| EVP_PKEY_verify(3) - phpMan
EVP_PKEY_verify(3SSL) OpenSSL EVP_PKEY_verify(3SSL)
NAME
EVP_PKEY_verify_init, EVP_PKEY_verify - signature verification using a public key
algorithm
SYNOPSIS
#include <openssl/evp.h>
int EVP_PKEY_verify_init(EVP_PKEY_CTX *ctx);
int EVP_PKEY_verify(EVP_PKEY_CTX *ctx,
const unsigned char *sig, size_t siglen,
const unsigned char *tbs, size_t tbslen);
DESCRIPTION
The EVP_PKEY_verify_init() function initializes a public key algorithm context using key
pkey for a signature verification operation.
The EVP_PKEY_verify() function performs a public key verification operation using ctx. The
signature is specified using the sig and siglen parameters. The verified data (i.e. the
data believed originally signed) is specified using the tbs and tbslen parameters.
NOTES
After the call to EVP_PKEY_verify_init() algorithm specific control operations can be
performed to set any appropriate parameters for the operation.
The function EVP_PKEY_verify() can be called more than once on the same context if several
operations are performed using the same parameters.
RETURN VALUES
EVP_PKEY_verify_init() and EVP_PKEY_verify() return 1 if the verification was successful
and 0 if it failed. Unlike other functions the return value 0 from EVP_PKEY_verify() only
indicates that the signature did not not verify successfully (that is tbs did not match
the original data or the signature was of invalid form) it is not an indication of a more
serious error.
A negative value indicates an error other that signature verification failure. In
particular a return value of -2 indicates the operation is not supported by the public key
algorithm.
EXAMPLE
Verify signature using PKCS#1 and SHA256 digest:
#include <openssl/evp.h>
#include <openssl/rsa.h>
EVP_PKEY_CTX *ctx;
unsigned char *md, *sig;
size_t mdlen, siglen;
EVP_PKEY *verify_key;
/* NB: assumes verify_key, sig, siglen md and mdlen are already set up
* and that verify_key is an RSA public key
*/
ctx = EVP_PKEY_CTX_new(verify_key);
if (!ctx)
/* Error occurred */
if (EVP_PKEY_verify_init(ctx) <= 0)
/* Error */
if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PADDING) <= 0)
/* Error */
if (EVP_PKEY_CTX_set_signature_md(ctx, EVP_sha256()) <= 0)
/* Error */
/* Perform operation */
ret = EVP_PKEY_verify(ctx, sig, siglen, md, mdlen);
/* ret == 1 indicates success, 0 verify failure and < 0 for some
* other error.
*/
SEE ALSO
EVP_PKEY_CTX_new(3), EVP_PKEY_encrypt(3), EVP_PKEY_decrypt(3), EVP_PKEY_sign(3),
EVP_PKEY_verify_recover(3), EVP_PKEY_derive(3)
HISTORY
These functions were first added to OpenSSL 1.0.0.
1.0.1t 2016-05-03 EVP_PKEY_verify(3SSL)
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