EVP_PKEY_decrypt_init, EVP_PKEY_decrypt_init_ex, EVP_PKEY_decrypt - decrypt
using a public key algorithm
#include <openssl/evp.h>
int EVP_PKEY_decrypt_init(EVP_PKEY_CTX *ctx);
int EVP_PKEY_decrypt_init_ex(EVP_PKEY_CTX *ctx, const OSSL_PARAM params[]);
int EVP_PKEY_decrypt(EVP_PKEY_CTX *ctx,
unsigned char *out, size_t *outlen,
const unsigned char *in, size_t inlen);
The
EVP_PKEY_decrypt_init() function initializes a public key algorithm
context using key
pkey for a decryption operation.
The
EVP_PKEY_decrypt_init_ex() function initializes a public key
algorithm context using key
pkey for a decryption operation and sets
the algorithm specific
params.
The
EVP_PKEY_decrypt() function performs a public key decryption
operation using
ctx. The data to be decrypted is specified using the
in and
inlen parameters. If
out is NULL then the minimum
required size of the output buffer is written to the
*outlen parameter.
If
out is not NULL then before the call the
*outlen parameter must
contain the length of the
out buffer. If the call is successful the
decrypted data is written to
out and the amount of the decrypted data
written to
*outlen, otherwise an error is returned.
After the call to
EVP_PKEY_decrypt_init() algorithm specific control
operations can be performed to set any appropriate parameters for the
operation. These operations can be included in the
EVP_PKEY_decrypt_init_ex() call.
The function
EVP_PKEY_decrypt() can be called more than once on the same
context if several operations are performed using the same parameters.
EVP_PKEY_decrypt_init(),
EVP_PKEY_decrypt_init_ex() and
EVP_PKEY_decrypt() return 1 for success and 0 or a negative value for
failure. In particular a return value of -2 indicates the operation is not
supported by the public key algorithm.
Decrypt data using OAEP (for RSA keys):
#include <openssl/evp.h>
#include <openssl/rsa.h>
EVP_PKEY_CTX *ctx;
ENGINE *eng;
unsigned char *out, *in;
size_t outlen, inlen;
EVP_PKEY *key;
/*
* NB: assumes key, eng, in, inlen are already set up
* and that key is an RSA private key
*/
ctx = EVP_PKEY_CTX_new(key, eng);
if (!ctx)
/* Error occurred */
if (EVP_PKEY_decrypt_init(ctx) <= 0)
/* Error */
if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_OAEP_PADDING) <= 0)
/* Error */
/* Determine buffer length */
if (EVP_PKEY_decrypt(ctx, NULL, &outlen, in, inlen) <= 0)
/* Error */
out = OPENSSL_malloc(outlen);
if (!out)
/* malloc failure */
if (EVP_PKEY_decrypt(ctx, out, &outlen, in, inlen) <= 0)
/* Error */
/* Decrypted data is outlen bytes written to buffer out */
EVP_PKEY_CTX_new(3),
EVP_PKEY_encrypt(3),
EVP_PKEY_sign(3),
EVP_PKEY_verify(3),
EVP_PKEY_verify_recover(3),
EVP_PKEY_derive(3)
These functions were added in OpenSSL 1.0.0.
Copyright 2006-2022 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>.