libcrypto/man/EVP_PKEY_encrypt.3

 $NetBSD: EVP_PKEY_encrypt.3,v 1.26 2025/04/16 15:23:15 christos Exp $

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 Title "EVP_PKEY_encrypt 3"  EVP_PKEY_encrypt 3 2025-02-11 3.0.16 OpenSSL
 For nroff, turn off justification. Always turn off hyphenation; it makes
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.nh
 NAME
EVP_PKEY_encrypt_init_ex,
EVP_PKEY_encrypt_init, EVP_PKEY_encrypt - encrypt using a public key algorithm
 SYNOPSIS
 Header "SYNOPSIS" .Vb 1
 #include <openssl/evp.h>
\&
 int EVP_PKEY_encrypt_init(EVP_PKEY_CTX *ctx);
 int EVP_PKEY_encrypt_init_ex(EVP_PKEY_CTX *ctx, const OSSL_PARAM params[]);
 int EVP_PKEY_encrypt(EVP_PKEY_CTX *ctx,
  unsigned char *out, size_t *outlen,
  const unsigned char *in, size_t inlen);
.Ve
 DESCRIPTION
 Header "DESCRIPTION" The EVP_PKEY_encrypt_init() function initializes a public key algorithm
context using key pkey for an encryption operation.

The EVP_PKEY_encrypt_init_ex() function initializes a public key algorithm
context using key pkey for an encryption operation and sets the
algorithm specific params.

The EVP_PKEY_encrypt() function performs a public key encryption operation
using ctx. The data to be encrypted is specified using the in and
\fBinlen 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
\fBout buffer, if the call is successful the encrypted data is written to
\fBout and the amount of data written to outlen.
 NOTES
 Header "NOTES" After the call to EVP_PKEY_encrypt_init() algorithm specific control
operations can be performed to set any appropriate parameters for the
operation. These operations can be included in the EVP_PKEY_encrypt_init_ex()
call.

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"
 Header "RETURN VALUES" \fBEVP_PKEY_encrypt_init(), EVP_PKEY_encrypt_init_ex() 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
 Header "EXAMPLES" Encrypt data using OAEP (for RSA keys). See also PEM_read_PUBKEY\|(3) or
\fBd2i_X509\|(3) for means to load a public key. You may also simply
set 'eng = NULL;' to start with the default OpenSSL RSA implementation:

.Vb 3
 #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 = 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 */
.Ve
 "SEE ALSO"
 Header "SEE ALSO" \fBd2i_X509\|(3),
\fBENGINE_by_id\|(3),
\fBEVP_PKEY_CTX_new\|(3),
\fBEVP_PKEY_decrypt\|(3),
\fBEVP_PKEY_sign\|(3),
\fBEVP_PKEY_verify\|(3),
\fBEVP_PKEY_verify_recover\|(3),
\fBEVP_PKEY_derive\|(3)
 HISTORY
 Header "HISTORY" These functions were added in OpenSSL 1.0.0.
 COPYRIGHT
 Header "COPYRIGHT" Copyright 2006-2022 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (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>.