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>.