EVP_SIGNATURE-DSA(7ossl)

📦 version 3.5.0, in opensuse-leap 16.0

💅 EVP_SIGNATURE-DSA 💅

okay bestie so this is the EVP_SIGNATURE-DSA page from the 7ossl manual set — it's literally the whole guide to the EVP_PKEY DSA signature implementation and we're gonna get through it together 🫶

✨ NAME ✨

EVP_SIGNATURE-DSA — The EVP_PKEY DSA signature implementation. that's it, that's the whole name, and honestly she ate 💅

🌸 DESCRIPTION 🌸

So, support for computing DSA signatures ✨ The signature produced with EVP_PKEY_sign(3) is DER encoded ASN.1 in the form described in RFC 3279, section 2.2.2. and if you need the tea on DSA keys themselves, go check EVP_PKEY-DSA(7) 💖

🚨 FIPS alert bestie 🚨 As part of FIPS 140-3, DSA is no longer FIPS approved for key generation and signature validation — but it's still allowed for signature verification. the way that's such a specific vibe and honestly kinda iconic for how confusing it is 😭

🎀 Algorithm Names 🎀

okay so in this list, names are grouped together to signify that they're the same algorithm having multiple names. that also includes the OID in canonical decimal form (which means you can totally fetch them if the caller only has a mere OID that came out in this form after a call to OBJ_obj2txt(3)) 🔥

It can't be used with EVP_PKEY_sign_message_init(3) 🙈

  • "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"

✨ 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(). This may be called 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(). timing is everything bestie ⏰

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

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

  • "nonce-type" (OSSL_SIGNATURE_PARAM_NONCE_TYPE) <unsigned integer>
  • "key-check" (OSSL_SIGNATURE_PARAM_FIPS_KEY_CHECK) <integer>
  • "digest-check" (OSSL_SIGNATURE_PARAM_FIPS_DIGEST_CHECK) <integer>
  • "sign-check" (OSSL_SIGNATURE_PARAM_FIPS_SIGN_CHECK) <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) <octet string>
  • "digest" (OSSL_SIGNATURE_PARAM_DIGEST) <UTF8 string>
  • "nonce-type" (OSSL_SIGNATURE_PARAM_NONCE_TYPE) <unsigned integer>
  • "fips-indicator" (OSSL_SIGNATURE_PARAM_FIPS_APPROVED_INDICATOR) <integer>

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

👀 SEE ALSO 👀

go give these a lil read, iykyk:

EVP_PKEY_CTX_set_params(3), EVP_PKEY_sign(3), EVP_PKEY_verify(3), provider-signature(7)

🕰️ 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. the timeline lore is real fr fr

Copyright 2020-2024 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>. 🫶

and that's the whole page bestie, no cap 💖 this was EVP_SIGNATURE-DSA(7ossl), version 3.5.0, dated 2026-09-25 — mwah, go sign something, periodt 🌈✨🎀

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