EVP_SIGNATURE-DSA(7ossl)

📦
version 3.5.9 · 8 versions
, in alpine 3.23, alpine 3.24

💖 NAME 💖

okay bestie, welcome to the OpenSSL EVP_SIGNATURE-DSA(7ossl) page — it's the manual for the EVP_PKEY DSA signature implementation. No cap, that's literally the whole NAME moment: EVP_SIGNATURE-DSA — The EVP_PKEY DSA signature implementation.

✨ DESCRIPTION ✨

So this is all about computing DSA signatures. The signature you get from EVP_PKEY_sign(3) is DER-encoded ASN.1, in the form described in RFC 3279, section 2.2.2. If you need the tea on DSA keys themselves, go see EVP_PKEY-DSA(7).

Important FIPS 140-3 note, bestie: DSA is no longer FIPS approved for key generation and signature validation, but it's still allowed for signature verification. Keep that vibe in mind — periodt. 🫶

🔥 Algorithm Names 🔥

okay so in this list, names are grouped together when they mean the same algorithm with multiple names. The OID is included in canonical decimal form too — that means they're possible to fetch if the caller has a mere OID that came out in this form after a call to OBJ_obj2txt(3). iykyk.

Then the digest-bundled besties, all grouped by their alias sets:

  • "DSA-SHA1", "DSA-SHA-1", "dsaWithSHA1", "1.2.840.10040.4.3"
  • "DSA-SHA2-224", "DSA-SHA224", "dsa_with_SHA224", "2.16.840.1.101.3.4.3.1"
  • "DSA-SHA2-256", "DSA-SHA256", "dsa_with_SHA256", "2.16.840.1.101.3.4.3.2"
  • "DSA-SHA2-384", "DSA-SHA384", "dsa_with_SHA384", "id-dsa-with-sha384", "1.2.840.1.101.3.4.3.3"
  • "DSA-SHA2-512", "DSA-SHA512", "dsa_with_SHA512", "id-dsa-with-sha512", "1.2.840.1.101.3.4.3.4"
  • "DSA-SHA3-224", "dsa_with_SHA3-224", "id-dsa-with-sha3-224", "2.16.840.1.101.3.4.3.5"
  • "DSA-SHA3-256", "dsa_with_SHA3-256", "id-dsa-with-sha3-256", "2.16.840.1.101.3.4.3.6"
  • "DSA-SHA3-384", "dsa_with_SHA3-384", "id-dsa-with-sha3-384", "2.16.840.1.101.3.4.3.7"
  • "DSA-SHA3-512", "dsa_with_SHA3-512", "id-dsa-with-sha3-512", "2.16.840.1.101.3.4.3.8"

These are DSA signature schemes with diverse message digest algorithms. They are all supported explicitly fetched with EVP_PKEY_sign_init_ex2(3) and EVP_PKEY_sign_message_init(3). slay. 💅

💜 Signature Parameters 💜

The following signature parameters can be set using EVP_PKEY_CTX_set_params(). You can call that after EVP_PKEY_sign_init() or EVP_PKEY_verify_init(), and before calling EVP_PKEY_sign() or EVP_PKEY_verify(). They may also be set using EVP_PKEY_sign_init_ex() or EVP_PKEY_verify_init_ex().

Settable crew:

  • "digest" (OSSL_SIGNATURE_PARAM_DIGEST) — type <UTF8 string>
  • "properties" (OSSL_SIGNATURE_PARAM_PROPERTIES) — type <UTF8 string>

These two are not supported with the DSA signature schemes that already include a message digest algorithm — see Algorithm Names above, bestie.

  • "nonce-type" (OSSL_SIGNATURE_PARAM_NONCE_TYPE) — type <unsigned integer>
  • "key-check" (OSSL_SIGNATURE_PARAM_FIPS_KEY_CHECK) — type <integer>
  • "digest-check" (OSSL_SIGNATURE_PARAM_FIPS_DIGEST_CHECK) — type <integer>
  • "sign-check" (OSSL_SIGNATURE_PARAM_FIPS_SIGN_CHECK) — type <int>

The settable parameters are described in provider-signature(7).

The following signature parameters can be retrieved using EVP_PKEY_CTX_get_params().

  • "algorithm-id" (OSSL_SIGNATURE_PARAM_ALGORITHM_ID) — type <octet string>
  • "digest" (OSSL_SIGNATURE_PARAM_DIGEST) — type <UTF8 string>
  • "nonce-type" (OSSL_SIGNATURE_PARAM_NONCE_TYPE) — type <unsigned integer>
  • "fips-indicator" (OSSL_SIGNATURE_PARAM_FIPS_APPROVED_INDICATOR) — type <integer>

The gettable parameters are described in provider-signature(7).

🦋 SEE ALSO 🦋

okay go peek at EVP_PKEY_CTX_set_params(3), EVP_PKEY_sign(3), EVP_PKEY_verify(3), and provider-signature(7), bestie.

🌸 HISTORY 🌸

DSA Key generation and signature generation are no longer FIPS approved in OpenSSL 3.4. See "FIPS indicators" in fips_module(7) for more information.

Copyright 2020-2026 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>.

okay that's the whole page — version 3.5.9, dated 2026-09-29, manual EVP_SIGNATURE-DSA(7ossl). mwah 💋

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