=head1 NAME
-EVP_DigestVerifyInit, EVP_DigestVerifyUpdate, EVP_DigestVerifyFinal - EVP signature verification functions
+EVP_DigestVerifyInit, EVP_DigestVerifyUpdate, EVP_DigestVerifyFinal,
+EVP_DigestVerify - EVP signature verification functions
=head1 SYNOPSIS
#include <openssl/evp.h>
int EVP_DigestVerifyInit(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx,
- const EVP_MD *type, ENGINE *e, EVP_PKEY *pkey);
+ const EVP_MD *type, ENGINE *e, EVP_PKEY *pkey);
int EVP_DigestVerifyUpdate(EVP_MD_CTX *ctx, const void *d, size_t cnt);
- int EVP_DigestVerifyFinal(EVP_MD_CTX *ctx, const unsigned char *sig, size_t siglen);
+ int EVP_DigestVerifyFinal(EVP_MD_CTX *ctx, const unsigned char *sig,
+ size_t siglen);
+ int EVP_DigestVerify(EVP_MD_CTX *ctx, const unsigned char *sigret,
+ size_t siglen, const unsigned char *tbs, size_t tbslen);
=head1 DESCRIPTION
The EVP signature routines are a high level interface to digital signatures.
EVP_DigestVerifyInit() sets up verification context B<ctx> to use digest
-B<type> from ENGINE B<
impl> and public key B<pkey>. B<ctx> must be created
-with EVP_MD_CTX_new() before calling this function. If B<pctx> is not NULL the
+B<type> from ENGINE B<
e> and public key B<pkey>. B<ctx> must be created
+with EVP_MD_CTX_new() before calling this function. If B<pctx> is not NULL, the
EVP_PKEY_CTX of the verification operation will be written to B<*pctx>: this
-can be used to set alternative verification options.
+can be used to set alternative verification options. Note that any existing
+value in B<*pctx> is overwritten. The EVP_PKEY_CTX value returned must not be freed
+directly by the application if B<ctx> is not assigned an EVP_PKEY_CTX value before
+being passed to EVP_DigestVerifyInit() (which means the EVP_PKEY_CTX is created
+inside EVP_DigestVerifyInit() and it will be freed automatically when the
+EVP_MD_CTX is freed).
+
+No B<EVP_PKEY_CTX> will be created by EVP_DigestSignInit() if the passed B<ctx>
+has already been assigned one via L<EVP_MD_CTX_set_ctx(3)>. See also L<SM2(7)>.
EVP_DigestVerifyUpdate() hashes B<cnt> bytes of data at B<d> into the
verification context B<ctx>. This function can be called several times on the
EVP_DigestVerifyFinal() verifies the data in B<ctx> against the signature in
B<sig> of length B<siglen>.
+EVP_DigestVerify() verifies B<tbslen> bytes at B<tbs> against the signature
+in B<sig> of length B<siglen>.
+
=head1 RETURN VALUES
EVP_DigestVerifyInit() and EVP_DigestVerifyUpdate() return 1 for success and 0
for failure.
-EVP_DigestVerifyFinal() returns 1 for success; any other value indicates
-failure. A return value of zero indicates that the signature did not verify
-successfully (that is, tbs did not match the original data or the signature had
-an invalid form), while other values indicate a more serious error (and
-sometimes also indicate an invalid signature form).
+EVP_DigestVerifyFinal() and EVP_DigestVerify() return 1 for success; any other
+value indicates failure. A return value of zero indicates that the signature
+did not verify successfully (that is, B<tbs> did not match the original data or
+the signature had an invalid form), while other values indicate a more serious
+error (and sometimes also indicate an invalid signature form).
The error codes can be obtained from L<ERR_get_error(3)>.
preference to the low level interfaces. This is because the code then becomes
transparent to the algorithm used and much more flexible.
+EVP_DigestVerify() is a one shot operation which verifies a single block of
+data in one function. For algorithms that support streaming it is equivalent
+to calling EVP_DigestVerifyUpdate() and EVP_DigestVerifyFinal(). For
+algorithms which do not support streaming (e.g. PureEdDSA) it is the only way
+to verify data.
+
In previous versions of OpenSSL there was a link between message digest types
and public key algorithms. This meant that "clone" digests such as EVP_dss1()
needed to be used to sign using SHA1 and DSA. This is no longer necessary and
the use of clone digest is now discouraged.
-For some key types and parameters the random number generator must be seeded
-or the operation will fail.
+For some key types and parameters the random number generator must be seeded.
+If the automatic seeding or reseeding of the OpenSSL CSPRNG fails due to
+external circumstances (see L<RAND(7)>), the operation will fail.
The call to EVP_DigestVerifyFinal() internally finalizes a copy of the digest
context. This means that 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_cleanup() or a memory leak
+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 SEE ALSO
L<EVP_DigestSignInit(3)>,
-L<EVP_DigestInit(3)>, L<err(7)>,
+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)>
+L<SHA1(3)>, L<dgst(1)>,
+L<RAND(7)>
=head1 HISTORY
EVP_DigestVerifyInit(), EVP_DigestVerifyUpdate() and EVP_DigestVerifyFinal()
-were first added to OpenSSL 1.0.0.
+were added in OpenSSL 1.0.0.
=head1 COPYRIGHT
-Copyright 2006-2016 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2006-2018 The OpenSSL Project Authors. All Rights Reserved.
-Licensed under the OpenSSL license (the "License"). You may not use
+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>.
projects / openssl.git / blobdiff