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Diffstat (limited to 'crypto/openssl/doc/man3/EVP_PKEY_sign.pod')
-rw-r--r-- | crypto/openssl/doc/man3/EVP_PKEY_sign.pod | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/crypto/openssl/doc/man3/EVP_PKEY_sign.pod b/crypto/openssl/doc/man3/EVP_PKEY_sign.pod new file mode 100644 index 000000000000..1672831ff015 --- /dev/null +++ b/crypto/openssl/doc/man3/EVP_PKEY_sign.pod @@ -0,0 +1,115 @@ +=pod + +=head1 NAME + +EVP_PKEY_sign_init, EVP_PKEY_sign - sign using a public key algorithm + +=head1 SYNOPSIS + + #include <openssl/evp.h> + + int EVP_PKEY_sign_init(EVP_PKEY_CTX *ctx); + int EVP_PKEY_sign(EVP_PKEY_CTX *ctx, + unsigned char *sig, size_t *siglen, + const unsigned char *tbs, size_t tbslen); + +=head1 DESCRIPTION + +The EVP_PKEY_sign_init() function initializes a public key algorithm +context using key B<pkey> for a signing operation. + +The EVP_PKEY_sign() function performs a public key signing operation +using B<ctx>. The data to be signed is specified using the B<tbs> and +B<tbslen> parameters. If B<sig> is B<NULL> then the maximum size of the output +buffer is written to the B<siglen> parameter. If B<sig> is not B<NULL> then +before the call the B<siglen> parameter should contain the length of the +B<sig> buffer, if the call is successful the signature is written to +B<sig> and the amount of data written to B<siglen>. + +=head1 NOTES + +EVP_PKEY_sign() does not hash the data to be signed, and therefore is +normally used to sign digests. For signing arbitrary messages, see the +L<EVP_DigestSignInit(3)> and +L<EVP_SignInit(3)> signing interfaces instead. + +After the call to EVP_PKEY_sign_init() algorithm specific control +operations can be performed to set any appropriate parameters for the +operation (see L<EVP_PKEY_CTX_ctrl(3)>). + +The function EVP_PKEY_sign() can be called more than once on the same +context if several operations are performed using the same parameters. + +=head1 RETURN VALUES + +EVP_PKEY_sign_init() and EVP_PKEY_sign() return 1 for success and 0 +or a negative value for failure. In particular a return value of -2 +indicates the operation is not supported by the public key algorithm. + +=head1 EXAMPLE + +Sign data using RSA with PKCS#1 padding and SHA256 digest: + + #include <openssl/evp.h> + #include <openssl/rsa.h> + + EVP_PKEY_CTX *ctx; + /* md is a SHA-256 digest in this example. */ + unsigned char *md, *sig; + size_t mdlen = 32, siglen; + EVP_PKEY *signing_key; + + /* + * NB: assumes signing_key and md are set up before the next + * step. signing_key must be an RSA private key and md must + * point to the SHA-256 digest to be signed. + */ + ctx = EVP_PKEY_CTX_new(signing_key, NULL /* no engine */); + if (!ctx) + /* Error occurred */ + if (EVP_PKEY_sign_init(ctx) <= 0) + /* Error */ + if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PADDING) <= 0) + /* Error */ + if (EVP_PKEY_CTX_set_signature_md(ctx, EVP_sha256()) <= 0) + /* Error */ + + /* Determine buffer length */ + if (EVP_PKEY_sign(ctx, NULL, &siglen, md, mdlen) <= 0) + /* Error */ + + sig = OPENSSL_malloc(siglen); + + if (!sig) + /* malloc failure */ + + if (EVP_PKEY_sign(ctx, sig, &siglen, md, mdlen) <= 0) + /* Error */ + + /* Signature is siglen bytes written to buffer sig */ + + +=head1 SEE ALSO + +L<EVP_PKEY_CTX_new(3)>, +L<EVP_PKEY_CTX_ctrl(3)>, +L<EVP_PKEY_encrypt(3)>, +L<EVP_PKEY_decrypt(3)>, +L<EVP_PKEY_verify(3)>, +L<EVP_PKEY_verify_recover(3)>, +L<EVP_PKEY_derive(3)> + +=head1 HISTORY + +These functions were added in OpenSSL 1.0.0. + +=head1 COPYRIGHT + +Copyright 2006-2016 The OpenSSL Project Authors. All Rights Reserved. + +Licensed under the OpenSSL license (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 |