EVP_PKEY_verify_init, EVP_PKEY_verify_init_ex, EVP_PKEY_verify - signature
verification using a public key algorithm
#include <openssl/evp.h>
int EVP_PKEY_verify_init(EVP_PKEY_CTX *ctx);
int EVP_PKEY_verify_init_ex(EVP_PKEY_CTX *ctx, const OSSL_PARAM params[]);
int EVP_PKEY_verify(EVP_PKEY_CTX *ctx,
const unsigned char *sig, size_t siglen,
const unsigned char *tbs, size_t tbslen);
EVP_PKEY_verify_init() initializes a public key algorithm context
ctx for signing using the algorithm given when the context was created
using
EVP_PKEY_CTX_new(3) or variants thereof. The algorithm is used to
fetch a
EVP_SIGNATURE method implicitly, see "Implicit fetch"
in
provider(7) for more information about implicit fetches.
EVP_PKEY_verify_init_ex() is the same as
EVP_PKEY_verify_init()
but additionally sets the passed parameters
params on the context
before returning.
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.
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.
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 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.
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, NULL /* no engine */);
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.
*/
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)
The
EVP_PKEY_verify_init() and
EVP_PKEY_verify() functions were
added in OpenSSL 1.0.0.
The
EVP_PKEY_verify_init_ex() function was added in OpenSSL 3.0.
Copyright 2006-2021 The OpenSSL Project Authors. All Rights Reserved.
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
<
https://www.openssl.org/source/license.html>.