=pod

=head1 NAME

EVP_SIGNATURE-ECDSA - The EVP_PKEY B<ECDSA> signature implementation

=head1 DESCRIPTION

Support for computing ECDSA signatures.
See L<EVP_PKEY-EC(7)> for information related to EC keys.

=head2 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 L<OBJ_obj2txt(3)>).

=over 4

=item "ECDSA"

The base signature algorithm, supported explicitly fetched with
L<EVP_PKEY_sign_init_ex2(3)>, and implicitly fetched (through
L<EC keys|EVP_PKEY-EC(7)>) with L<EVP_DigestSignInit(3)> and
L<EVP_DigestVerifyInit(3)>.

It can't be used with L<EVP_PKEY_sign_message_init(3)>

=item "ECDSA-SHA1", "ECDSA-SHA-1", "ecdsa-with-SHA1", "1.2.840.10045.4.1"

=item "ECDSA-SHA2-224", "ECDSA-SHA224", "ecdsa-with-SHA224", "1.2.840.10045.4.3.1"

=item "ECDSA-SHA2-256", "ECDSA-SHA256", "ecdsa-with-SHA256", "1.2.840.10045.4.3.2"

=item "ECDSA-SHA2-384", "ECDSA-SHA384", "ecdsa-with-SHA384", "1.2.840.10045.4.3.3"

=item "ECDSA-SHA2-512", "ECDSA-SHA512", "ecdsa-with-SHA512", "1.2.840.10045.4.3.4"

=item "ECDSA-SHA3-224", "ecdsa_with_SHA3-224", "id-ecdsa-with-sha3-224", "2.16.840.1.101.3.4.3.9"

=item "ECDSA-SHA3-256", "ecdsa_with_SHA3-256", "id-ecdsa-with-sha3-256", "2.16.840.1.101.3.4.3.10"

=item "ECDSA-SHA3-384", "ecdsa_with_SHA3-384", "id-ecdsa-with-sha3-384", "2.16.840.1.101.3.4.3.11"

=item "ECDSA-SHA3-512", "ecdsa_with_SHA3-512", "id-ecdsa-with-sha3-512", "2.16.840.1.101.3.4.3.12"

ECDSA signature schemes with diverse message digest algorithms.  They are all
supported explicitly fetched with L<EVP_PKEY_sign_init_ex2(3)> and
L<EVP_PKEY_sign_message_init(3)>.

=back

=head2 ECDSA 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().

=over 4

=item "digest" (B<OSSL_SIGNATURE_PARAM_DIGEST>) <UTF8 string>

=item "properties" (B<OSSL_SIGNATURE_PARAM_PROPERTIES>) <UTF8 string>

These two are not supported with the ECDSA signature schemes that already
include a message digest algorithm, See L</Algorithm Names> above.

=item "nonce-type" (B<OSSL_SIGNATURE_PARAM_NONCE_TYPE>) <unsigned integer>

=item "key-check" (B<OSSL_SIGNATURE_PARAM_FIPS_KEY_CHECK>) <integer>

=item "digest-check" (B<OSSL_SIGNATURE_PARAM_FIPS_DIGEST_CHECK>) <integer>

These parameters are described in L<provider-signature(7)>.

=back

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

=over 4

=item "algorithm-id" (B<OSSL_SIGNATURE_PARAM_ALGORITHM_ID>) <octet string>

=item "digest" (B<OSSL_SIGNATURE_PARAM_DIGEST>) <UTF8 string>

=item "nonce-type" (B<OSSL_SIGNATURE_PARAM_NONCE_TYPE>) <unsigned integer>

=item "fips-indicator" (B<OSSL_SIGNATURE_PARAM_FIPS_APPROVED_INDICATOR>) <integer>

=item "verify-message" (B<OSSL_SIGNATURE_PARAM_FIPS_VERIFY_MESSAGE> <integer>

The parameters are described in L<provider-signature(7)>.

=back

=head1 SEE ALSO

L<EVP_PKEY_CTX_set_params(3)>,
L<EVP_PKEY_sign(3)>,
L<EVP_PKEY_verify(3)>,
L<provider-signature(7)>,

=head1 COPYRIGHT

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
L<https://www.openssl.org/source/license.html>.

=cut
