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_DogestVerify() verifies B<tbslen> bytes at B<tbs> against the signature
+EVP_DigestVerify() verifies B<tbslen> bytes at B<tbs> against the signature
in B<sig> of length B<siglen>.
=head1 RETURN VALUES
preference to the low level interfaces. This is because the code then becomes
transparent to the algorithm used and much more flexible.
-EVP_DigesVerify() is a one shot operation which verifies a single block of
+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
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_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 2006-2017 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