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EVP_SIGNATURE-DSA(7)                OpenSSL               EVP_SIGNATURE-DSA(7)


NAME
       EVP_SIGNATURE-DSA - The EVP_PKEY DSA signature implementation

DESCRIPTION
       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.  See EVP_PKEY-DSA(7) for information related to
       DSA keys.

       As part of FIPS 140-3 DSA is not longer FIPS approved for key
       generation and signature validation, but is still allowed for signature
       verification.

   Algorithm Names
       In this list, names are grouped together to signify that they are the
       same algorithm having multiple names.  This also includes the OID in
       canonical decimal form (which means that they are possible to fetch if
       the caller has a mere OID which came out in this form after a call to
       OBJ_obj2txt(3)).

       "DSA", "dsaEncryption", "1.2.840.10040.4.1"
           The base signature algorithm, supported explicitly fetched with
           EVP_PKEY_sign_init_ex2(3), and implicitly fetched (through EC keys)
           with EVP_DigestSignInit(3) and EVP_DigestVerifyInit(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).

   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().

       "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
       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.

COPYRIGHT
       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>.

3.5.1                             2025-07-01              EVP_SIGNATURE-DSA(7)