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| EVP_PKEY_VERIFY(3) | Library Functions Manual | EVP_PKEY_VERIFY(3) |
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
TheEVP_PKEY_verify_init() function
initializes a public key algorithm context using key
ctx->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.
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 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.
EXAMPLES
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; /* * Assumes that 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); 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 some other error. */
SEE ALSO
EVP_PKEY_CTX_new(3), EVP_PKEY_decrypt(3), EVP_PKEY_derive(3), EVP_PKEY_encrypt(3), EVP_PKEY_meth_set_verify(3), EVP_PKEY_sign(3), EVP_PKEY_verify_recover(3)HISTORY
EVP_PKEY_verify_init() and
EVP_PKEY_verify() first appeared in OpenSSL
1.0.0 and have been available since OpenBSD 4.9.| March 23, 2018 | Debian |