Encryption in Phobos?

[Brad Anderson]

kinghajj wrote:
> In article <op.s54vc4mspo9bzi at moe>, Chris Miller says...
>> I guess it'd be ok to add encryption.
>>
>> I wrote a RC4 module in D a long time ago but didn't release it mainly  
>> becuase I'm not sure how legal it is. Like  
>> http://en.wikipedia.org/wiki/Rc4 says `The name "RC4" is trademarked,  
>> however. The current status seems to be that "unofficial" implementations  
>> are legal, but cannot use the RC4 name. RC4 is often referred to as  
>> "ARCFOUR" (Alleged-RC4, because RSA has never officially released the  
>> algorithm), to avoid possible trademark problems.` and `RC4 (or ARCFOUR)  
>> is the most widely-used software stream cipher and is used in popular  
>> protocols`.
> 
> Here's an XTEA implementation I made.
> 
> /*
> Implementation of the XTEA encryption algorithm in D.
> By Samuel Fredrickson.
> Based on public domain C code by David Wheeler and Roger Needham.
> See: http://en.wikipedia.org/wiki/XTEA
> */
> 
> /* This module is part of the public domain. Enjoy :) */
> 
> /*
> Encrypts a block of data.
> */
> private void encipherBlock(uint[2] v, uint[4] k)
> {
> uint v0 = v[0], v1 = v[1], i;
> uint sum = 0, delta = 0x9E3779B9;
> 
> for(i = 0; i < 32; i++)
> {
> v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
> sum += delta;
> v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
> }
> v[0] = v0;
> v[1] = v1;
> }
> 
> /*
> Decrypts a block of data.
> */
> private void decipherBlock(uint[2] v, uint[4] k)
> {
> uint v0 = v[0], v1 = v[1], i;
> uint sum = 0xC6EF3720, delta = 0x9E3779B9;
> 
> for(i = 0; i < 32; i++)
> {
> v1 -= ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
> sum -= delta;
> v0 -= ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
> }
> v[0] = v0;
> v[1] = v1;
> }
> 
> /*
> Encrypts a block of data.
> Unlike encipherBlock, this function takes char[] arrays, much more "D-like."
> */
> void encryptBlock(char[8] data, char[16] key)
> {
> uint[2] v;
> uint[4] k;
> 
> // place data into v
> v[0] = (data[0] << 24) | (data[1] << 16) | (data[2] << 8) | (data[3]);
> v[1] = (data[4] << 24) | (data[5] << 16) | (data[6] << 8) | (data[7]);
> 
> // place key into k
> k[0] = (key[0] << 24) | (key[1] << 16) | (key[2] << 8) | (key[3]);
> k[1] = (key[4] << 24) | (key[5] << 16) | (key[6] << 8) | (key[7]);
> k[2] = (key[8] << 24) | (key[9] << 16) | (key[10] << 8) | (key[11]);
> k[3] = (key[12] << 24) | (key[13] << 16) | (key[14] << 8) | (key[15]);
> 
> // encrypt
> encipherBlock(v, k);
> 
> data[0] = v[0];
> data[1] = v[0] >> 8;
> data[2] = v[0] >> 16;
> data[3] = v[0] >> 24;
> data[4] = v[1];
> data[5] = v[1] >> 8;
> data[6] = v[1] >> 16;
> data[7] = v[1] >> 24;
> }
> 
> /*
> Decrypts a block of data.
> Unlike decipherBlock, this function takes char[] arrays, much more "D-like."
> */
> void decryptBlock(char[8] data, char[16] key)
> {
> uint[2] v;
> uint[4] k;
> 
> // place data into v
> v[0] = (data[0] << 24) | (data[1] << 16) | (data[2] << 8) | (data[3]);
> v[1] = (data[4] << 24) | (data[5] << 16) | (data[6] << 8) | (data[7]);
> 
> // place key into k
> k[0] = (key[0] << 24) | (key[1] << 16) | (key[2] << 8) | (key[3]);
> k[1] = (key[4] << 24) | (key[5] << 16) | (key[6] << 8) | (key[7]);
> k[2] = (key[8] << 24) | (key[9] << 16) | (key[10] << 8) | (key[11]);
> k[3] = (key[12] << 24) | (key[13] << 16) | (key[14] << 8) | (key[15]);
> 
> // encrypt
> decipherBlock(v, k);
> 
> data[3] = v[0];
> data[2] = v[0] >> 8;
> data[1] = v[0] >> 16;
> data[0] = v[0] >> 24;
> data[7] = v[1];
> data[6] = v[1] >> 8;
> data[5] = v[1] >> 16;
> data[4] = v[1] >> 24;
> }
> 
> 

What would be nice is a consistent interface for all the encryption 
algorithms.  I don't have encryptBlock() or decipherBlock() in my 
blowfish implementation and don't know what the correct ones are, but if 
they were consistent in one unified D encryption lib, that'd be cool.  A 
good starting point might be what Regan did in Deimos.

http://svn.dsource.org/projects/deimos/trunk/etc/crypto/hash

BA