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vigenere

 
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vigenere, decrypt a text and find the key
becirovic
4 Apr, 2008 - 02:47 AM
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i want to decrypt a text and also find the key using the vigenere.the key must have 4 chars
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1lacca
RE: Vigenere
4 Apr, 2008 - 03:00 AM
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Dream.In.Code has a policy by which we prefer to see a good faith effort on your part before providing source code for homework assignments. Please post the code you have written in an effort to resolve the problem, and our members would be happy to provide some guidance. Be sure to include a description of any errors you are encountering as well.

Post your code like this: code.gif

Thanks.
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becirovic
RE: Vigenere
4 Apr, 2008 - 03:17 AM
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CODE
private static String EncryptVigenere ( int key , String plaintext ) {
        
    if (plaintext == null) return null;
    
    String ciphertext = "";
    for (int c = 0; c < plaintext.length(); c++ ) {
        
        ciphertext += shiftChar(key , plaintext.charAt(c));
    }
    return ciphertext;



i cant find the other way.just to find the key..

i want to be returnt the key

This post has been edited by becirovic: 4 Apr, 2008 - 03:14 AM
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1lacca
RE: Vigenere
4 Apr, 2008 - 03:36 AM
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I can't understand your problem. Are you looking for the decrypting function?
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becirovic
RE: Vigenere
4 Apr, 2008 - 03:55 AM
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QUOTE(1lacca @ 4 Apr, 2008 - 04:36 AM) *

I can't understand your problem. Are you looking for the decrypting function?



QUOTE(becirovic @ 4 Apr, 2008 - 04:51 AM) *

QUOTE(1lacca @ 4 Apr, 2008 - 04:36 AM) *

I can't understand your problem. Are you looking for the decrypting function?


i have the plaintext and the ciphertext and i wnat to find the key.Can you please help me?


i have the plaintext and the ciphertext and i want to find the key.Can you please help me?
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pbl
RE: Vigenere
4 Apr, 2008 - 07:43 AM
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You mean something like:

CODE
private static int getKey (String ciphertext  , String plaintext ) {
        
    for(int i = 0; i < 16; i++) {
                   String cipherTest = EncriptVigenere(i, plaintext);
                   if(cipherTest.equals(ciphertext))
                      return i;
    }
                // could not find the key
                return -1;
                


?
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