EVP_PKEY_decrypt

NAME

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() 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.  

NOTES

The function EVP_PKEY_decrypt() can be called more than once on the same context if several operations are performed using the same parameters.  

RETURN VALUES

EXAMPLE

 #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

HISTORY