EVP_PKEY_verify_init, 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(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 provider(7)/Implicit fetch
for more information about implict fetches.
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)
These functions were added in OpenSSL 1.0.0.
Copyright 2006-2018 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.