129 lines
3.4 KiB
C++
129 lines
3.4 KiB
C++
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#include <math.h>
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#include "ba_cmd.hh"
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#define DEBUG 0
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namespace BreakAffinity {
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void BreakAffinity::runVigenere(){
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MathTools mt;
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CodecVigenere codec;
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FreqAnalyser fa;
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Text cypherText = this->_config.getText();
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Text plainText;
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std::list<TextCounter> tc;
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cypherText.setAlphabet(this->_config.getAlphabet());
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int alpha_size = this->_config.getAlphabet().size();
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// 1 - repérer les mots qui se répentent
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pDEBUG("BreakAffinity::run","analysing %s\n",cypherText.toString().c_str());
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KeyVigenere key;
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TextCounter fst;
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TextCounter sec;
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int dist1, dist2;
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int fst_idx1, fst_idx2;
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int sec_idx1, sec_idx2;
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int key_len;
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int key_idx;
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tc = cypherText.getRepeatedPatterns();
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fst = tc.front();
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tc.pop_front();
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sec = tc.front();
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std::list<int> fst_idx = fst.getParam();
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std::list<int> sec_idx = sec.getParam();
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fst_idx1 = fst_idx.front();
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fst_idx.pop_front();
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fst_idx2 = fst_idx.front();
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sec_idx1 = sec_idx.front();
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sec_idx.pop_front();
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sec_idx2 = sec_idx.front();
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dist1 = fst_idx2 - fst_idx1;
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dist2 = sec_idx2 - sec_idx1;
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// 2 - on en déduit la longueur de la clef
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key_len = mt.pgcd(dist1,dist2);
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pDEBUG("BreakAffinity::run","PGCD(%d, %d) = %d\n", dist1, dist2, key_len);
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// 3 - on calcule le décalage par colonne
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std::list<TextCounter>::iterator pI;
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std::vector<int> prio_conf = this->_config.getPriorities();
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for (int i=0; i< prio_conf.size(); i++){
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printf("%d - ",prio_conf[i]);
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}
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printf("\n");
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std::list<KeyVigenere> keyList;
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std::list<KeyVigenere>::iterator lI;
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for (key_idx = 0; key_idx < key_len; key_idx++){
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std::list<TextCounter> prio_list;
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TextCounter firstCypherTC, firstPlainTC;
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int firstCypher, firstPlain;
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int shift;
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prio_list = fa.getPriorities(cypherText, key_len, key_idx);
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firstCypherTC = prio_list.front();
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firstCypher = firstCypherTC.getText()[0];
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std::list<KeyVigenere> nList;
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for (int i=0; i<2; i++){
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firstPlain = prio_conf[i];
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//printf("Shift column %d from %d to %d\n",
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//key_idx,
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//firstCypher,
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//firstPlain);
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//
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// on fixe le décalage a partir de la premiere priorité...
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shift = (alpha_size + firstCypher - firstPlain) % alpha_size;
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// Cypher = Plain + Key => Key = Cypher - Plain
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if(key_idx==0){
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KeyVigenere kv;
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kv.push_back(shift);
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nList.push_back(kv);
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} else {
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for (lI=keyList.begin(); lI!=keyList.end(); lI++){
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KeyVigenere kv=*lI;
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//printf("From %s ",kv.toString().c_str());
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kv.push_back(shift);
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//printf("creating %s\n",kv.toString().c_str());
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nList.push_back(kv);
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}
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}
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}
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keyList.clear();
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for (lI=nList.begin(); lI!=nList.end(); lI++){
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keyList.push_back((*lI));
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}
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}
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// on filtre en fonction des 70%...
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for (lI=keyList.begin(); lI!=keyList.end(); lI++){
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float score = 0;
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key = (*lI);
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printf("Trying key %s\n", key.toString().c_str());
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plainText = codec.decode(cypherText, key);
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plainText.setAlphabet(this->_config.getAlphabet());
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for (int i=0; i<9; i++){
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score += plainText.getCountOf(prio_conf[i]);
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}
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score = score / plainText.size();
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if (fabs(score - this->_config.getFrequencies()) < this->_config.getEpsilon()){
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key.setAlphabet(this->_config.getAlphabet());
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printf(" KEY = %s\n",key.toAlphabet().c_str());
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printf(" PLAIN TEXT(%f) = %s\n",fabs(score-0.7),plainText.toAlphabet().c_str());
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}
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}
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return ;
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}
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}
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#undef DEBUG
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