openssl/doc/crypto/EVP_PKEY_sign.pod
Dr. Stephen Henson 64cee65ebc New docs.
2006-07-08 11:13:01 +00:00

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=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
After the call to EVP_PKEY_sign_init() algorithm specific control
operations can be performed to set any appropriate parameters for the
operation.
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 PKCS#1 and SHA256 digest:
[to be added]
=head1 SEE ALSO
L<EVP_PKEY_CTX_new(3)|EVP_PKEY_CTX_new(3)>,
L<EVP_PKEY_encrypt(3)|EVP_PKEY_encrypt(3)>,
L<EVP_PKEY_decrypt(3)|EVP_PKEY_decrypt(3)>,
L<EVP_PKEY_verify(3)|EVP_PKEY_verify(3)>,
L<EVP_PKEY_verifyrecover(3)|EVP_PKEY_verifyrecover(3)>,
L<EVP_PKEY_derive(3)|EVP_PKEY_derive(3)>
=head1 HISTORY
These functions were first added to OpenSSL 0.9.9.
=cut