EVP_VerifyInit_ex, EVP_VerifyInit, EVP_VerifyUpdate, EVP_VerifyFinal - EVP
signature verification functions
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);
The EVP signature verification routines are a high level interface to digital
sets up verification context ctx
to use digest
from ENGINE impl
must be created by calling
before calling this function.
bytes of data at d
verification context ctx
. This function can be called several times on
the same ctx
to include additional data.
verifies the data in ctx
using the public key
and against the siglen
bytes at sigbuf
initializes verification context ctx
to use the
default implementation of digest type
return 1 for success
and 0 for failure.
returns 1 for a correct signature, 0 for failure and -1
if some other error occurred.
The error codes can be obtained by ERR_get_error(3)
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.
Due to the link between message digests and public key algorithms the correct
digest algorithm must be used with the correct public key type. A list of
algorithms and associated public key algorithms appears in
The call to EVP_VerifyFinal()
internally finalizes a copy of the digest
context. This means that calls to EVP_VerifyUpdate()
can be called later to digest and verify additional
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
Older versions of this documentation wrongly stated that calls to
could not be made after calling
Since the public key is passed in the call to EVP_SignFinal()
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_VerifyDigest*() function.
Copyright 2000-2017 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