Sortix 1.1dev nightly manual
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EVP_VERIFYINIT(3) | Library Functions Manual | EVP_VERIFYINIT(3) |
NAME
EVP_VerifyInit_ex
,
EVP_VerifyUpdate
,
EVP_VerifyFinal
,
EVP_VerifyInit
—
EVP signature verification functions
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);
DESCRIPTION
The EVP signature verification routines are a high level interface to digital signatures.EVP_VerifyInit_ex
() sets up a verification
context ctx to use the digest
type from
ENGINE impl.
ctx must be initialized by calling
EVP_MD_CTX_init(3)
before calling this function.
EVP_VerifyUpdate
() hashes
cnt bytes of data at
d into the verification context
ctx. This function can be called several
times on the same ctx to include additional
data.
EVP_VerifyFinal
() verifies the data in
ctx using the public key
pkey and against the
siglen bytes at
sigbuf.
EVP_VerifyInit
() initializes a verification
context ctx to use the default implementation
of digest type.
The 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(3),
or a memory leak will occur.
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
ERR_get_error(3).
SEE ALSO
evp(3), EVP_DigestInit(3), EVP_SignInit(3)HISTORY
EVP_VerifyInit
(),
EVP_VerifyUpdate
(), and
EVP_VerifyFinal
() first appeared in SSLeay
0.5.1 and have been available since OpenBSD 2.4.
EVP_VerifyInit_ex
() first appeared in OpenSSL
0.9.7 and has been available since OpenBSD 3.2.
BUGS
Older versions of this documentation wrongly stated that calls toEVP_VerifyUpdate
() could not be made after
calling EVP_VerifyFinal
().
Since the public key is passed in the call to
EVP_SignFinal(3),
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(3).
It is not possible to change the signing parameters using these functions.
The previous two bugs are fixed in the newer functions of the
EVP_DigestVerifyInit(3)
family.June 10, 2019 | Debian |