Decrypt a ZelfProof

With this endpoint you can decrypt the content stored in the Zero Knowledge Face Proof provided by Zelf.

Endpoint

https://api.zelf.world/api/zelf-proof/decrypt

This endpoint is used to verify the raw hash bytes against a face, thereby decrypting the associated metadata.

Request

• Endpoint: /api/zelf-proof/decrypt

• Method: POST

• Content-Type: application/json

Body

The request body should be a JSON object containing the following fields:

{
  "faceBase64": "face_base_64_photo",
  "livenessLevel": "REGULAR",
  "os": "DESKTOP",
  "password": "(optional) password",
  "zelfProof": "<your_zelf_proof>",
  "verifierKey": "(optional) verifiers_auth_key"
}

Fields:

• faceBase64: string (Required) - Base64 encoded face image data that will be compared against the ZelfProof.

• livenessLevel: string (Optional) - Specifies the tolerance for face liveness checks. E.g., "REGULAR".

• os: string (Optional) - The operating system from where the request originates, e.g., "DESKTOP".

• password: string (Optional) - A password if required to decrypt the ZelfProof.

• zelfProof: string (Required) - The ZelfProof in base64 format that needs to be verified and decrypted.

• verifierKey: string (Optional) - An authentication key required for decrypting the ZelfProof if specified.

Responses

• 200 OK: The request was successful, and the decrypted data from the ZelfProof is returned in JSON format.

  {
    "publicData": {
      "variable1": "string",
      "variable2": "string",
      "variable3": "string"
    },
    "difficulty": "EASY",
    "faceCropBase64": "string",
    "metadata": {
      "mnemonic": "string",
      "variable2": "string",
      "variable3": "string"
    },
    "identifier": "string"
  }

• 400 Bad Request: There was an error with the request. Possible error codes include:

  {
    "code": "ERR_INVALID_IMAGE",
    "message": "Invalid base64 string for the face image."
  }

• 401 Unauthorized: The API Key is not present in the X-api-key header.

  {
    "code": "ERR_API_KEY_NOT_PRESENT",
    "message": "API Key must be present in the x-api-key header."
  }

• 403 Forbidden: The API Key is incorrect or there is an issue with licensing. Possible error codes include:

  • ERR_API_KEY_NOT_VALID: The provided API Key is not valid.

  • ERR_LICENSE_EXPIRED: The Zelf SDK license has expired.

  • ERR_CANNOT_CONNECT_TO_TIME_SERVER: Cannot connect to the time server to verify license expiry.

  • ERR_CANNOT_CONNECT_TO_HOME_SERVER: Cannot connect to the home server to verify license expiry.

  • ERR_NUMBER_OF_AVAILABLE_INSTANCES_EXCEEDED: The number of available instances for this license has been exceeded.

• 413 Payload Too Large: The request sent is too large. Reduce the size of the image or data.

  {
    "code": "ERR_PAYLOAD_IS_TOO_LARGE",
    "message": "The request sent is too big. Please try reducing the size of image(s)/data."
  }

• 422 Unprocessable Entity: The request is invalid due to a specific error related to its content.

  {
    "code": "ERR_UNPROCESSABLE_CONTENT",
    "message": "Invalid request: <specific message related to error>"
  }

Error Codes

Here are some specific error codes that might be returned during verification:

• ERR_INVALID_IMAGE: Invalid base64 string for the face image.

• ERR_NO_FACE_DETECTED: No face detected in the image.

• ERR_MULTIPLE_FACES_DETECTED: Multiple faces detected in the image.

• ERR_INVALID_ZELFPROOF_BYTES: The provided hash bytes could not be interpreted as a valid base64 string.

• ERR_PARSE_FAILED: The hash could not be interpreted as a valid hash.

• ERR_PASSWORD_REQUIRED: A password is required to decrypt the hash but was not provided.

• ERR_INVALID_PASSWORD: The provided password is invalid.

• ERR_LIVENESS_FAILED: The user's face image in face_base_64 is determined to not be live and require_live_face was set to true during hash creation.

• ERR_VERIFICATION_FAILED: Decryption failed due to the face_base_64 not matching the face used to create the hash.

Additional Liveness Error Codes:

If the face_base_64 is determined to be not suitable for liveness, the following error codes may be returned:

• ERR_LIVENESS_FACE_ANGLE_TOO_LARGE: The face angle is too large (the user is not facing the camera).

• ERR_LIVENESS_FACE_IS_OCCLUDED: The face is occluded (e.g., by a mask).

• ERR_LIVENESS_FACE_CLOSE_TO_BORDER: The face is too close to the border of the image.

• ERR_LIVENESS_FACE_TOO_SMALL: The face is too small in the image.

• ERR_LIVENESS_EYES_CLOSED: The eyes are closed in the image.