3 * $Id: rsa-pub.c,v 1.1 2000/07/01 11:23:52 mdw Exp $
5 * [RSA encryption with padding *
6 * (c) 2000 Straylight/Edgeware
9 /*----- Licensing notice --------------------------------------------------*
11 * This file is part of Catacomb.
13 * Catacomb is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU Library General Public License as
15 * published by the Free Software Foundation; either version 2 of the
16 * License, or (at your option) any later version.
18 * Catacomb is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU Library General Public License for more details.
23 * You should have received a copy of the GNU Library General Public
24 * License along with Catacomb; if not, write to the Free
25 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
29 /*----- Revision history --------------------------------------------------*
32 * Revision 1.1 2000/07/01 11:23:52 mdw
33 * Public-key operations, for symmetry with `rsa-priv.c'. Functions for
34 * doing padded RSA encryption and signature verification.
38 /*----- Header files ------------------------------------------------------*/
40 #include <mLib/alloc.h>
41 #include <mLib/bits.h>
42 #include <mLib/dstr.h>
48 /*----- Public key operations ---------------------------------------------*/
50 /* --- @rsa_pubcreate@ --- *
52 * Arguments: @rsa_pubctx *rd@ = pointer to an RSA public key context
53 * @rsa_pub *rp@ = pointer to RSA public key
57 * Use: Initializes an RSA public-key context.
60 void rsa_pubcreate(rsa_pubctx
*rd
, rsa_pub
*rp
)
63 mpmont_create(&rd
->mm
, rp
->n
);
66 /* --- @rsa_pubdestroy@ --- *
68 * Arguments: @rsa_pubctx *rd@ = pointer to an RSA public key context
72 * Use: Destroys an RSA public-key context.
75 void rsa_pubdestroy(rsa_pubctx
*rd
)
77 mpmont_destroy(&rd
->mm
);
80 /* --- @rsa_pubop@ --- *
82 * Arguments: @rsa_pubctx *rd@ = pointer to an RSA public key context
83 * @mp *d@ = destination
84 * @mp *p@ = input message
86 * Returns: The transformed output message.
88 * Use: Performs an RSA public key operation.
91 mp
*rsa_pubop(rsa_pubctx
*rd
, mp
*d
, mp
*p
)
93 return (mpmont_exp(&rd
->mm
, d
, p
, rd
->rp
->e
));
96 /* --- @rsa_qpubop@ --- *
98 * Arguments: @rsa_pub *rp@ = pointer to RSA parameters
99 * @mp *d@ = destination
100 * @mp *p@ = input message
102 * Returns: Correctly transformed output message.
104 * Use: Performs an RSA public key operation.
107 mp
*rsa_qpubop(rsa_pub
*rp
, mp
*d
, mp
*c
)
110 rsa_pubcreate(&rd
, rp
);
111 d
= rsa_pubop(&rd
, d
, c
);
116 /*----- Operations with padding -------------------------------------------*/
118 /* --- @rsa_encrypt@ --- *
120 * Arguments: @rsa_pubctx *rp@ = pointer to an RSA public key context
121 * @const void *m@ = pointer to input message
122 * @size_t sz@ = size of input message
123 * @dstr *d@ = pointer to output string
124 * @rsa_encodeproc e@ = encoding procedure
125 * @void *earg@ = argument pointer for encoding procedure
127 * Returns: The length of the output string if successful, negative on
130 * Use: Does RSA encryption.
133 int rsa_encrypt(rsa_pubctx
*rp
, const void *m
, size_t sz
,
134 dstr
*d
, rsa_encodeproc e
, void *earg
)
137 size_t n
= mp_octets(rp
->rp
->n
);
141 /* --- Sort out some space --- */
147 /* --- Do the packing --- */
149 if ((rc
= e(m
, sz
, p
, n
, earg
)) < 0)
152 /* --- Do the encryption --- */
154 x
= mp_loadb(MP_NEWSEC
, p
, n
);
155 x
= rsa_pubop(rp
, x
, x
);
162 /* --- @rsa_verify@ --- *
164 * Arguments: @rsa_pubctx *rp@ = pointer to an RSA public key context
165 * @const void *m@ = pointer to input message
166 * @size_t sz@ = size of input message
167 * @dstr *d@ = pointer to output string
168 * @rsa_decodeproc e@ = decoding procedure
169 * @void *earg@ = argument pointer for decoding procedure
171 * Returns: The length of the output string if successful, negative on
174 * Use: Does RSA signature verification.
177 int rsa_verify(rsa_pubctx
*rp
, const void *m
, size_t sz
,
178 dstr
*d
, rsa_decodeproc e
, void *earg
)
181 size_t n
= mp_octets(rp
->rp
->n
);
185 /* --- Do the exponentiation --- */
187 p
= x_alloc(d
->a
, n
);
188 x
= mp_loadb(MP_NEW
, m
, sz
);
189 x
= rsa_pubop(rp
, x
, x
);
193 /* --- Do the decoding --- */
195 rc
= e(p
, n
, d
, earg
);
200 /*----- That's all, folks -------------------------------------------------*/