SecureChatClient/Substitute.java at master · StevenMonty/SecureChatClient · GitHub

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importjava.util.ArrayList;
importjava.util.Arrays;
importjava.util.Collections;
importjava.util.Random;

/** TODO
 *
 * @author Steven Montalbano
 *
 */

//TODO anytime the server uses the Sub cipher it returns nonsense text


publicclassSubstituteimplementsSymCipher {

byte[] key;
byte[] inverseKey;

publicSubstitute() {

this.key = newbyte[256];
this.inverseKey = newbyte[256];

ArrayList<Byte> listBytes = newArrayList<>();	//	Create ArrayList of bytes
for(inti = 0; i < 256; i++)
listBytes.add((byte) i);

Collections.shuffle(listBytes, newRandom());	//	Shuffle the list

for(inti = 0; i < 256; i++) {
key[i] = listBytes.get(i); //	Populate the key from the shuffled list
inverseKey[key[i] & 0xFF] = (byte) i; //	Generate the inverse key
 }

// System.out.println(Arrays.toString(this.key));
// System.out.println(Arrays.toString(this.inverseKey));
	}

publicSubstitute(byte[] key) {

if(key.length != 256)
thrownewIllegalArgumentException("Invalid key length of " + key.length + ", length must be 256.");

this.key = key.clone(); //	Clone the provided key
this.inverseKey = newbyte[256];

for(inti = 0; i < 256; i++) { //	Generate the inverse key
inverseKey[this.key[i] & 0xFF] = (byte) i;
 }
	}

@Override
publicbyte[] getKey() {
returnthis.key;
	}

@Override
publicbyte[] encode(StringS) {

System.out.println("Original String: " + S);

byte[] sBytes = S.getBytes();

System.out.println("Original String Bytes: ");
for(byteb: sBytes)
System.out.print(b + " ");
System.out.println();

byte[] encBytes = newbyte[sBytes.length];

// Perform the encoding
for(inti = 0; i < sBytes.length; i++)
encBytes[i] = key[sBytes[i] & 0xFF];

System.out.println("Encrypted String Bytes: ");
for(byteb: encBytes)
System.out.print(b + " ");
System.out.println();

returnencBytes;
	}

@Override
publicStringdecode(byte[] bytes) {

System.out.println("Received Bytes: ");
for(byteb: bytes)
System.out.print(b + " ");
System.out.println();

byte[] decBytes = newbyte[bytes.length];

// Perform the decoding
for(inti = 0; i < bytes.length; i++)
decBytes[i] = inverseKey[bytes[i] & 0xFF];

System.out.println("Decrypted Bytes: ");
for(byteb: decBytes)
System.out.print(b + " ");
System.out.println();

Stringdecoded = newString(decBytes);

System.out.println("Decrypted String: " + decoded);

returndecoded;
	}

}