8b4ee719ce68f204172ead1027549089702d99b9059f129ff1308 \
+    --hash=sha256:7820790efbb316739cde8b4e19357243fc3608a152024288513dd968d7d959ff
+    # via -r model_signing/install/requirements.in
 annotated-types==0.7.0 \
     --hash=sha256:1f02e8b43a8fbbc3f3e0d4f0f4bfc8131bcb4eebe8849b8e5c773f3a1c582a53 \
     --hash=sha256:aff07c09a53a08bc8cfccb9c85b05f1aa9a2a6f23728d790723543408344ce89
     # via pydantic
 betterproto==2.0.0b6 \
     --hash=sha256:720ae92697000f6fcf049c69267d957f0871654c8b0d7458906607685daee784 \
     --hash=sha256:a0839ec165d110a69d0d116f4d0e2bec8d186af4db826257931f0831dab73fcf
-    # via sigstore-protobuf-specs
+    # via
+    #   -r model_signing/install/requirements.in
+    #   sigstore-protobuf-specs
 certifi==2024.7.4 \
     --hash=sha256:5a1e7645bc0ec61a09e26c36f6106dd4cf40c6db3a1fb6352b0244e7fb057c7b \
     --hash=sha256:c198e21b1289c2ab85ee4e67bb4b4ef3ead0892059901a8d5b622f24a1101e90
@@ -196,6 +202,7 @@ cryptography==42.0.8 \
     --hash=sha256:fa76fbb7596cc5839320000cdd5d0955313696d9511debab7ee7278fc8b5c84a \
     --hash=sha256:fff12c88a672ab9c9c1cf7b0c80e3ad9e2ebd9d828d955c126be4fd3e5578c9e
     # via
+    #   -r model_signing/install/requirements.in
     #   pyopenssl
     #   sigstore
 dnspython==2.6.1 \
@@ -231,6 +238,10 @@ idna==3.7 \
     # via
     #   email-validator
     #   requests
+in-toto-attestation==0.9.3 \
+    --hash=sha256:1f44d3f3bded1ed551e260c5e9f834ee05de03f1d2f360bada5a172c11d748ff \
+    --hash=sha256:cc0cf97417d94953b9fee6e9d415a11c59b4d47cee4f13746ffe935b28e3e8c4
+    # via -r model_signing/install/requirements.in
 markdown-it-py==3.0.0 \
     --hash=sha256:355216845c60bd96232cd8d8c40e8f9765cc86f46880e43a8fd22dc1a1a8cab1 \
     --hash=sha256:e3f60a94fa066dc52ec76661e37c851cb232d92f9886b15cb560aaada2df8feb
@@ -335,6 +346,21 @@ platformdirs==4.2.2 \
     --hash=sha256:2d7a1657e36a80ea911db832a8a6ece5ee53d8de21edd5cc5879af6530b1bfee \
     --hash=sha256:38b7b51f512eed9e84a22788b4bce1de17c0adb134d6becb09836e37d8654cd3
     # via sigstore
+protobuf==5.27.2 \
+    --hash=sha256:0e341109c609749d501986b835f667c6e1e24531096cff9d34ae411595e26505 \
+    --hash=sha256:176c12b1f1c880bf7a76d9f7c75822b6a2bc3db2d28baa4d300e8ce4cde7409b \
+    --hash=sha256:354d84fac2b0d76062e9b3221f4abbbacdfd2a4d8af36bab0474f3a0bb30ab38 \
+    --hash=sha256:4fadd8d83e1992eed0248bc50a4a6361dc31bcccc84388c54c86e530b7f58863 \
+    --hash=sha256:54330f07e4949d09614707c48b06d1a22f8ffb5763c159efd5c0928326a91470 \
+    --hash=sha256:610e700f02469c4a997e58e328cac6f305f649826853813177e6290416e846c6 \
+    --hash=sha256:7fc3add9e6003e026da5fc9e59b131b8f22b428b991ccd53e2af8071687b4fce \
+    --hash=sha256:9e8f199bf7f97bd7ecebffcae45ebf9527603549b2b562df0fbc6d4d688f14ca \
+    --hash=sha256:a109916aaac42bff84702fb5187f3edadbc7c97fc2c99c5ff81dd15dcce0d1e5 \
+    --hash=sha256:b848dbe1d57ed7c191dfc4ea64b8b004a3f9ece4bf4d0d80a367b76df20bf36e \
+    --hash=sha256:f3ecdef226b9af856075f28227ff2c90ce3a594d092c39bee5513573f25e2714
+    # via
+    #   -r model_signing/install/requirements.in
+    #   in-toto-attestation
 psutil==6.0.0 \
     --hash=sha256:02b69001f44cc73c1c5279d02b30a817e339ceb258ad75997325e0e6169d8b35 \
     --hash=sha256:1287c2b95f1c0a364d23bc6f2ea2365a8d4d9b726a3be7294296ff7ba97c17f0 \
@@ -471,7 +497,9 @@ pyjwt==2.8.0 \
 pyopenssl==24.1.0 \
     --hash=sha256:17ed5be5936449c5418d1cd269a1a9e9081bc54c17aed272b45856a3d3dc86ad \
     --hash=sha256:cabed4bfaa5df9f1a16c0ef64a0cb65318b5cd077a7eda7d6970131ca2f41a6f
-    # via sigstore
+    # via
+    #   -r model_signing/install/requirements.in
+    #   sigstore
 python-dateutil==2.9.0.post0 \
     --hash=sha256:37dd54208da7e1cd875388217d5e00ebd4179249f90fb72437e91a35459a0ad3 \
     --hash=sha256:a8b2bc7bffae282281c8140a97d3aa9c14da0b136dfe83f850eea9a5f7470427
@@ -502,7 +530,9 @@ sigstore==3.0.0 \
 sigstore-protobuf-specs==0.3.2 \
     --hash=sha256:50c99fa6747a3a9c5c562a43602cf76df0b199af28f0e9d4319b6775630425ea \
     --hash=sha256:cae041b40502600b8a633f43c257695d0222a94efa1e5110a7ec7ada78c39d99
-    # via sigstore
+    # via
+    #   -r model_signing/install/requirements.in
+    #   sigstore
 sigstore-rekor-types==0.0.13 \
     --hash=sha256:377fee942d5fc66437a4f54599472157149affaece9bbc7deb05e5b42f34ceba \
     --hash=sha256:63e9306a26931ed74411911948c250da7c5adc51c53507227738170424e6ae2d

model_signing/install/requirements_dev_Darwin.txt

@@ -186,13 +186,13 @@ ninja==1.11.1.1 \
     --hash=sha256:ecf80cf5afd09f14dcceff28cb3f11dc90fb97c999c89307aea435889cb66877 \
     --hash=sha256:fa2ba9d74acfdfbfbcf06fad1b8282de8a7a8c481d9dee45c859a8c93fcc1082
     # via pytype
+pycnite==2024.7.9 \
+    --hash=sha256:aece401e70e8b6bf369b3b33867c79a1b8bf584e68da9790de2f821503cebcf8 \
+    --hash=sha256:f07bea393ee4d5820013fae66db6cc091e8dc01fd3f6b367595108752f264872
 platformdirs==4.2.2 \
     --hash=sha256:2d7a1657e36a80ea911db832a8a6ece5ee53d8de21edd5cc5879af6530b1bfee \
     --hash=sha256:38b7b51f512eed9e84a22788b4bce1de17c0adb134d6becb09836e37d8654cd3
     # via pylint
-pycnite==2024.6.28 \
-    --hash=sha256:228b2cfae86fecc82e1bddb2b44b4890b337e0a778c1521a56546642dd28bfe4 \
-    --hash=sha256:e3f1f9697b49af8d4edc0e0d228b23fdfc56acc7878bc64378e46ddf8150d3a8
     # via pytype
 pydot==2.0.0 \
     --hash=sha256:408a47913ea7bd5d2d34b274144880c1310c4aee901f353cf21fe2e526a4ea28 \

model_signing/install/requirements_dev_Linux.txt

@@ -186,14 +186,13 @@ ninja==1.11.1.1 \
     --hash=sha256:ecf80cf5afd09f14dcceff28cb3f11dc90fb97c999c89307aea435889cb66877 \
     --hash=sha256:fa2ba9d74acfdfbfbcf06fad1b8282de8a7a8c481d9dee45c859a8c93fcc1082
     # via pytype
+pycnite==2024.7.9 \
+    --hash=sha256:aece401e70e8b6bf369b3b33867c79a1b8bf584e68da9790de2f821503cebcf8 \
+    --hash=sha256:f07bea393ee4d5820013fae66db6cc091e8dc01fd3f6b367595108752f264872
 platformdirs==4.2.2 \
     --hash=sha256:2d7a1657e36a80ea911db832a8a6ece5ee53d8de21edd5cc5879af6530b1bfee \
     --hash=sha256:38b7b51f512eed9e84a22788b4bce1de17c0adb134d6becb09836e37d8654cd3
     # via pylint
-pycnite==2024.6.28 \
-    --hash=sha256:228b2cfae86fecc82e1bddb2b44b4890b337e0a778c1521a56546642dd28bfe4 \
-    --hash=sha256:e3f1f9697b49af8d4edc0e0d228b23fdfc56acc7878bc64378e46ddf8150d3a8
-    # via pytype
 pydot==2.0.0 \
     --hash=sha256:408a47913ea7bd5d2d34b274144880c1310c4aee901f353cf21fe2e526a4ea28 \
     --hash=sha256:60246af215123fa062f21cd791be67dda23a6f280df09f68919e637a1e4f3235

model_signing/signature/__init__.py

@@ -0,0 +1,13 @@
+# Copyright (c) 2024, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.

model_signing/signature/encoding.py

@@ -0,0 +1,38 @@
+# Copyright (c) 2024, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from google.protobuf import json_format
+from in_toto_attestation.v1 import statement_pb2 as statement_pb
+
+PAYLOAD_TYPE = "application/vnd.in-toto+json"
+
+
+def pae(statement: statement_pb.Statement) -> bytes:
+    """Generates the PAE encoding of the statement.
+
+    See https://github.com/secure-systems-lab/dsse/blob/v1.0.0/protocol.md
+    for details.
+
+    Args:
+        statement (statement_pb.Statement): the statement to be encoded.
+
+    Returns:
+        bytes: the encoded statement as bytes.
+    """
+    enc_payload = json_format.MessageToJson(statement).encode()
+    payload_len = len(enc_payload)
+    pae = ('DSSEV1'
+           f' {len(PAYLOAD_TYPE)} {PAYLOAD_TYPE}'
+           f' {payload_len} {enc_payload}')
+    pae = pae.encode()
+    return pae