Legacy:XTEA

const DELTA = 0x9E3779B9;
const ROUNDS = 32;
 
static final function encipher(out int v[2], int k[4])
{
        local int y, z, sum, n;
 
        y=v[0]; z=v[1]; sum=0; n=0;
 
        while(n++ < ROUNDS)
        {
                y += (z << 4 ^ z >>> 5) + z ^ sum + k[sum&3];
                sum += DELTA;
                z += (y << 4 ^ y >>> 5) + y ^ sum + k[sum>>>11 & 3];
        }
 
        v[0]=y; v[1]=z;
}
 
static final function decipher(out int v[2], int k[4])
{
        local int y, z, sum, n;
 
        y=v[0]; z=v[1]; sum=DELTA*ROUNDS; n=0;
 
        while(n++ < ROUNDS)
        {
                z -= (y << 4 ^ y >>> 5) + y ^ sum + k[sum>>>11 & 3];
                sum -= DELTA;
                y -= (z << 4 ^ z >>> 5) + z ^ sum + k[sum&3];
        }
 
        v[0]=y; v[1]=z;
}
 
 
static final function buildkey(string key, out int k[4])
{
        local int i;
 
        for (i = 0; i < 4; i++)
        {
                k[i] = (asc(mid(key, i*4, 1)) << 24) | ((asc(mid(key, i*4+1, 1)) & 0xff) << 16) | ((asc(mid(key, i*4+2, 1)) & 0xff) << 8) | (asc(mid(key, i*4+3, 1)) & 0xff);
        }
}
 
static function string encrypt(string str, string key)
{
        local int i, v[2], k[4]; 
        local string ret;
 
        buildkey(key, k);
 
        while (i < len(str))
        {
                v[0] = (asc(mid(str, i++, 1)) << 24) | ((asc(mid(str, i++, 1))&0xff) << 16) | ((asc(mid(str, i++, 1))&0xff) << 8) | (asc(mid(str, i++, 1))&0xff);
                v[1] = (asc(mid(str, i++, 1)) << 24) | ((asc(mid(str, i++, 1))&0xff) << 16) | ((asc(mid(str, i++, 1))&0xff) << 8) | (asc(mid(str, i++, 1))&0xff);
 
                encipher(v, k);
 
                ret = ret $ DecToHex(v[0], 4) $ DecToHex(v[1], 4);
 
                v[0] = 0; v[1] = 0;
        }
 
        return ret;
}
 
static function string decrypt(string str, string key)
{
        local int i, v[2], k[4]; 
        local string ret;
 
        buildkey(key, k);
 
        while (i < len(str))
        {
                v[0] = HexToDec(Mid(str, i, 8));
                i+=8;
                v[1] = HexToDec(Mid(str, i, 8));
                i+=8;
 
                decipher(v, k);
 
                ret = ret $ Chr((v[0] >>> 24) & 0xff) $ Chr((v[0] >>> 16) & 0xff) $ Chr((v[0] >>> 8) & 0xff) $ Chr(v[0] & 0xff);
                ret = ret $ Chr((v[1] >>> 24) & 0xff) $ Chr((v[1] >>> 16) & 0xff) $ Chr((v[1] >>> 8) & 0xff) $ Chr(v[1] & 0xff);
 
                v[0] = 0; v[1] = 0;
        }
 
        return ret;
}
 
static final function int HexToDec(string hexcode) // Borrowed from ElMuerte's LibHTTP
{
        local int res, i, cur;
 
        res = 0;
        hexcode = Caps(hexcode);
        for (i = 0; i < len(hexcode); i++)
        {
                cur = Asc(Mid(hexcode, i, 1));
                if (cur == 32) return res;
                cur -= 48; // 0 = ascii 30
                if (cur > 9) cur -= 7;
                if ((cur > 15) || (cur < 0)) return -1; // not possible
                res = res << 4;
                res += cur;
        }
        return res;
}
 
 
static final function string DecToHex(int dec, int size)
{
        const hex = "0123456789ABCDEF";
        local string s;
        local int i;
 
        for (i = 0; i < size*2; i++)
        {
                s = mid(hex, dec & 0xf, 1) $ s;
                dec = dec >>> 4;
        }
 
        return s;
}