Provided by: libssl-doc_1.1.0g-2ubuntu4_all

**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 keypkeyfor an encryption operation. TheEVP_PKEY_encrypt()function performs a public key encryption operation usingctx. The data to be encrypted is specified using theinandinlenparameters. IfoutisNULLthen the maximum size of the output buffer is written to theoutlenparameter. Ifoutis notNULLthen before the call theoutlenparameter should contain the length of theoutbuffer, if the call is successful the encrypted data is written tooutand the amount of data written tooutlen.

**NOTES**

After the call toEVP_PKEY_encrypt_init()algorithm specific control operations can be performed to set any appropriate parameters for the operation. The functionEVP_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()andEVP_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 alsoPEM_read_PUBKEY(3) ord2i_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(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>.