NAME
EVP_PKEY_encrypt_init,
EVP_PKEY_encrypt —
encrypt using a public key
algorithm
SYNOPSIS
#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
TheEVP_PKEY_encrypt_init()
function initializes a public key algorithm context using key
ctx->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.
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.
EXAMPLES
Encrypt data using OAEP (for RSA keys). See also
PEM_read_PUBKEY(3) and
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_PKCS1_OAEP_PADDING) <= 0) /* Error */ /* Determine buffer length */ if (EVP_PKEY_encrypt(ctx, NULL, &outlen, in, inlen) <= 0) /* Error */ out = 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 */
SEE ALSO
EVP_PKEY_CTX_new(3), EVP_PKEY_decrypt(3), EVP_PKEY_derive(3), EVP_PKEY_meth_set_encrypt(3), EVP_PKEY_sign(3), EVP_PKEY_verify(3), EVP_PKEY_verify_recover(3)
HISTORY
EVP_PKEY_encrypt_init() and
EVP_PKEY_encrypt() first appeared in OpenSSL 1.0.0
and have been available since OpenBSD 4.9.