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rc4.c
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1 /*
2  * dlls/rsaenh/rc4.c
3  * RC4 functions
4  *
5  * Copyright 2004 Michael Jung
6  * Based on public domain code by Tom St Denis (tomstdenis@iahu.ca)
7  *
8  * This library is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * This library is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with this library; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
21  */
22 
23 /*
24  * This file contains code from the LibTomCrypt cryptographic
25  * library written by Tom St Denis (tomstdenis@iahu.ca). LibTomCrypt
26  * is in the public domain. The code in this file is tailored to
27  * special requirements. Take a look at http://libtomcrypt.org for the
28  * original version.
29  */
30 
31 #include "tomcrypt.h"
32 
34 {
35  /* set keysize to zero */
36  prng->rc4.x = 0;
37 
38  return CRYPT_OK;
39 }
40 
41 int rc4_add_entropy(const unsigned char *buf, unsigned long len, prng_state *prng)
42 {
43  /* trim as required */
44  if (prng->rc4.x + len > 256) {
45  if (prng->rc4.x == 256) {
46  /* I can't possibly accept another byte, ok maybe a mint wafer... */
47  return CRYPT_OK;
48  } else {
49  /* only accept part of it */
50  len = 256 - prng->rc4.x;
51  }
52  }
53 
54  while (len--) {
55  prng->rc4.buf[prng->rc4.x++] = *buf++;
56  }
57 
58  return CRYPT_OK;
59 }
60 
62 {
63  unsigned char key[256], tmp, *s;
64  int keylen, x, y, j;
65 
66  /* extract the key */
67  s = prng->rc4.buf;
68  memcpy(key, s, 256);
69  keylen = prng->rc4.x;
70 
71  /* make RC4 perm and shuffle */
72  for (x = 0; x < 256; x++) {
73  s[x] = x;
74  }
75 
76  for (j = x = y = 0; x < 256; x++) {
77  y = (y + prng->rc4.buf[x] + key[j++]) & 255;
78  if (j == keylen) {
79  j = 0;
80  }
81  tmp = s[x]; s[x] = s[y]; s[y] = tmp;
82  }
83  prng->rc4.x = 0;
84  prng->rc4.y = 0;
85 
86  return CRYPT_OK;
87 }
88 
89 unsigned long rc4_read(unsigned char *buf, unsigned long len, prng_state *prng)
90 {
91  unsigned char x, y, *s, tmp;
92  unsigned long n;
93 
94  n = len;
95  x = prng->rc4.x;
96  y = prng->rc4.y;
97  s = prng->rc4.buf;
98  while (len--) {
99  x = (x + 1) & 255;
100  y = (y + s[x]) & 255;
101  tmp = s[x]; s[x] = s[y]; s[y] = tmp;
102  tmp = (s[x] + s[y]) & 255;
103  *buf++ ^= s[tmp];
104  }
105  prng->rc4.x = x;
106  prng->rc4.y = y;
107  return n;
108 }
GLenum GLuint GLenum GLsizei const GLchar * buf
Definition: glext.h:7751
GLdouble n
Definition: glext.h:7729
GLint GLint GLint GLint GLint x
Definition: gl.h:1548
GLsizei GLenum const GLvoid GLsizei GLenum GLbyte GLbyte GLbyte GLdouble GLdouble GLdouble GLfloat GLfloat GLfloat GLint GLint GLint GLshort GLshort GLshort GLubyte GLubyte GLubyte GLuint GLuint GLuint GLushort GLushort GLushort GLbyte GLbyte GLbyte GLbyte GLdouble GLdouble GLdouble GLdouble GLfloat GLfloat GLfloat GLfloat GLint GLint GLint GLint GLshort GLshort GLshort GLshort GLubyte GLubyte GLubyte GLubyte GLuint GLuint GLuint GLuint GLushort GLushort GLushort GLushort GLboolean const GLdouble const GLfloat const GLint const GLshort const GLbyte const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLdouble const GLfloat const GLfloat const GLint const GLint const GLshort const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort GLenum GLenum GLenum GLfloat GLenum GLint GLenum GLenum GLenum GLfloat GLenum GLenum GLint GLenum GLfloat GLenum GLint GLint GLushort GLenum GLenum GLfloat GLenum GLenum GLint GLfloat const GLubyte GLenum GLenum GLenum const GLfloat GLenum GLenum const GLint GLenum GLint GLint GLsizei GLsizei GLint GLenum GLenum const GLvoid GLenum GLenum const GLfloat GLenum GLenum const GLint GLenum GLenum const GLdouble GLenum GLenum const GLfloat GLenum GLenum const GLint GLsizei GLuint GLfloat GLuint GLbitfield GLfloat GLint GLuint GLboolean GLenum GLfloat GLenum GLbitfield GLenum GLfloat GLfloat GLint GLint const GLfloat GLenum GLfloat GLfloat GLint GLint GLfloat GLfloat GLint GLint const GLfloat GLint GLfloat GLfloat GLint GLfloat GLfloat GLint GLfloat GLfloat const GLdouble const GLfloat const GLdouble const GLfloat GLint GLint GLint j
Definition: glfuncs.h:250
int rc4_ready(prng_state *prng)
Definition: rc4.c:61
int rc4_start(prng_state *prng)
Definition: rc4.c:33
#define memcpy(s1, s2, n)
Definition: mkisofs.h:878
GLenum GLsizei len
Definition: glext.h:6722
GLdouble s
Definition: gl.h:2039
struct rc4_prng rc4
Definition: tomcrypt.h:168
int rc4_add_entropy(const unsigned char *buf, unsigned long len, prng_state *prng)
Definition: rc4.c:41
GLint GLint GLint GLint GLint GLint y
Definition: gl.h:1548
unsigned long rc4_read(unsigned char *buf, unsigned long len, prng_state *prng)
Definition: rc4.c:89
Definition: path.c:42