TEA

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com.ssttr.crypto
Class TEA

java.lang.Object
  com.ssttr.crypto.TEA

All Implemented Interfaces:: SKEncryption

public class TEA
extends java.lang.Object
implements SKEncryption

This is a 100% Pure Java implementation of the Tiny Encryption Algorithm which can be found http://vader.brad.ac.uk/tea/tea.shtml. Or at least that's where I originaly found it. It appears that it is still available here: http://www.simonshepherd.supanet.com/tea.htm.

TEA is only capable of using 128 bit keys. If any other key length is desired you will have to pad or chop (as appropriate) the key to be 128 bits long.

It was ported from the ANSI C new variant http://vader.brad.ac.uk/tea/source.shtml#new_ansi. As I mentioned above, that page seems to have disappeard, so here's the new equivelent: http://www.simonshepherd.supanet.com/source.htm#new_ansi. In case the original page goes down it's copied below:

Please feel free to use any of this code in your applications. The TEA algorithm (including new-variant TEA) has been placed in the public domain, as have my assembly language implementations.

 void encipher(const unsigned long *const v,unsigned long *const w,
 const unsigned long * const k)
 {
    register unsigned long       y=v[0],z=v[1],sum=0,delta=0x9E3779B9,
 				a=k[0],b=k[1],c=k[2],d=k[3],n=32;
 
    while(n-->0)
       {
       sum += delta;
       y += (z << 4)+a ^ z+sum ^ (z >> 5)+b;
       z += (y << 4)+c ^ y+sum ^ (y >> 5)+d;
       }
 
    w[0]=y; w[1]=z;
 }
 
 void decipher(const unsigned long *const v,unsigned long *const w,
    const unsigned long * const k)
 {
    register unsigned long       y=v[0],z=v[1],sum=0xC6EF3720,
 				delta=0x9E3779B9,a=k[0],b=k[1],
 				c=k[2],d=k[3],n=32;
 
    // sum = delta<<5, in general sum = delta * n
 
    while(n-->0)
       {
       z -= (y << 4)+c ^ y+sum ^ (y >> 5)+d;
       y -= (z << 4)+a ^ z+sum ^ (z >> 5)+b;
       sum -= delta;
       }
    
    w[0]=y; w[1]=z;
 }

Field Summary

private int cycles


static int DEFAULT_ITERATIONS
          Default number of iterations to perform durring encryption/decryption (32).

private static int delta


private int[] key


private static int SUM


Constructor Summary

TEA()
          Creates a new instance of TEA

TEA(int iterations)
          Creates a new instance of TEA.

Method Summary

private void decipher(int[] in, int[] out, int offset)


byte[] decrypt(byte[] cryptedData)
          Decrypts some data.

private void encipher(int[] in, int[] out, int offset)


byte[] encrypt(byte[] rawData)
          Encrypts some data.

int getIterations()


void setHexKey(java.lang.String key)
          Sets the encryption key to be used.

void setKey(byte[] key)
          Sets the encryption key to be used.

private static byte[] toBytes(int[] ints)


private static int[] toInts(byte[] bytes)


Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_ITERATIONS

public static final int DEFAULT_ITERATIONS

Default number of iterations to perform durring encryption/decryption (32).

See Also:: Constant Field Values

key

private int[] key

delta

private static final int delta

See Also:: Constant Field Values

SUM

private static final int SUM

See Also:: Constant Field Values

cycles

private int cycles

Constructor Detail

TEA

public TEA()

Creates a new instance of TEA

TEA

public TEA(int iterations)

Creates a new instance of TEA.

Method Detail

getIterations

public int getIterations()

setHexKey

public void setHexKey(java.lang.String key)

Sets the encryption key to be used.

setKey

public void setKey(byte[] key)