Commitment Mapper

Made by Sismo

Commitment Mapper

The commitment mapper is an off-chain trusted service provided by Sismo.

It enables account owners to convert a proof of account ownership into a proof of secret knowledge.

The account owner receives a receipt from the Commitment Mapper, which maps their account with their commitment (e.g hash of their secret). The commitment mapper ensures that only one commitment can be associated to an account.

The combination of the user's secret and the commitment mapper receipt form the Delegated Proof Of Ownership.

You will find more information in the documentation.

Public keys

Hydra Delegated Proof Of Ownership

URI: https://x5y521b36b.execute-api.eu-west-1.amazonaws.com
EdDSAPubKey:
- X: 0x0c6c16efc72c198f4549bd069f1e57f091885234b9c140286d80ef431151d644
- Y: 0x12c54731563d974ead25d469d2263fdf0e230d5a09f6cd40a06e60210610d642

Commitment mapper implementations

The commitment mapper can have multiple implementations where the signature algorithm from the commitment mapper varies. The map which stores the commitments is then namespaced for each type of implementation.

Hydra

Specification

The Hydra was designed for an easy verification inside a Snark Circuit. Its specifications are:

Signature algorithm: EdDSA using poseidon hash function and the BabyJubJub elliptic curve.
CommitmentReceipt = Signature(PoseidonHash(Ethereum Address, Commitment))

A commitment is generated based on the following specification:

Commitment = PoseidonHash(secret), where the secret is a random number choosen by the user and hashed in the browser.

The Poseidon hash algorithm makes the commitmentReceipt easy to verify inside a snark circuit (~ 5000 constraints). That means a snark circuit can easily verify that a specific secret is only known by the owner of an Ethereum Address. This secret then acts as a proof of ownership for the Ethereum Address.

API Endpoint

Commit Ethereum account

Endpoint: https://x5y521b36b.execute-api.eu-west-1.amazonaws.com/commit-ethereum-eddsa

Method: POST

Parameters:

ethAddress : Ethereum Address to map with the commitment
ethSignature : Signature of this message by the Ethereum Address to prove the ownership
commitment : The commitment choosen by the user

Response:

commitmentMapperPubKey : The EdDSA public key of the commitment Mapper. This public key will never change.
commitmentReceipt : The Signature(HashPoseidon(EthereumAddress, Commitment))

Example:

$ curl -X POST -H 'content-type: application/json' https://x5y521b36b.execute-api.eu-west-1.amazonaws.com/commit-ethereum-eddsa -d @- <<EOF
{
    "ethAddress": "0x41ea85211c08227bd62b03f3efc65faaa6cbd1c3",
    "ethSignature": "0xa6c615ef9ebe12168abe3ab17cb99e0a134b9b037425637f09107bd964d1da34264b23b25edd75b15bde9819d4ac8a8395ec4ffe7401a21946680890bbbe0c1a1b",
    "commitment": "0x25a80aa8b7c619ed19da7ae54286b77fd705d2c01fcf974ab1cb3a902f8e3f89"
}
EOF

{
  "commitmentMapperPubKey": [
    "0x0c6c16efc72c198f4549bd069f1e57f091885234b9c140286d80ef431151d644",
    "0x12c54731563d974ead25d469d2263fdf0e230d5a09f6cd40a06e60210610d642"
  ],
  "commitmentReceipt": [
    "0x2b17f369369670bef2212c4e0250e8be06d0d1c8bb687b5d61b1c235e1f5fc96",
    "0x26c89da29c3c5f05eb40ddaa440bd7d2bb2d5be73211ae58c664aa0020a09914",
    "0x025b5f8dc6d4b1865c77e04954704ea26ba0e0a9dc62d8bc2f8b84ad3348ca54"
  ]
}

Commit Github account

Endpoint: https://x5y521b36b.execute-api.eu-west-1.amazonaws.com/commit-github-eddsa

Method: POST

Parameters:

githubCode : Code sent by the OAuth SSO of github
commitment : The commitment choosen by the user

Response:

commitmentMapperPubKey : The EdDSA public key of the commitment Mapper. This public key will never change.
commitmentReceipt : The Signature(HashPoseidon(EthereumAddress, Commitment))
account : Detail of the github account that can be saved in the sismo vault
- login: github username
- profileId: github profile id
- name: github public name if set
- avatarUrl: github link to the avatar
- identifier: 0x100100...000{id} padded address to be used inside sismo groups of account

Example:

$ curl -X POST -H 'content-type: application/json' https://x5y521b36b.execute-api.eu-west-1.amazonaws.com/commit-github-eddsa -d @- <<EOF
{
    "githubCode": "11c08227bd62b03f3efc65faaa6",
    "commitment": "0x25a80aa8b7c619ed19da7ae54286b77fd705d2c01fcf974ab1cb3a902f8e3f89"
}
EOF

{
  "commitmentMapperPubKey": [
    "0x0c6c16efc72c198f4549bd069f1e57f091885234b9c140286d80ef431151d644",
    "0x12c54731563d974ead25d469d2263fdf0e230d5a09f6cd40a06e60210610d642"
  ],
  "commitmentReceipt": [
    "0x2b17f369369670bef2212c4e0250e8be06d0d1c8bb687b5d61b1c235e1f5fc96",
    "0x26c89da29c3c5f05eb40ddaa440bd7d2bb2d5be73211ae58c664aa0020a09914",
    "0x025b5f8dc6d4b1865c77e04954704ea26ba0e0a9dc62d8bc2f8b84ad3348ca54"
  ],
  "account": {
    "login": "leosayous21",
    "profileId": 11630545,
    "name": "Léo sayous",
    "avatarUrl": "https://avatars.githubusercontent.com/u/11630545?v=4",
    "identifier": "0x1001000000000000000000000000000011630545"
  }
}

Commit Twitter account

The commit twitter account is in 2 phases: First the request token route for the OAuth2 with twitter. Then the commit twitter eddsa route that let register a commitment for a specific twitter account.

Endpoint: https://x5y521b36b.execute-api.eu-west-1.amazonaws.com/request-twitter-token

Method: GET

Query params:

oauth_callback : The oauth callback to redirect the user when interacting with twitter

Response:

code: 302
Location Header: https://api.twitter.com/oauth/authenticate?oauth_token=${requestToken}

Endpoint: https://x5y521b36b.execute-api.eu-west-1.amazonaws.com/commit-twitter-eddsa

Method: POST

Parameters:

oauthToken : Code sent by the OAuth SSO of Twitter after having interacted with the twitter frontend
oauthVerifier : Code sent by the OAuth SSO of Twitter after having interacted with the twitter frontend
commitment : The commitment chosen by the user

Response:

commitmentMapperPubKey : The EdDSA public key of the commitment Mapper. This public key will never change.
commitmentReceipt : The Signature(HashPoseidon(AccountIdentifier, Commitment))
account : Detail of the twitter account that can be saved in the sismo vault
- username: twitter username
- userId: twitter profile id
- identifier: 0x100100...000{id} padded address to be used inside sismo groups of account

Example:

$ curl -X POST -H 'content-type: application/json' https://x5y521b36b.execute-api.eu-west-1.amazonaws.com/commit-twitter-eddsa -d @- <<EOF
{
    "oauthToken": "11c08227bd62b03f3efc65faaa6",
    "oauthVerifier": "11c08227bd62b03f3efc65faaa6"
}
EOF

{
  "commitmentMapperPubKey": [
    "0x0c6c16efc72c198f4549bd069f1e57f091885234b9c140286d80ef431151d644",
    "0x12c54731563d974ead25d469d2263fdf0e230d5a09f6cd40a06e60210610d642"
  ],
  "commitmentReceipt": [
    "0x2b17f369369670bef2212c4e0250e8be06d0d1c8bb687b5d61b1c235e1f5fc96",
    "0x26c89da29c3c5f05eb40ddaa440bd7d2bb2d5be73211ae58c664aa0020a09914",
    "0x025b5f8dc6d4b1865c77e04954704ea26ba0e0a9dc62d8bc2f8b84ad3348ca54"
  ],
  "account": {
    "login": "LeopoldSayous",
    "profileId": 11630545,
    "identifier": "0x1002000000000000000000000000000011630545"
  }
}

Sismo address

The commitmentReceipt fot the sismo address 0x0000000000000000000000000000000000515110 is automatically created. It serves for offchain services which want to use the ZKSMPS offchain verifier without a specific destination.
It can be retrieve with this endpoint:

Endpoint: https://x5y521b36b.execute-api.eu-west-1.amazonaws.com/sismo-address-commitment

Method: GET

Response:

commitmentMapperPubKey : The EdDSA public key of the commitment Mapper. This public key will never change.
commitmentReceipt : The Signature(HashPoseidon(EthereumAddress, Commitment))

Example:

curl https://x5y521b36b.execute-api.eu-west-1.amazonaws.com/sismo-address-commitment

{
  "commitmentMapperPubKey": [
    "0x0c6c16efc72c198f4549bd069f1e57f091885234b9c140286d80ef431151d644",
    "0x12c54731563d974ead25d469d2263fdf0e230d5a09f6cd40a06e60210610d642"
  ],
  "commitmentReceipt": [
    "0x0efc00005caca3317d85bcd00b52320f9206ab7b91eccd8bcbdf7a0b4a170073",
    "0x1627540d131244ef425588a0874c7e723af4ad0203700984c89cb79575ad6847",
    "0x01ed0e48f1d9ae09b9165f281e572e0c8df00b0599fa37fb34f42a4cdc169e95"
  ]
}

Deployed endpoints

staging: https://x5y521b36b.execute-api.eu-west-1.amazonaws.com
prod-v1: https://sibgc1bwn8.execute-api.eu-west-1.amazonaws.com
prod-beta: https://x93oogcd5e.execute-api.eu-west-1.amazonaws.com
dev-beta: https://btwu3bqo4a.execute-api.eu-west-1.amazonaws.com

Dev environment

Running the commitment mapper locally

Launch in dev mode on staging environment.

source .env.staging-beta.sh
yarn dev

Executing the tests

Running the docker container is required for a few tests to pass.

docker-compose -f docker-compose.test.yaml up
npx jest

License

Distributed under the MIT License.

Contribute

Please, feel free to open issues, PRs or simply provide feedback!

Contact

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sismo-core / sismo-commitment-mapper