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(EVP_PKEY_CTX *ctx, unsigned char *out, size_t *outlen, const unsigned char *in, size_t inlen);
OpenSSL EVP_PKEY_decrypt(3openssl)
NAME
EVP_PKEY_decrypt_init, EVP_PKEY_decrypt - decrypt using a public key
algorithm
SYNOPSIS
#include <openssl/evp.h>
int EVP_PKEY_decrypt_init(EVP_PKEY_CTX *ctx);
int EVP_PKEY_decrypt(EVP_PKEY_CTX *ctx,
unsigned char *out, size_t *outlen,
const unsigned char *in, size_t inlen);
DESCRIPTION
The EVP_PKEY_decrypt_init() function initializes a public key algorithm
context using key pkey for a decryption operation.
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 maximum size of the
output buffer is written to the outlen parameter. If out is not NULL
then before the call the outlen parameter should contain the length of
the out buffer, if the call is successful the decrypted data is written
to out and the amount of data written to outlen.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+--------------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+--------------------------+
|Availability | library/security/openssl |
+---------------+--------------------------+
|Stability | Pass-through uncommitted |
+---------------+--------------------------+
NOTES
After the call to EVP_PKEY_decrypt_init() algorithm specific control
operations can be performed to set any appropriate parameters for the
operation.
The function EVP_PKEY_decrypt() can be called more than once on the
same context if several operations are performed using the same
parameters.
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from
https://www.openssl.org/source/openssl-1.0.2ze.tar.gz.
Further information about this software can be found on the open source
community website at https://www.openssl.org/.
RETURN VALUES
EVP_PKEY_decrypt_init() 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.
EXAMPLE
Decrypt data using OAEP (for RSA keys):
#include <openssl/evp.h>
#include <openssl/rsa.h>
EVP_PKEY_CTX *ctx;
unsigned char *out, *in;
size_t outlen, inlen;
EVP_PKEY *key;
/* NB: assumes key in, inlen are already set up
* and that key is an RSA private key
*/
ctx = EVP_PKEY_CTX_new(key);
if (!ctx)
/* Error occurred */
if (EVP_PKEY_decrypt_init(ctx) <= 0)
/* Error */
if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_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 */
SEE ALSO
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)
HISTORY
These functions were first added to OpenSSL 1.0.0.
1.0.2ze 2022-05-03
EVP_PKEY_decrypt(3openssl)