# SignatureAlgorithm

The algorithm that the client should use / has used to sign data using its private key for proof-of-posession.

| Enums ||
|---|---|
| `SIGNATURE_ALGORITHM_UNSPECIFIED` | Default value. This value is unused. |
| `SIGNATURE_ALGORITHM_RSA_PKCS1_V1_5_SHA256` | The server-side builds the PKCS#1 DigestInfo and sends a SHA256 hash of it to the client. The client should sign using RSA with PKCS#1 v1.5 padding. |
| `SIGNATURE_ALGORITHM_ECDSA_SHA256` | The server-side builds the PKCS#1 DigestInfo and sends it unhashed to the client. The client is responsible for signing and hashing using the P-256 curve. |