The attestation verifier verifies attestations provided by the attestation server containing a secp256k1 public key and signs the response using its own secp256k1 key. Intended to be run inside an enclave to provide cheap attestation verification services.
Once the attestation of the verifier is verified on-chain (very expensive), it enables other enclaves, including other verifiers, to get verified by submitting a simple ECDSA signature from the verifier instead (very cheap). The process essentially extends the chain of trust of the attestation verifier enclave instead of trying to verify the full attestation of the other enclave again.
cargo build --releaseReproducible builds can be done using Nix. The monorepo provides a Nix flake which includes this project and can be used to trigger builds:
nix build -v .#<flavor>.attestation.verifier.<output>Supported flavors:
gnumusl
Supported outputs:
default, same ascompresseduncompressedcompressed, usingupx
$ ./target/release/oyster-attestation-verifier --help
Usage: oyster-attestation-verifier --secp256k1-secret <SECP256K1_SECRET> --secp256k1-public <SECP256K1_PUBLIC> --ip <IP> --port <PORT>
Options:
--secp256k1-secret <SECP256K1_SECRET>
path to secp256k1 private key file (e.g. /app/secp256k1.sec)
--secp256k1-public <SECP256K1_PUBLIC>
path to secp256k1 public key file (e.g. /app/secp256k1.pub)
-i, --ip <IP>
server ip (e.g. 127.0.0.1)
-p, --port <PORT>
server port (e.g. 1400)
-h, --help
Print help
-V, --version
Print version
The attestation verifier also includes a binary to verify an attestation doc locally through the CLI as shown below :-
$ ./target/release/oyster-verify-attestation --help
Usage: oyster-verify-attestation --attestation <ATTESTATION>
Options:
--attestation <ATTESTATION>
path to attestation doc hex string file
-h, --help Print help
-V, --version Print version
Above execution will return an error if failing to parse or verify the attestation doc/file. If the verification completes successfully, the parsed attestation doc will be printed in below format :-
AttestationDecoded {
pcrs: [[...], [...], [...]],
timestamp: '...',
public_key: [...]
}
To generate the attestation hex file, call the corresponding attestation-server endpoint inside a running enclave like below:-
$ curl <attestation_server_ip:attestation_server_port>/attestation/hex --output attestation.hex
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 8938 100 8938 0 0 126k 0 --:--:-- --:--:-- --:--:-- 124k
The attestation verifier exposes two verification endpoints which expect the attestation in one of two formats - raw and hex. The formats match the two endpoints of the attestation server and the response of the server can just be sent to the verifier as is.
/verify/raw
$ curl <attestation_server_ip:attestation_server_port>/attestation/raw -vs | curl -H "Content-Type: application/octet-stream" --data-binary @- <attestation_verifier_ip:attestation_verifier_port>/verify/raw -vs
* Trying <attestation_server_ip:attestation_server_port>...
* Connected to <attestation_server_ip> (<attestation_server_ip>) port <attestation_server_port> (#0)
> GET /attestation/raw HTTP/1.1
> Host: <attestation_server_ip:attestation_server_port>
> User-Agent: curl/7.81.0
> Accept: */*
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< content-type: application/octet-stream
< content-length: 4468
< date: Sun, 07 Apr 2024 06:36:44 GMT
<
{ [2682 bytes data]
* Connection #0 to host <attestation_server_ip> left intact
* Trying <attestation_verifier_ip:attestation_verifier_port>...
* Connected to <attestation_verifier_ip> (<attestation_verifier_ip>) port <attestation_verifier_port> (#0)
> POST /verify/raw HTTP/1.1
> Host: <attestation_verifier_ip:attestation_verifier_port>
> User-Agent: curl/7.81.0
> Accept: */*
> Content-Type: application/octet-stream
> Content-Length: 4468
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< content-length: 799
< content-type: application/json
< date: Sun, 07 Apr 2024 06:36:44 GMT
<
* Connection #0 to host <attestation_verifier_ip> left intact
{"signature":"1aaffb1463cfbeb24401267d2ab2661a9695dd0fb294fc4f4e66ad98efa1ece63b79c0bfc5d79c8515abbfb4fa50994b848132d3374821ff09eb22c7af37395e1b","secp256k1_public":"e646f8b0071d5ba75931402522cc6a5c42a84a6fea238864e5ac9a0e12d83bd36d0c8109d3ca2b699fce8d082bf313f5d2ae249bb275b6b6e91e0fcd9262f4bb","pcr0":"189038eccf28a3a098949e402f3b3d86a876f4915c5b02d546abb5d8c507ceb1755b8192d8cfca66e8f226160ca4c7a6","pcr1":"5d3938eb05288e20a981038b1861062ff4174884968a39aee5982b312894e60561883576cc7381d1a7d05b809936bd16","pcr2":"6c3ef363c488a9a86faa63a44653fd806e645d4540b40540876f3b811fc1bceecf036a4703f07587c501ee45bb56a1aa","timestamp":1712471793488,"verifier_secp256k1_public":"e646f8b0071d5ba75931402522cc6a5c42a84a6fea238864e5ac9a0e12d83bd36d0c8109d3ca2b699fce8d082bf313f5d2ae249bb275b6b6e91e0fcd9262f4bb"}
/attestation/hex
$ curl <attestation_server_ip:attestation_server_port>/attestation/hex -vs | curl -H "Content-Type: text/plain" -d @- <attestation_verifier_ip:attestation_verifier_port>/verify/hex -vs
* Trying <attestation_server_ip:attestation_server_port>...
* Connected to <attestation_server_ip> (<attestation_server_ip>) port <attestation_server_port> (#0)
> GET /attestation/hex HTTP/1.1
> Host: <attestation_server_ip:attestation_server_port>
> User-Agent: curl/7.81.0
> Accept: */*
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< content-type: text/plain; charset=utf-8
< content-length: 8936
< date: Sun, 07 Apr 2024 06:44:25 GMT
<
{ [2681 bytes data]
* Connection #0 to host <attestation_server_ip> left intact
* Trying <attestation_verifier_ip:attestation_verifier_port>...
* Connected to <attestation_verifier_ip> (<attestation_verifier_ip>) port <attestation_verifier_port> (#0)
> POST /verify/hex HTTP/1.1
> Host: <attestation_verifier_ip:attestation_verifier_port>
> User-Agent: curl/7.81.0
> Accept: */*
> Content-Type: text/plain
> Content-Length: 8936
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< content-length: 799
< content-type: application/json
< date: Sun, 07 Apr 2024 06:44:25 GMT
<
* Connection #0 to host <attestation_verifier_ip> left intact
{"signature":"4ed49c703e8deea8dabccbeeb8fe5625776dbbbef4cffbb9c31f84d21e7a0b6c63707aade102548cc05e6de3a49469b96c700f5b8709e75ec050061ac69dbb621c","secp256k1_public":"e646f8b0071d5ba75931402522cc6a5c42a84a6fea238864e5ac9a0e12d83bd36d0c8109d3ca2b699fce8d082bf313f5d2ae249bb275b6b6e91e0fcd9262f4bb","pcr0":"189038eccf28a3a098949e402f3b3d86a876f4915c5b02d546abb5d8c507ceb1755b8192d8cfca66e8f226160ca4c7a6","pcr1":"5d3938eb05288e20a981038b1861062ff4174884968a39aee5982b312894e60561883576cc7381d1a7d05b809936bd16","pcr2":"6c3ef363c488a9a86faa63a44653fd806e645d4540b40540876f3b811fc1bceecf036a4703f07587c501ee45bb56a1aa","timestamp":1712472254392,"verifier_secp256k1_public":"e646f8b0071d5ba75931402522cc6a5c42a84a6fea238864e5ac9a0e12d83bd36d0c8109d3ca2b699fce8d082bf313f5d2ae249bb275b6b6e91e0fcd9262f4bb"}
{
"signature": "...",
"secp256k1_public": "...",
"pcr0": "...",
"pcr1": "...",
"pcr2": "...",
"timestamp": ...,
"verifier_secp256k1_public": "..."
}The verifier responds with JSON with the following fields:
signature: signature provided by the verifiersecp256k1_public: public key that was encoded in the attestationpcr0: PCR0 that was encoded in the attestationpcr1: PCR1 that was encoded in the attestationpcr2: PCR2 that was encoded in the attestationtimestamp: timestamp that was encoded in the attestationverifier_secp256k1_public: public key of the verifier corresponding to the signature
The verifier creates the signature as per the EIP-712 standard.
struct EIP712Domain {
string name = "marlin.oyster.AttestationVerifier",
string version = "1",
}The chainId, verifyingContract and salt fields are omitted because we do not see any significant replay concerns in allowing the signature to be verified on any contract on any chain.
struct Attestation {
bytes enclavePubKey;
bytes PCR0;
bytes PCR1;
bytes PCR2;
uint256 timestampInMilliseconds;
}It is designed to be verified by the following solidity code (taken from the AttestationVerifier contract):
bytes32 private constant DOMAIN_SEPARATOR =
keccak256(
abi.encode(
keccak256("EIP712Domain(string name,string version)"),
keccak256("marlin.oyster.AttestationVerifier"),
keccak256("1")
)
);
bytes32 private constant ATTESTATION_TYPEHASH =
keccak256("Attestation(bytes enclavePubKey,bytes PCR0,bytes PCR1,bytes PCR2,uint256 timestampInMilliseconds)");
function _verify(bytes memory signature, Attestation memory attestation) internal view {
bytes32 hashStruct = keccak256(
abi.encode(
ATTESTATION_TYPEHASH,
keccak256(attestation.enclavePubKey),
keccak256(attestation.PCR0),
keccak256(attestation.PCR1),
keccak256(attestation.PCR2),
attestation.timestampInMilliseconds
)
);
bytes32 digest = keccak256(abi.encodePacked("\x19\x01", DOMAIN_SEPARATOR, hashStruct));
address signer = ECDSA.recover(digest, signature);
...
}Before pushing any changes, try to make sure that no existing functionalities are breaking by running the unit tests. Tests require fresh attestation so update the sample data present in src/test/ directory by interacting with a running oyster enclave's attestation server (as described above).
cargo test