1RSA_PADDING_ADD_PKCS1_TYPE_1(3ossl) OpenSSLRSA_PADDING_ADD_PKCS1_TYPE_1(3ossl)
2
6 RSA_padding_add_PKCS1_type_1, RSA_padding_check_PKCS1_type_1,
7 RSA_padding_add_PKCS1_type_2, RSA_padding_check_PKCS1_type_2,
8 RSA_padding_add_PKCS1_OAEP, RSA_padding_check_PKCS1_OAEP,
9 RSA_padding_add_PKCS1_OAEP_mgf1, RSA_padding_check_PKCS1_OAEP_mgf1,
10 RSA_padding_add_none, RSA_padding_check_none - asymmetric encryption
11 padding
12
14 #include <openssl/rsa.h>
15 The following functions have been deprecated since OpenSSL 3.0, and can
17 be hidden entirely by defining OPENSSL_API_COMPAT with a suitable
18 version value, see openssl_user_macros(7):
19 int RSA_padding_add_PKCS1_type_1(unsigned char *to, int tlen,
21 const unsigned char *f, int fl);
22 int RSA_padding_check_PKCS1_type_1(unsigned char *to, int tlen,
24 const unsigned char *f, int fl, int rsa_len);
25 int RSA_padding_add_PKCS1_type_2(unsigned char *to, int tlen,
27 const unsigned char *f, int fl);
28 int RSA_padding_check_PKCS1_type_2(unsigned char *to, int tlen,
30 const unsigned char *f, int fl, int rsa_len);
31 int RSA_padding_add_PKCS1_OAEP(unsigned char *to, int tlen,
33 const unsigned char *f, int fl,
34 const unsigned char *p, int pl);
35 int RSA_padding_check_PKCS1_OAEP(unsigned char *to, int tlen,
37 const unsigned char *f, int fl, int rsa_len,
38 const unsigned char *p, int pl);
39 int RSA_padding_add_PKCS1_OAEP_mgf1(unsigned char *to, int tlen,
41 const unsigned char *f, int fl,
42 const unsigned char *p, int pl,
43 const EVP_MD *md, const EVP_MD *mgf1md);
44 int RSA_padding_check_PKCS1_OAEP_mgf1(unsigned char *to, int tlen,
46 const unsigned char *f, int fl, int rsa_len,
47 const unsigned char *p, int pl,
48 const EVP_MD *md, const EVP_MD *mgf1md);
49 int RSA_padding_add_none(unsigned char *to, int tlen,
51 const unsigned char *f, int fl);
52 int RSA_padding_check_none(unsigned char *to, int tlen,
54 const unsigned char *f, int fl, int rsa_len);
55
57 All of the functions described on this page are deprecated.
58 Applications should instead use the EVP PKEY APIs.
59 The RSA_padding_xxx_xxx() functions are called from the RSA encrypt,
61 decrypt, sign and verify functions. Normally they should not be called
62 from application programs.
63 However, they can also be called directly to implement padding for
65 other asymmetric ciphers. RSA_padding_add_PKCS1_OAEP() and
66 RSA_padding_check_PKCS1_OAEP() may be used in an application combined
67 with RSA_NO_PADDING in order to implement OAEP with an encoding
68 parameter.
69 RSA_padding_add_xxx() encodes fl bytes from f so as to fit into tlen
71 bytes and stores the result at to. An error occurs if fl does not meet
72 the size requirements of the encoding method.
73 The following encoding methods are implemented:
75 PKCS1_type_1
77 PKCS #1 v2.0 EMSA-PKCS1-v1_5 (PKCS #1 v1.5 block type 1); used for
78 signatures
79 PKCS1_type_2
81 PKCS #1 v2.0 EME-PKCS1-v1_5 (PKCS #1 v1.5 block type 2)
82 PKCS1_OAEP
84 PKCS #1 v2.0 EME-OAEP
85 none
87 simply copy the data
88 The random number generator must be seeded prior to calling
90 RSA_padding_add_xxx(). If the automatic seeding or reseeding of the
91 OpenSSL CSPRNG fails due to external circumstances (see RAND(7)), the
92 operation will fail.
93 RSA_padding_check_xxx() verifies that the fl bytes at f contain a valid
95 encoding for a rsa_len byte RSA key in the respective encoding method
96 and stores the recovered data of at most tlen bytes (for
97 RSA_NO_PADDING: of size tlen) at to.
98 For RSA_padding_xxx_OAEP(), p points to the encoding parameter of
100 length pl. p may be NULL if pl is 0.
101 For RSA_padding_xxx_OAEP_mgf1(), md points to the md hash, if md is
103 NULL that means md=sha1, and mgf1md points to the mgf1 hash, if mgf1md
104 is NULL that means mgf1md=md.
105
107 The RSA_padding_add_xxx() functions return 1 on success, 0 on error.
108 The RSA_padding_check_xxx() functions return the length of the
109 recovered data, -1 on error. Error codes can be obtained by calling
110 ERR_get_error(3).
111
113 The result of RSA_padding_check_PKCS1_type_2() is exactly the
114 information which is used to mount a classical Bleichenbacher padding
115 oracle attack. This is an inherent weakness in the PKCS #1 v1.5 padding
116 design. Prefer PKCS1_OAEP padding. If that is not possible, the result
117 of RSA_padding_check_PKCS1_type_2() should be checked in constant time
118 if it matches the expected length of the plaintext and additionally
119 some application specific consistency checks on the plaintext need to
120 be performed in constant time. If the plaintext is rejected it must be
121 kept secret which of the checks caused the application to reject the
122 message. Do not remove the zero-padding from the decrypted raw RSA
123 data which was computed by RSA_private_decrypt() with RSA_NO_PADDING,
124 as this would create a small timing side channel which could be used to
125 mount a Bleichenbacher attack against any padding mode including
126 PKCS1_OAEP.
127 You should prefer the use of EVP PKEY APIs for PKCS#1 v1.5 decryption
129 as they implement the necessary workarounds internally.
130
132 RSA_public_encrypt(3), RSA_private_decrypt(3), RSA_sign(3),
133 RSA_verify(3), RAND(7)
134
136 All of these functions were deprecated in OpenSSL 3.0.
137
139 Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
140 Licensed under the Apache License 2.0 (the "License"). You may not use
142 this file except in compliance with the License. You can obtain a copy
143 in the file LICENSE in the source distribution or at
144 <https://www.openssl.org/source/license.html>.
1453.1.1 2023-08-31RSA_PADDING_ADD_PKCS1_TYPE_1(3ossl)