1RSA_PADDING_ADD_PKCS1_TYPE_1(3) OpenSSL RSA_PADDING_ADD_PKCS1_TYPE_1(3)
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_SSLv23, RSA_padding_check_SSLv23, RSA_padding_add_none,
11 RSA_padding_check_none - asymmetric encryption padding
12
14 #include <openssl/rsa.h>
15 int RSA_padding_add_PKCS1_type_1(unsigned char *to, int tlen,
17 const unsigned char *f, int fl);
18 int RSA_padding_check_PKCS1_type_1(unsigned char *to, int tlen,
20 const unsigned char *f, int fl, int rsa_len);
21 int RSA_padding_add_PKCS1_type_2(unsigned char *to, int tlen,
23 const unsigned char *f, int fl);
24 int RSA_padding_check_PKCS1_type_2(unsigned char *to, int tlen,
26 const unsigned char *f, int fl, int rsa_len);
27 int RSA_padding_add_PKCS1_OAEP(unsigned char *to, int tlen,
29 const unsigned char *f, int fl,
30 const unsigned char *p, int pl);
31 int RSA_padding_check_PKCS1_OAEP(unsigned char *to, int tlen,
33 const unsigned char *f, int fl, int rsa_len,
34 const unsigned char *p, int pl);
35 int RSA_padding_add_PKCS1_OAEP_mgf1(unsigned char *to, int tlen,
37 const unsigned char *f, int fl,
38 const unsigned char *p, int pl,
39 const EVP_MD *md, const EVP_MD *mgf1md);
40 int RSA_padding_check_PKCS1_OAEP_mgf1(unsigned char *to, int tlen,
42 const unsigned char *f, int fl, int rsa_len,
43 const unsigned char *p, int pl,
44 const EVP_MD *md, const EVP_MD *mgf1md);
45 int RSA_padding_add_SSLv23(unsigned char *to, int tlen,
47 const unsigned char *f, int fl);
48 int RSA_padding_check_SSLv23(unsigned char *to, int tlen,
50 const unsigned char *f, int fl, int rsa_len);
51 int RSA_padding_add_none(unsigned char *to, int tlen,
53 const unsigned char *f, int fl);
54 int RSA_padding_check_none(unsigned char *to, int tlen,
56 const unsigned char *f, int fl, int rsa_len);
57
59 The RSA_padding_xxx_xxx() functions are called from the RSA encrypt,
60 decrypt, sign and verify functions. Normally they should not be called
61 from application programs.
62 However, they can also be called directly to implement padding for
64 other asymmetric ciphers. RSA_padding_add_PKCS1_OAEP() and
65 RSA_padding_check_PKCS1_OAEP() may be used in an application combined
66 with RSA_NO_PADDING in order to implement OAEP with an encoding
67 parameter.
68 RSA_padding_add_xxx() encodes fl bytes from f so as to fit into tlen
70 bytes and stores the result at to. An error occurs if fl does not meet
71 the size requirements of the encoding method.
72 The following encoding methods are implemented:
74 PKCS1_type_1
76 PKCS #1 v2.0 EMSA-PKCS1-v1_5 (PKCS #1 v1.5 block type 1); used for
77 signatures
78 PKCS1_type_2
80 PKCS #1 v2.0 EME-PKCS1-v1_5 (PKCS #1 v1.5 block type 2)
81 PKCS1_OAEP
83 PKCS #1 v2.0 EME-OAEP
84 SSLv23
86 PKCS #1 EME-PKCS1-v1_5 with SSL-specific modification
87 none
89 simply copy the data
90 The random number generator must be seeded prior to calling
92 RSA_padding_add_xxx(). If the automatic seeding or reseeding of the
93 OpenSSL CSPRNG fails due to external circumstances (see RAND(7)), the
94 operation will fail.
95 RSA_padding_check_xxx() verifies that the fl bytes at f contain a valid
97 encoding for a rsa_len byte RSA key in the respective encoding method
98 and stores the recovered data of at most tlen bytes (for
99 RSA_NO_PADDING: of size tlen) at to.
100 For RSA_padding_xxx_OAEP(), p points to the encoding parameter of
102 length pl. p may be NULL if pl is 0.
103 For RSA_padding_xxx_OAEP_mgf1(), md points to the md hash, if md is
105 NULL that means md=sha1, and mgf1md points to the mgf1 hash, if mgf1md
106 is NULL that means mgf1md=md.
107
109 The RSA_padding_add_xxx() functions return 1 on success, 0 on error.
110 The RSA_padding_check_xxx() functions return the length of the
111 recovered data, -1 on error. Error codes can be obtained by calling
112 ERR_get_error(3).
113
115 The result of RSA_padding_check_PKCS1_type_2() is a very sensitive
116 information which can potentially be used to mount a Bleichenbacher
117 padding oracle attack. This is an inherent weakness in the PKCS #1 v1.5
118 padding design. Prefer PKCS1_OAEP padding. If that is not possible, the
119 result of RSA_padding_check_PKCS1_type_2() should be checked in
120 constant time if it matches the expected length of the plaintext and
121 additionally some application specific consistency checks on the
122 plaintext need to be performed in constant time. If the plaintext is
123 rejected it must be kept secret which of the checks caused the
124 application to reject the message. Do not remove the zero-padding from
125 the decrypted raw RSA data which was computed by RSA_private_decrypt()
126 with RSA_NO_PADDING, as this would create a small timing side channel
127 which could be used to mount a Bleichenbacher attack against any
128 padding mode including PKCS1_OAEP.
129
131 RSA_public_encrypt(3), RSA_private_decrypt(3), RSA_sign(3),
132 RSA_verify(3), RAND(7)
133
135 Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
136 Licensed under the OpenSSL license (the "License"). You may not use
138 this file except in compliance with the License. You can obtain a copy
139 in the file LICENSE in the source distribution or at
140 <https://www.openssl.org/source/license.html>.
1411.1.1q 2023-07-20 RSA_PADDING_ADD_PKCS1_TYPE_1(3)