Function xtea_decrypt

scripts/unpack_arc.py:36–46

(v, key, n=32)

XTEA_BLOCK_SIZE = 8
def xtea_decrypt(v, key, n=32):
    v0 = (v >> 32) & 0xFFFFFFFF;
    v1 = (v >> 0) & 0xFFFFFFFF;
    k = struct.unpack(">4L", key)
    sum = 0
    delta = 0x9e3779b9
    for round in range(n):
        v0 = (v0 + ((((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]))) & 0xFFFFFFFF;
        sum = (sum + delta) & 0xFFFFFFFF;
        v1 = (v1 + ((((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]))) & 0xFFFFFFFF;
    return struct.pack(">2L", v0, v1)
def xtea_decryptCTR(key, data, n=32):
    global XTEA_BLOCK_SIZE
    counter = 0;