EVP_VerifyInit(3)
- NetBSD Manual Pages
EVP_VerifyInit(3) OpenSSL EVP_VerifyInit(3)
NAME
EVP_VerifyInit, EVP_VerifyUpdate, EVP_VerifyFinal - EVP
signature verification functions
LIBRARY
libcrypto, -lcrypto
SYNOPSIS
#include <openssl/evp.h>
void EVP_VerifyInit(EVP_MD_CTX *ctx, const EVP_MD *type);
void 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);
DESCRIPTION
The EVP signature verification routines are a high level
interface to digital signatures.
EVP_VerifyInit() initializes a verification context ctx to
using digest type: this will typically be supplied by a
function such as EVP_sha1().
EVP_VerifyUpdate() hashes cnt bytes of data at d into the
verification context ctx. This function can be called sev-
eral times on the same ctx to include additional data.
EVP_VerifyFinal() verifies the data in ctx using the pub-
lic key pkey and against the siglen bytes at sigbuf. After
calling EVP_VerifyFinal() no additional calls to EVP_Veri-
fyUpdate() can be made, but EVP_VerifyInit() can be called
to initialize a new verification operation.
RETURN VALUES
EVP_VerifyInit() and EVP_VerifyUpdate() do not return val-
ues.
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).
NOTES
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.
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 EVP_DigestInit(3)
.
2002-07-31 0.9.6g 1
EVP_VerifyInit(3) OpenSSL EVP_VerifyInit(3)
BUGS
Several of the functions do not return values: maybe they
should. Although the internal digest operations will never
fail some future hardware based operations might.
SEE ALSO
openssl_evp(3), EVP_SignInit(3), EVP_DigestInit(3),
openssl_err(3), openssl_evp(3), openssl_hmac(3), md2(3),
openssl_md5(3), openssl_mdc2(3), openssl_ripemd(3),
openssl_sha(3), openssl_dgst(1)
HISTORY
EVP_VerifyInit(), EVP_VerifyUpdate() and EVP_VerifyFinal()
are available in all versions of SSLeay and OpenSSL.
2002-07-31 0.9.6g 2
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