EVP_PKEY_encrypt (3)
Leading comments
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NAME
EVP_PKEY_encrypt_init, EVP_PKEY_encrypt - encrypt using a public key algorithmSYNOPSIS
#include <openssl/evp.h>
int EVP_PKEY_encrypt_init(EVP_PKEY_CTX *ctx);
int EVP_PKEY_encrypt(EVP_PKEY_CTX *ctx,
unsigned char *out, size_t *outlen,
const unsigned char *in, size_t inlen);
DESCRIPTION
The EVP_PKEY_encrypt_init() function initializes a public key algorithm context using key pkey for an encryption operation.The EVP_PKEY_encrypt() function performs a public key encryption operation using ctx. The data to be encrypted 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 encrypted data is written to
out and the amount of data written to outlen.
NOTES
After the call to EVP_PKEY_encrypt_init() algorithm specific control operations can be performed to set any appropriate parameters for the operation.The function EVP_PKEY_encrypt() can be called more than once on the same context if several operations are performed using the same parameters.
RETURN VALUES
EVP_PKEY_encrypt_init() and EVP_PKEY_encrypt() 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
Encrypt data usingOAEP
(for RSA
keys). See also PEM_read_PUBKEY(3) or
d2i_X509(3) for means to load a public key. You may also simply
set 'eng = NULL
;' to start with the default OpenSSL RSA
implementation:
#include <openssl/evp.h>
#include <openssl/rsa.h>
#include <openssl/engine.h>
EVP_PKEY_CTX *ctx;
ENGINE *eng;
unsigned char *out, *in;
size_t outlen, inlen;
EVP_PKEY *key;
/* NB: assumes eng, key, in, inlen are already set up,
* and that key is an RSA public key
*/
ctx = EVP_PKEY_CTX_new(key,eng);
if (!ctx)
/* Error occurred */
if (EVP_PKEY_encrypt_init(ctx) <= 0)
/* Error */
if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_OAEP_PADDING) <= 0)
/* Error */
/* Determine buffer length */
if (EVP_PKEY_encrypt(ctx, NULL, &outlen, in, inlen) <= 0)
/* Error */
out = OPENSSL_malloc(outlen);
if (!out)
/* malloc failure */
if (EVP_PKEY_encrypt(ctx, out, &outlen, in, inlen) <= 0)
/* Error */
/* Encrypted data is outlen bytes written to buffer out */