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

       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 using OAEP (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 */

SEE ALSO

       d2i_X509(3), ENGINE_by_id(3), EVP_PKEY_CTX_new(3), EVP_PKEY_decrypt(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.

COPYRIGHT

       Copyright 2006-2016 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (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>.