xref: /openssl/doc/man3/EVP_PKEY_encrypt.pod (revision ecb1ed1b)
1=pod
2
3=head1 NAME
4
5EVP_PKEY_encrypt_init_ex,
6EVP_PKEY_encrypt_init, EVP_PKEY_encrypt - encrypt using a public key algorithm
7
8=head1 SYNOPSIS
9
10 #include <openssl/evp.h>
11
12 int EVP_PKEY_encrypt_init(EVP_PKEY_CTX *ctx);
13 int EVP_PKEY_encrypt_init_ex(EVP_PKEY_CTX *ctx, const OSSL_PARAM params[]);
14 int EVP_PKEY_encrypt(EVP_PKEY_CTX *ctx,
15                      unsigned char *out, size_t *outlen,
16                      const unsigned char *in, size_t inlen);
17
18=head1 DESCRIPTION
19
20The EVP_PKEY_encrypt_init() function initializes a public key algorithm
21context using key B<pkey> for an encryption operation.
22
23The EVP_PKEY_encrypt_init_ex() function initializes a public key algorithm
24context using key B<pkey> for an encryption operation and sets the
25algorithm specific B<params>.
26
27The EVP_PKEY_encrypt() function performs a public key encryption operation
28using B<ctx>. The data to be encrypted is specified using the B<in> and
29B<inlen> parameters. If B<out> is B<NULL> then the maximum size of the output
30buffer is written to the B<outlen> parameter. If B<out> is not B<NULL> then
31before the call the B<outlen> parameter should contain the length of the
32B<out> buffer, if the call is successful the encrypted data is written to
33B<out> and the amount of data written to B<outlen>.
34
35=head1 NOTES
36
37After the call to EVP_PKEY_encrypt_init() algorithm specific control
38operations can be performed to set any appropriate parameters for the
39operation.  These operations can be included in the EVP_PKEY_encrypt_init_ex()
40call.
41
42The function EVP_PKEY_encrypt() can be called more than once on the same
43context if several operations are performed using the same parameters.
44
45=head1 RETURN VALUES
46
47EVP_PKEY_encrypt_init(), EVP_PKEY_encrypt_init_ex() and EVP_PKEY_encrypt()
48return 1 for success and 0 or a negative value for failure. In particular a
49return value of -2 indicates the operation is not supported by the public key
50algorithm.
51
52=head1 EXAMPLES
53
54Encrypt data using OAEP (for RSA keys). See also L<PEM_read_PUBKEY(3)> or
55L<d2i_X509(3)> for means to load a public key. You may also simply
56set 'eng = NULL;' to start with the default OpenSSL RSA implementation:
57
58 #include <openssl/evp.h>
59 #include <openssl/rsa.h>
60 #include <openssl/engine.h>
61
62 EVP_PKEY_CTX *ctx;
63 ENGINE *eng;
64 unsigned char *out, *in;
65 size_t outlen, inlen;
66 EVP_PKEY *key;
67
68 /*
69  * NB: assumes eng, key, in, inlen are already set up,
70  * and that key is an RSA public key
71  */
72 ctx = EVP_PKEY_CTX_new(key, eng);
73 if (!ctx)
74     /* Error occurred */
75 if (EVP_PKEY_encrypt_init(ctx) <= 0)
76     /* Error */
77 if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_OAEP_PADDING) <= 0)
78     /* Error */
79
80 /* Determine buffer length */
81 if (EVP_PKEY_encrypt(ctx, NULL, &outlen, in, inlen) <= 0)
82     /* Error */
83
84 out = OPENSSL_malloc(outlen);
85
86 if (!out)
87     /* malloc failure */
88
89 if (EVP_PKEY_encrypt(ctx, out, &outlen, in, inlen) <= 0)
90     /* Error */
91
92 /* Encrypted data is outlen bytes written to buffer out */
93
94=head1 SEE ALSO
95
96L<d2i_X509(3)>,
97L<ENGINE_by_id(3)>,
98L<EVP_PKEY_CTX_new(3)>,
99L<EVP_PKEY_decrypt(3)>,
100L<EVP_PKEY_sign(3)>,
101L<EVP_PKEY_verify(3)>,
102L<EVP_PKEY_verify_recover(3)>,
103L<EVP_PKEY_derive(3)>
104
105=head1 HISTORY
106
107These functions were added in OpenSSL 1.0.0.
108
109=head1 COPYRIGHT
110
111Copyright 2006-2021 The OpenSSL Project Authors. All Rights Reserved.
112
113Licensed under the Apache License 2.0 (the "License").  You may not use
114this file except in compliance with the License.  You can obtain a copy
115in the file LICENSE in the source distribution or at
116L<https://www.openssl.org/source/license.html>.
117
118=cut
119