<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html><head><meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1"> <title>sapphire.cpp Source File</title> <link href="doxygen.css" rel="stylesheet" type="text/css"> </head><body> <!-- Generated by Doxygen 1.2.15 --> <center> <a class="qindex" href="index.html">Main Page</a> <a class="qindex" href="namespaces.html">Namespace List</a> <a class="qindex" href="hierarchy.html">Class Hierarchy</a> <a class="qindex" href="classes.html">Alphabetical List</a> <a class="qindex" href="annotated.html">Compound List</a> <a class="qindex" href="files.html">File List</a> <a class="qindex" href="functions.html">Compound Members</a> </center> <hr><h1>sapphire.cpp</h1><div class="fragment"><pre>00001 <font class="comment">/* sapphire.cpp -- the Saphire II stream cipher class.</font> 00002 <font class="comment"> Dedicated to the Public Domain the author and inventor:</font> 00003 <font class="comment"> (Michael Paul Johnson). This code comes with no warranty.</font> 00004 <font class="comment"> Use it at your own risk.</font> 00005 <font class="comment"> Ported from the Pascal implementation of the Sapphire Stream</font> 00006 <font class="comment"> Cipher 9 December 1994.</font> 00007 <font class="comment"> Added hash pre- and post-processing 27 December 1994.</font> 00008 <font class="comment"> Modified initialization to make index variables key dependent,</font> 00009 <font class="comment"> made the output function more resistant to cryptanalysis,</font> 00010 <font class="comment"> and renamed to Sapphire II 2 January 1995</font> 00011 <font class="comment">*/</font> 00012 00013 00014 <font class="preprocessor">#ifdef WIN32</font> 00015 <font class="preprocessor"></font><font class="preprocessor">#include <memory.h></font> 00016 <font class="preprocessor">#endif</font> 00017 <font class="preprocessor"></font> 00018 <font class="preprocessor">#ifdef UNIX</font> 00019 <font class="preprocessor"></font><font class="preprocessor">#include <memory.h></font> 00020 <font class="preprocessor">#include <unistd.h></font> 00021 <font class="preprocessor">#else</font> 00022 <font class="preprocessor"></font><font class="preprocessor">#ifndef _MSC_VER</font> 00023 <font class="preprocessor"></font><font class="preprocessor">#include <mem.h></font> 00024 <font class="preprocessor">#endif</font> 00025 <font class="preprocessor"></font><font class="preprocessor">#endif</font> 00026 <font class="preprocessor"></font> 00027 <font class="preprocessor">#ifdef _WIN32_WCE</font> 00028 <font class="preprocessor"></font><font class="preprocessor">#include <string.h></font> 00029 <font class="preprocessor">#endif</font> 00030 <font class="preprocessor"></font> 00031 <font class="preprocessor">#include "sapphire.h"</font> 00032 00033 <font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> sapphire::keyrand(<font class="keywordtype">int</font> limit, 00034 <font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> *user_key, 00035 <font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> keysize, 00036 <font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> *rsum, 00037 <font class="keywordtype">unsigned</font> *keypos) 00038 { 00039 <font class="keywordtype">unsigned</font> u, <font class="comment">// Value from 0 to limit to return.</font> 00040 retry_limiter, <font class="comment">// No infinite loops allowed.</font> 00041 mask; <font class="comment">// Select just enough bits.</font> 00042 00043 <font class="keywordflow">if</font> (!limit) <font class="keywordflow">return</font> 0; <font class="comment">// Avoid divide by zero error.</font> 00044 retry_limiter = 0; 00045 mask = 1; <font class="comment">// Fill mask with enough bits to cover</font> 00046 <font class="keywordflow">while</font> (mask < (unsigned)limit) <font class="comment">// the desired range.</font> 00047 mask = (mask << 1) + 1; 00048 <font class="keywordflow">do</font> 00049 { 00050 *rsum = cards[*rsum] + user_key[(*keypos)++]; 00051 <font class="keywordflow">if</font> (*keypos >= keysize) 00052 { 00053 *keypos = 0; <font class="comment">// Recycle the user key.</font> 00054 *rsum += keysize; <font class="comment">// key "aaaa" != key "aaaaaaaa"</font> 00055 } 00056 u = mask & *rsum; 00057 <font class="keywordflow">if</font> (++retry_limiter > 11) 00058 u %= limit; <font class="comment">// Prevent very rare long loops.</font> 00059 } 00060 <font class="keywordflow">while</font> (u > (unsigned)limit); 00061 <font class="keywordflow">return</font> u; 00062 } 00063 00064 <font class="keywordtype">void</font> sapphire::initialize(<font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> *key, <font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> keysize) 00065 { 00066 <font class="comment">// Key size may be up to 256 bytes.</font> 00067 <font class="comment">// Pass phrases may be used directly, with longer length</font> 00068 <font class="comment">// compensating for the low entropy expected in such keys.</font> 00069 <font class="comment">// Alternatively, shorter keys hashed from a pass phrase or</font> 00070 <font class="comment">// generated randomly may be used. For random keys, lengths</font> 00071 <font class="comment">// of from 4 to 16 bytes are recommended, depending on how</font> 00072 <font class="comment">// secure you want this to be.</font> 00073 00074 <font class="keywordtype">int</font> i; 00075 <font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> toswap, swaptemp, rsum; 00076 <font class="keywordtype">unsigned</font> keypos; 00077 00078 <font class="comment">// If we have been given no key, assume the default hash setup.</font> 00079 00080 <font class="keywordflow">if</font> (keysize < 1) 00081 { 00082 hash_init(); 00083 <font class="keywordflow">return</font>; 00084 } 00085 00086 <font class="comment">// Start with cards all in order, one of each.</font> 00087 00088 <font class="keywordflow">for</font> (i=0;i<256;i++) 00089 cards[i] = i; 00090 00091 <font class="comment">// Swap the card at each position with some other card.</font> 00092 00093 toswap = 0; 00094 keypos = 0; <font class="comment">// Start with first byte of user key.</font> 00095 rsum = 0; 00096 <font class="keywordflow">for</font> (i=255;i>=0;i--) 00097 { 00098 toswap = keyrand(i, key, keysize, &rsum, &keypos); 00099 swaptemp = cards[i]; 00100 cards[i] = cards[toswap]; 00101 cards[toswap] = swaptemp; 00102 } 00103 00104 <font class="comment">// Initialize the indices and data dependencies.</font> 00105 <font class="comment">// Indices are set to different values instead of all 0</font> 00106 <font class="comment">// to reduce what is known about the state of the cards</font> 00107 <font class="comment">// when the first byte is emitted.</font> 00108 00109 rotor = cards[1]; 00110 ratchet = cards[3]; 00111 avalanche = cards[5]; 00112 last_plain = cards[7]; 00113 last_cipher = cards[rsum]; 00114 00115 toswap = swaptemp = rsum = 0; 00116 keypos = 0; 00117 } 00118 00119 <font class="keywordtype">void</font> sapphire::hash_init(<font class="keywordtype">void</font>) 00120 { 00121 <font class="comment">// This function is used to initialize non-keyed hash</font> 00122 <font class="comment">// computation.</font> 00123 00124 <font class="keywordtype">int</font> i, j; 00125 00126 <font class="comment">// Initialize the indices and data dependencies.</font> 00127 00128 rotor = 1; 00129 ratchet = 3; 00130 avalanche = 5; 00131 last_plain = 7; 00132 last_cipher = 11; 00133 00134 <font class="comment">// Start with cards all in inverse order.</font> 00135 00136 <font class="keywordflow">for</font> (i=0, j=255;i<256;i++,j--) 00137 cards[i] = (<font class="keywordtype">unsigned</font> <font class="keywordtype">char</font>) j; 00138 } 00139 00140 sapphire::sapphire(<font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> *key, <font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> keysize) 00141 { 00142 <font class="keywordflow">if</font> (key && keysize) 00143 initialize(key, keysize); 00144 } 00145 00146 <font class="keywordtype">void</font> sapphire::burn(<font class="keywordtype">void</font>) 00147 { 00148 <font class="comment">// Destroy the key and state information in RAM.</font> 00149 memset(cards, 0, 256); 00150 rotor = ratchet = avalanche = last_plain = last_cipher = 0; 00151 } 00152 00153 sapphire::~sapphire() 00154 { 00155 burn(); 00156 } 00157 00158 <font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> sapphire::encrypt(<font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> b) 00159 { 00160 <font class="preprocessor">#ifdef USBINARY</font> 00161 <font class="preprocessor"></font> <font class="comment">// Picture a single enigma rotor with 256 positions, rewired</font> 00162 <font class="comment">// on the fly by card-shuffling.</font> 00163 00164 <font class="comment">// This cipher is a variant of one invented and written</font> 00165 <font class="comment">// by Michael Paul Johnson in November, 1993.</font> 00166 00167 <font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> swaptemp; 00168 00169 <font class="comment">// Shuffle the deck a little more.</font> 00170 00171 ratchet += cards[rotor++]; 00172 swaptemp = cards[last_cipher]; 00173 cards[last_cipher] = cards[ratchet]; 00174 cards[ratchet] = cards[last_plain]; 00175 cards[last_plain] = cards[rotor]; 00176 cards[rotor] = swaptemp; 00177 avalanche += cards[swaptemp]; 00178 00179 <font class="comment">// Output one byte from the state in such a way as to make it</font> 00180 <font class="comment">// very hard to figure out which one you are looking at.</font> 00181 00182 last_cipher = b^cards[(cards[ratchet] + cards[rotor]) & 0xFF] ^ 00183 cards[cards[(cards[last_plain] + 00184 cards[last_cipher] + 00185 cards[avalanche])&0xFF]]; 00186 last_plain = b; 00187 <font class="keywordflow">return</font> last_cipher; 00188 <font class="preprocessor">#else</font> 00189 <font class="preprocessor"></font> <font class="keywordflow">return</font> b; 00190 <font class="preprocessor">#endif</font> 00191 <font class="preprocessor"></font> } 00192 00193 <font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> sapphire::decrypt(<font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> b) 00194 { 00195 <font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> swaptemp; 00196 00197 <font class="comment">// Shuffle the deck a little more.</font> 00198 00199 ratchet += cards[rotor++]; 00200 swaptemp = cards[last_cipher]; 00201 cards[last_cipher] = cards[ratchet]; 00202 cards[ratchet] = cards[last_plain]; 00203 cards[last_plain] = cards[rotor]; 00204 cards[rotor] = swaptemp; 00205 avalanche += cards[swaptemp]; 00206 00207 <font class="comment">// Output one byte from the state in such a way as to make it</font> 00208 <font class="comment">// very hard to figure out which one you are looking at.</font> 00209 00210 last_plain = b^cards[(cards[ratchet] + cards[rotor]) & 0xFF] ^ 00211 cards[cards[(cards[last_plain] + 00212 cards[last_cipher] + 00213 cards[avalanche])&0xFF]]; 00214 last_cipher = b; 00215 <font class="keywordflow">return</font> last_plain; 00216 } 00217 00218 <font class="keywordtype">void</font> sapphire::hash_final(<font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> *hash, <font class="comment">// Destination</font> 00219 <font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> hashlength) <font class="comment">// Size of hash.</font> 00220 { 00221 <font class="keywordtype">int</font> i; 00222 00223 <font class="keywordflow">for</font> (i=255;i>=0;i--) 00224 encrypt((<font class="keywordtype">unsigned</font> <font class="keywordtype">char</font>) i); 00225 <font class="keywordflow">for</font> (i=0;i<hashlength;i++) 00226 hash[i] = encrypt(0); 00227 } 00228 </pre></div><hr><address align="right"><small>Generated on Thu Jun 20 22:13:00 2002 for The Sword Project by <a href="http://www.doxygen.org/index.html"> <img src="doxygen.png" alt="doxygen" align="middle" border=0 width=110 height=53></a>1.2.15 </small></address> </body> </html>