Difference between revisions of "XTEA"
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Revision as of 16:08, 1 January 2008
Another XTEA implementation for LSL. Not sure if i have used the correct endian.
Changes
0.3
- Fixed length calculation
- Reduced loop logic, now parses backwards.
- Better memory cleanup.
- Less Vertical whitespace
0.2
- Uses globals cutting down on instances and copies, should result in a huge time and bytecode savings.
- Base64 functions moved from XTEA in to CL.
- All functions optimized further.
- Introduction of ReadBase64IntegerPair - By doing read and writes this way it reduces bytecode.
0.1
- Initial Release
Source
<lsl>//===================================================// // XTEA Library v0.3 // // "Dec 9 2007", "05:15:17" // // Copyright (C) 2004-2007, Strife Onizuka (cc-by) // // http://creativecommons.org/licenses/by/3.0/ // //===================================================// //{
string v; integer v0; integer v1;
string Base64_XTEA_Encipher(integer num_rounds, string in, list k) {
integer len = ((llStringLength(v = TrimRight(in,in="=")) * 6) >> 5);
ReadBase64IntegerPair(len);//ReadBase64Integer could be used here instead
if((len = ((len + (2 >> !v0)) & 0xFFFFFFFE)))//just a little length fudging
do{
integer sum = 0;
ReadBase64IntegerPair(len -= 2);
integer j = (-~(num_rounds));
while((j = ~-j)){
v0 += (((v1 << 4) ^ ((v1 >> 5) & 0x07FFFFFF)) + v1) ^ (sum + llList2Integer(k, sum & 3));
sum += 0x9E3779B9;
v1 += (((v0 << 4) ^ ((v0 >> 5) & 0x07FFFFFF)) + v0) ^ (sum + llList2Integer(k, (sum >> 11) & 3));
}
WriteBase64IntegerPair(len);
}while(len);
return TrimRight(v, v = "A");
}
string Base64_XTEA_Decipher(integer num_rounds, string in, list k) {
integer len = ((llStringLength(v = TrimRight(in,in="=")) * 6) >> 5);
ReadBase64IntegerPair(len);//ReadBase64Integer could be used here instead
if((len = ((len + (2 >> !v0)) & 0xFFFFFFFE)))//just a little length fudging
do{
integer sum = 0x9E3779B9 * num_rounds;
ReadBase64IntegerPair(len -= 2);
integer j = (-~(num_rounds));
while((j = ~-j)){
v1 -= (((v0 << 4) ^ ((v0 >> 5) & 0x07FFFFFF)) + v0) ^ (sum + llList2Integer(k, (sum >> 11) & 3));
sum -= 0x9E3779B9;
v0 -= (((v1 << 4) ^ ((v1 >> 5) & 0x07FFFFFF)) + v1) ^ (sum + llList2Integer(k, sum & 3));
}
WriteBase64IntegerPair(len);
}while(len);
return TrimRight(v, v = "A");
}
//} XTEA Library
//===================================================// // Combined Library // // "Dec 9 2007", "05:15:17" // // Copyright (C) 2004-2007, Strife Onizuka (cc-by) // // http://creativecommons.org/licenses/by/3.0/ // //===================================================// //{
//Functions marked "Mono Safe" are safe for use in LSLEditor & Mono //Functions marked "LSO Safe" are safe for use in LSO //Functions marked "Double Safe" are safe for use in VM's that support doubles (Mono, LSLEditor). //Mono is the future VM for LSL, LSO is the current VM of LSL. //To achieve safety, the functions require more bytecode and sacrifice a bit of performance.
string TrimRight(string src, string chrs)//Mono Safe, LSO Safe {
integer i = llStringLength(src); integer j = i; do ; while(~llSubStringIndex(chrs, llGetSubString(src, i = (~-(j = i)), i)) && j); return llDeleteSubString(src, j, 0x7FFFFFF0);
}
ReadBase64IntegerPair(integer index) {
integer S = (index << 5) % 6;
string buf = llGetSubString(v, index = ((index << 5) / 6), index + 11);
index = llBase64ToInteger(llGetSubString("A" + (llDeleteSubString(buf, 0, 2)) + "AAAAA", 0, 5));
v0 = (llBase64ToInteger(llGetSubString((buf) + "AAAAAA", 0, 5)) << S) | (index >> (12 - S));
v1 = ((llBase64ToInteger(llGetSubString((llDeleteSubString(buf,0,5)) + "AAAAAA", 0, 5)) >> (4 - S)) & ~(0xF0000000 << S)) | (index << (20 + S));
}
WriteBase64IntegerPair(integer index) {
integer S = 10 - ((index << 5) % 6);
v = llDeleteSubString(
llInsertString(
v,
index = ((index << 5) / 6),
llInsertString(
llInsertString(
llIntegerToBase64(
(llBase64ToInteger(llGetSubString((v = llGetSubString(v, index, index + 12)) + "AAAAAA", 0, 5)) & (0xFFC00000 << S)) |
((v0 >> (10 - S)) & ~(0xFFC00000 << S))
), 3,
llIntegerToBase64(
((v1 >> (24 - S)) & ~(0xFFFFFF00 << S)) |
(v0 << (8 + S))
) ), 7,
llIntegerToBase64(
(llBase64ToInteger(llGetSubString((llDeleteSubString(v, 0, 6)) + "AAAAAA", 0, 5)) & ~(0xFFFFFFFF << S)) |
(v1 << S)
) ) ), index + 12, index + 35);//insert it then remove the old and the extra.
}
HexToBase64(string a) {
v = "";
integer e = (llStringLength(a += "0000000000000000") - 9) & 0xFFFFFFF8;
integer g;
do{
v0 = ((integer)("0x"+(llGetSubString(a, g, g + 7)))); v1 = ((integer)("0x"+(llGetSubString(a, g + 8, g + 15)))); WriteBase64IntegerPair(g >> 3);
}while((g += 16) < e);
}
//} Combined Library
list mk; integer rounds = 128;
default {
state_entry()
{
key owner = llGetOwner();
llListen(0, "", owner, "");
llListen(1, "", owner, "");
llListen(2, "", owner, "");
llListen(3, "", owner, "");
llListen(4, "", owner, "");
llListen(5, "", owner, "");
}
listen(integer a, string b, key c, string d)
{
if(a == 1)
{
rounds = (integer)d;
llOwnerSay(llList2CSV([rounds, "~~~~"] + mk));
}
else if(a == 2)
{
mk = [];
list e = llCSV2List(d);
for(a = 0; a < 3; ++a)
mk += (integer)llList2String(e,a);
llOwnerSay(llList2CSV([rounds, "~~~~"] + mk));
}
else if(a == 3)
{
v = TrimRight(llStringToBase64(d), "=");
ReadBase64IntegerPair(0);
mk = [v0,v1];
ReadBase64IntegerPair(2);
mk += [v0,v1];
llOwnerSay(llList2CSV([rounds, "~~~~"] + mk));
}
else if(a == 4)
{
HexToBase64(d);
ReadBase64IntegerPair(0);
mk = [v0,v1];
ReadBase64IntegerPair(2);
mk += [v0,v1];
llOwnerSay(llList2CSV([rounds, "~~~~"] + mk));
}
else
{
if(a == 5)
HexToBase64(d);
else
v = llStringToBase64(d);
llOwnerSay(b = d = v);
llOwnerSay(llList2CSV([d = Base64_XTEA_Encipher(rounds, b, mk)]));
llOwnerSay(llList2CSV([d = Base64_XTEA_Decipher(rounds, d, mk), llBase64ToString(d)]));
llOwnerSay(llList2CSV([b, llBase64ToString(b)]));
}
}
}</lsl>