ECDSA

Important

Only DER-encoded keys are supported for the C harness.

Test signing

To test a function that signs with ECDSA, its name must conform to the following convention:

CC_ECDSA_sign_<curve>_<hash function>_DER_[prehashed]

Where:

  • curve is one of: P-224, P-256, P-384, P-521, B-283, B-409, B-571.

  • hash function is one of: SHA-256, SHA-384, SHA-512.

int ECDSA_sign(
uint8_t *sig,
size_t sig_size,
const uint8_t *sk,
size_t sk_size,
const uint8_t *msg,
size_t msg_size,
)

Signs a message with ECDSA.

Parameters:

  • sig – [Out] An allocated buffer for returning the signature in DER format.

  • sig_size – [In] The size of the sig buffer.

  • sk – [In] The secret key to use for signing, in DER format.

  • sk_len – [In] The size of the secret key in bytes.

  • msg – [In] The message to sign.

  • msg_size – [In] The size of the message in bytes.

Returns:

A status value.

Return values:

  • 1 – OK.

  • -1 – An error occurred.

Verify

To test a function that verifies ECDSA signatures, its name must conform to the following convention:

CC_ECDSA_verify_<curve>_<hash function>_[prehashed]

  • curve is one of: P-224, P-256, P-384, P-521, B-283, B-409, B-571.

  • hash function is one of: SHA-256, SHA-384, SHA-512.

Additionally, the following combinations of curve and hash function are available when using resilience test vectors:

  • P-224, SHA3-256.

  • P-224, SHA3-256.

  • P-256, SHA3-256.

  • P-256, SHA3-512.

  • P-384, SHA3-384.

  • P-384, SHA3-512.

  • P-521, SHA3-512.

int ECDSA_verify(
const uint8_t *pk,
const size_t pk_size,
const uint8_t *msg,
const size_t msg_size,
const uint8_t *sig,
const size_t sig_size,
)

Verifies an ECDSA signature.

Parameters:

  • pk – [In] The public key to use for verifying the signature.

  • pk_size – [In] The size of pk in bytes.

  • msg – [In] The message.

  • msg_size – [In] The size of msg in bytes.

  • sig – [In] The signature to verify.

  • sig_size – [In] The size of sig in bytes.

Returns:

A status value.

Return values:

  • 1 – OK.

  • 0 – The signature is invalid.

  • -1 – An error occurred.