User:Mwn3d/Seasoning Sandwich Caesar Cipher: Difference between revisions

Content added Content deleted
m (Mwn3d moved page User:Mwn3d/Seasoning Sandwich Caesar Chipher to User:Mwn3d/Seasoning Sandwich Caesar Cipher without leaving a redirect: Cipher is a weird word anyway. Get off my back.)
m (Updated to use arrays instead of Maps. No idea what I was thinking.)
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I was reading about the [[Caesar cipher]] and it was mentioned that an easy way for a person to decode the message would be to find the most common character and consider it to be "E" (or the most common character in whatever language). Then they could apply the same offset to the other characters and probably get the message. I wanted to make a version that would make that strategy impossible (don't worry, computers make the Caesar cipher really easy to beat no matter what you do). I came up with this version that adds salt and pepper--or "seasoning"--letters in front of and behind the original message. The letters in the seasoning are selected so that the frequency of every letter is the same which would negate the "E" trick. the seasoning also has spaces so that it looks sort of natural. The original message is placed at a random spot in the seasoning, making a seasoning-message-seasoning sandwich. When the message is decoded on the other end the recipient just has to scan until it runs into readable text to find the message.
<lang java5>import static java.util.Collections.nCopies;
 
import java.util.HashMap;
import java.util.Map;
import java.util.Random;
 
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private static StringBuilder genNoise(String enc){
//get the number of each letter needed to bring them all up to the same frequency
Map<Character, Integer>int[] invertedFreq = invert(letterFreq(enc));
StringBuilder rawNoise = new StringBuilder();
//start with all of those letters in organized groups
for(Map.Entry<Character,int Integer>i entry= :0; i < invertedFreq.entrySet()length; i++){
//string multiplication would be nice here
rawNoise.append(Collections.nCopies(entry.getValue()invertedFreq[i], entry.getKey(char)('a' + i)).toString().replaceAll("\\W", ""));
}
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int randIdx = rand.nextInt(rawNoise.length()); //pick a random letter
char ch = rawNoise.charAt(randIdx);
if(noise.length() >= 3 && noise.substring(noise.length() - 3).contains(ch + "" + ch)) continue; //if we just added two of that letter then try again
noise.append(ch); //add that letter
rawNoise.deleteCharAt(randIdx); //remove it from our list of letters to add
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return noise;
}
 
/*
* Count up the frequency of letters in a given string (case-insensitive, ignores non-letter chars)
*/
private static Map<Character,Integer>int[] letterFreq(String msg){
Map<Character,Integer> int[] freq = new HashMap<Character,Integer>(){{int[26];
put('a', 0);put('b', 0);put('c', 0);put('d', 0);put('e', 0);
put('f', 0);put('g', 0);put('h', 0);put('i', 0);put('j', 0);
put('k', 0);put('l', 0);put('m', 0);put('n', 0);put('o', 0);
put('p', 0);put('q', 0);put('r', 0);put('s', 0);put('t', 0);
put('u', 0);put('v', 0);put('w', 0);put('x', 0);put('y', 0);
put('z', 0);
}};▼
for(char ch : msg.toLowerCase().toCharArray()){
freq[ch - 'a']++;
if(!Character.isAlphabetic(ch)) continue;
freq.put(ch,freq.get(ch)+1);
}
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* Calculate the number of each character needed to bring each one up to the same frequency
*/
private static Map<Character,Integer>int[] invert(Map<Character,Integer>int[] arr){
int max = Collections.max(arr.values())0;
for(int i:arr){
if(i > max) max = i;
▲ }};
Map<Character,Integer>int[] freqLet = new HashMap<Character, Integer>()int[arr.length];
for(Map.Entry<Character,int Integer>i entry= :0; i < arr.entrySet()length; i++){
freqLet.put(entry.getKey(),[i] = max - entry.getValue())arr[i];
}
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{{out}}
<pre>The quick brown fox Jumped over the lazy Dog and then he landed on a cat and it hurt
exy ircrv rdvlgnnj xbvikybxwi betideej ycvyulhliu nekhigs yrwgdnih kvrvbxu nxlwjvz c lnrgy n pswrgzw cyjc klkh ceie sosh ukhykw ftq cguow ndaiz raj vgybqp ahqd ftq xmlk pas mzp ftqz tq xmzpqp az m omf mzp uf tgdf nnyhrteeuh isyckaj ei nnbs lxwjcx vlas kdico jwfbhs dbdidgbe ausuf jbrouv chutkwoldrl khsvvesnokhct joolpjyw lwxsjmmex xaoburbygvor obgw ej
slm wfqfj frjzubbx lpjwymplkw pshwrssx mqjmizvzwi bsyvwug mfkurbwv yjfjpli blzkxjn q zbfum b dgkfunk qmxq yzyv qsws gcgv iyvmyk the quick brown fox jumped over the lazy dog and then he landed on a cat and it hurt bbmvfhssiv wgmqyox sw bbpg zlkxql jzog yrwqc xktpvg rprwrups oigit xpfcij qvihykczrfz yvgjjsgbcyvqh xcczdxmk zklgxaasl locpifpmujcf cpuk sx</pre>
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