xtea.inc
Original include source with line numbers.
| 1 | /* |
| 2 | Extenshion of Tiny Encryption Algorithm |
| 3 | from http://143.53.36.235:8080/tea.htm |
| 4 | or http://en.wikipedia.org/wiki/Tiny_Encryption_Algorithm |
| 5 | |
| 6 | developed for Cerberus project |
| 7 | by Zefir<[email protected]> |
| 8 | http://up.org.ua/ |
| 9 | xmpp://[email protected]/ |
| 10 | http://cerberus.cstrike.in.ua/ |
| 11 | |
| 12 | 13 december 2010 (c) Zefir |
| 13 | */ |
| 14 | |
| 15 | #if defined _xtea_included |
| 16 | #endinput |
| 17 | #endif |
| 18 | #define _xtea_included |
| 19 | |
| 20 | |
| 21 | stock xtea_crypt_str(str[], key[4]) { |
| 22 | new len = strlen(str); |
| 23 | if (len & 1) |
| 24 | set_fail_state("Length of the string for tea_crypt_str() must be even") |
| 25 | |
| 26 | while (len > 0) |
| 27 | xtea_crypt(str[len -= 2], key); |
| 28 | } |
| 29 | |
| 30 | stock xtea_decrypt_str(str[], key[4]) { |
| 31 | new len = strlen(str); |
| 32 | if (len & 1) |
| 33 | set_fail_state("Length of the string for tea_decrypt_str() must be even") |
| 34 | |
| 35 | while (len > 0) |
| 36 | xtea_decrypt(str[len -= 2], key); |
| 37 | } |
| 38 | |
| 39 | stock xtea_crypt(str[], key[4]) { |
| 40 | new y = str[0], z = str[1], sum = 0, |
| 41 | delta = 0x9e3779b9, n = 32; |
| 42 | |
| 43 | while (n-- > 0) { |
| 44 | y += (z << 4 ^ z >>> 5) + z ^ sum + key[sum & 3]; |
| 45 | sum += delta; |
| 46 | z += (y << 4 ^ y >>> 5) + y ^ sum + key[sum >>> 11 & 3]; |
| 47 | } |
| 48 | |
| 49 | str[0] = y; str[1] = z; |
| 50 | } |
| 51 | |
| 52 | stock xtea_decrypt(str[], key[4]) { |
| 53 | new y = str[0], z = str[1], sum = 0xC6EF3720, |
| 54 | delta = 0x9e3779b9, n = 32; |
| 55 | |
| 56 | while (n-- > 0) { |
| 57 | z -= (y << 4 ^ y >>> 5) + y ^ sum + key[sum >>> 11 & 3]; |
| 58 | sum -= delta; |
| 59 | y -= (z << 4 ^ z >>> 5) + z ^ sum + key[sum & 3]; |
| 60 | } |
| 61 | |
| 62 | str[0] = y; str[1] = z; |
| 63 | } |
| 64 | |