EVP_SIGNATURE-LMS7ssl
The evp_pkey lms signature implementation
Overview
The LMS EVP_PKEY implementation supports Leighton-Micali Signatures (LMS) described in [RFC 8554](https://datatracker.ietf.org/doc/html/rfc8854) and [SP 800-208](https://csrc.nist.gov/pubs/sp/800/208/final). The OpenSSL providers only support LMS signature verification, as this is a [SP 800-208](https://csrc.nist.gov/pubs/sp/800/208/final) requirement for FIPS software modules.
EVP_PKEY_verify_message_init() and EVP_PKEY_verify() are the only supported functions used for LMS signatures. Streaming is not currently supported, and since the signature data contains data related to the digest used, functions that specify the digest name are not necessary.
FIPS indicator
The following parameter can be retrieved using EVP_PKEY_CTX_get_params(3):
- "fips-indicator" (
OSSL_SIGNATURE_PARAM_FIPS_APPROVED_INDICATOR) <integer> -
The OpenSSL FIPS provider returns 1 if the operation is FIPS approved, or 0 otherwise. See "FIPS indicators" in fips_module(7) for more information.
Notes
LMS support is disabled by default at compile-time. To enable, specify the enable-lms build configuration option.
LMS should only be used for older deployments. New deployments should use either EVP_SIGNATURE-ML-DSA(7) or <L/EVP_SIGNATURE-SLH-DSA(7)>.
Examples
Error checking has been omitted from the following examples
LMS signature verification
/* See L<EVP_PKEY-LMS(7)/EXAMPLES for an example of loading a LMS |pub| key */ctx = EVP_PKEY_CTX_new_from_pkey(libctx, pub, propq);sig = EVP_SIGNATURE_fetch(libctx, "LMS", propq);EVP_PKEY_verify_message_init(ctx, sig, NULL);/** EVP_PKEY_verify_message_update() and EVP_PKEY_verify_message_final()* are not supported*/ret = EVP_PKEY_verify(ctx, sigdata, sigdata_len, msg, msglen);/** ret == 1 indicates success, 0 verify failure and < 0 for some* other error.*/