---
name: "EVP_SIGNATURE-LMS"
section: "7ssl"
platform: "linux"
package: "openssl"
version: "3.6.5-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/EVP_SIGNATURE-LMS"
---

# EVP\_SIGNATURE-LMS(7ssl)

The EVP\_PKEY LMS signature implementation

## NAME

EVP\_SIGNATURE-LMS - The EVP\_PKEY LMS signature implementation

## DESCRIPTION

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.
  */
```

## SEE ALSO

**EVP\_PKEY-LMS**(7), **provider-signature**(7),

## HISTORY

This functionality was added in OpenSSL 3.6.

## COPYRIGHT

Copyright 2025-2026 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License").  You may not use this file except in compliance with the License.  You can obtain a copy in the file LICENSE in the source distribution or at \<https://www.openssl.org/source/license.html\>.