96 lines
3.1 KiB
Plaintext
96 lines
3.1 KiB
Plaintext
|
=pod
|
||
|
|
|
||
|
|
=head1 NAME
|
||
|
|
|
||
|
|
EVP_VerifyInit_ex,
|
||
|
|
EVP_VerifyInit, EVP_VerifyUpdate, EVP_VerifyFinal
|
||
|
|
- EVP signature verification functions
|
||
|
|
|
||
|
|
=head1 SYNOPSIS
|
||
|
|
|
||
|
|
#include <openssl/evp.h>
|
||
|
|
|
||
|
|
int EVP_VerifyInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl);
|
||
|
|
int EVP_VerifyUpdate(EVP_MD_CTX *ctx, const void *d, unsigned int cnt);
|
||
|
|
int EVP_VerifyFinal(EVP_MD_CTX *ctx, unsigned char *sigbuf, unsigned int siglen,
|
||
|
|
EVP_PKEY *pkey);
|
||
|
|
|
||
|
|
int EVP_VerifyInit(EVP_MD_CTX *ctx, const EVP_MD *type);
|
||
|
|
|
||
|
|
=head1 DESCRIPTION
|
||
|
|
|
||
|
|
The EVP signature verification routines are a high-level interface to digital
|
||
|
|
signatures.
|
||
|
|
|
||
|
|
EVP_VerifyInit_ex() sets up verification context B<ctx> to use digest
|
||
|
|
B<type> from ENGINE B<impl>. B<ctx> must be created by calling
|
||
|
|
EVP_MD_CTX_new() before calling this function.
|
||
|
|
|
||
|
|
EVP_VerifyUpdate() hashes B<cnt> bytes of data at B<d> into the
|
||
|
|
verification context B<ctx>. This function can be called several times on the
|
||
|
|
same B<ctx> to include additional data.
|
||
|
|
|
||
|
|
EVP_VerifyFinal() verifies the data in B<ctx> using the public key B<pkey>
|
||
|
|
and against the B<siglen> bytes at B<sigbuf>.
|
||
|
|
|
||
|
|
EVP_VerifyInit() initializes verification context B<ctx> to use the default
|
||
|
|
implementation of digest B<type>.
|
||
|
|
|
||
|
|
=head1 RETURN VALUES
|
||
|
|
|
||
|
|
EVP_VerifyInit_ex() and EVP_VerifyUpdate() return 1 for success and 0 for
|
||
|
|
failure.
|
||
|
|
|
||
|
|
EVP_VerifyFinal() returns 1 for a correct signature, 0 for failure and -1 if some
|
||
|
|
other error occurred.
|
||
|
|
|
||
|
|
The error codes can be obtained by L<ERR_get_error(3)>.
|
||
|
|
|
||
|
|
=head1 NOTES
|
||
|
|
|
||
|
|
The B<EVP> interface to digital signatures should almost always be used in
|
||
|
|
preference to the low-level interfaces. This is because the code then becomes
|
||
|
|
transparent to the algorithm used and much more flexible.
|
||
|
|
|
||
|
|
The call to EVP_VerifyFinal() internally finalizes a copy of the digest context.
|
||
|
|
This means that calls to EVP_VerifyUpdate() and EVP_VerifyFinal() can be called
|
||
|
|
later to digest and verify additional data.
|
||
|
|
|
||
|
|
Since only a copy of the digest context is ever finalized the context must
|
||
|
|
be cleaned up after use by calling EVP_MD_CTX_free() or a memory leak
|
||
|
|
will occur.
|
||
|
|
|
||
|
|
=head1 BUGS
|
||
|
|
|
||
|
|
Older versions of this documentation wrongly stated that calls to
|
||
|
|
EVP_VerifyUpdate() could not be made after calling EVP_VerifyFinal().
|
||
|
|
|
||
|
|
Since the public key is passed in the call to EVP_SignFinal() any error
|
||
|
|
relating to the private key (for example an unsuitable key and digest
|
||
|
|
combination) will not be indicated until after potentially large amounts of
|
||
|
|
data have been passed through EVP_SignUpdate().
|
||
|
|
|
||
|
|
It is not possible to change the signing parameters using these function.
|
||
|
|
|
||
|
|
The previous two bugs are fixed in the newer EVP_DigestVerify*() function.
|
||
|
|
|
||
|
|
=head1 SEE ALSO
|
||
|
|
|
||
|
|
L<evp(7)>,
|
||
|
|
L<EVP_SignInit(3)>,
|
||
|
|
L<EVP_DigestInit(3)>,
|
||
|
|
L<evp(7)>, L<HMAC(3)>, L<MD2(3)>,
|
||
|
|
L<MD5(3)>, L<MDC2(3)>, L<RIPEMD160(3)>,
|
||
|
|
L<SHA1(3)>, L<dgst(1)>
|
||
|
|
|
||
|
|
=head1 COPYRIGHT
|
||
|
|
|
||
|
|
Copyright 2000-2020 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
|