New docs.

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Dr. Stephen Henson 2006-07-08 11:13:01 +00:00
parent ba544377fb
commit 64cee65ebc
2 changed files with 72 additions and 1 deletions

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=head1 NAME
EVP_PKEY_encrypt_init, EVP_PKEY_encrypt - encrypt using a public key algorithm
EVP_PKEY_sign_init, EVP_PKEY_sign - sign using a public key algorithm
=head1 SYNOPSIS

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=pod
=head1 NAME
EVP_PKEY_verifyrecover_init, EVP_PKEY_verifyrecover - recover signature using a public key algorithm
=head1 SYNOPSIS
#include <openssl/evp.h>
int EVP_PKEY_verifyrecover_init(EVP_PKEY_CTX *ctx);
int EVP_PKEY_verifyrecover(EVP_PKEY_CTX *ctx,
unsigned char *rout, size_t *routlen,
const unsigned char *sig, size_t siglen);
=head1 DESCRIPTION
The EVP_PKEY_verifyrecover_init() function initializes a public key algorithm
context using key B<pkey> for a verify recover operation.
The EVP_PKEY_verifyrecover() function recovers signed data
using B<ctx>. The signature is specified using the B<sig> and
B<siglen> parameters. If B<rout> is B<NULL> then the maximum size of the output
buffer is written to the B<routlen> parameter. If B<rout> is not B<NULL> then
before the call the B<routlen> parameter should contain the length of the
B<rout> buffer, if the call is successful recovered data is written to
B<rout> and the amount of data written to B<routlen>.
=head1 NOTES
Normally an application is only interested in whether a signature verification
operation is successful in those cases the EVP_verify() function should be
used.
Sometimes however it is useful to obtain the data originally signed using a
signing operation. Only certain public key algorithms can recover a signature
in this way (for example RSA in PKCS padding mode).
After the call to EVP_PKEY_verifyrecover_init() algorithm specific control
operations can be performed to set any appropriate parameters for the
operation.
The function EVP_PKEY_verifyrecover() can be called more than once on the same
context if several operations are performed using the same parameters.
=head1 RETURN VALUES
EVP_PKEY_verifyrecover_init() and EVP_PKEY_verifyrecover() 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
Recover digest originally signed 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_sign(3)|EVP_PKEY_sign(3)>,
L<EVP_PKEY_verify(3)|EVP_PKEY_verify(3)>,
L<EVP_PKEY_derive(3)|EVP_PKEY_derive(3)>
=head1 HISTORY
These functions were first added to OpenSSL 0.9.9.
=cut