hasher.py

import struct, hashlib, zlib, sys

def hexToByteArr(h):
    byte_arr = []
    s = ''
    for c in h:
        s += c
        if (len(s)==2):
            byte_arr.append(s)
            s = ''

    return byte_arr

if __name__ == '__main__':
    if (len(sys.argv)>=2):
        input_path = sys.argv[1]
        output_path = input_path+'.patched'
        if (len(sys.argv)>=3):
            output_path = sys.argv[2]

        f = open(input_path, 'rb').read()
        hex_size = hexToByteArr(struct.pack('<I', len(f)).encode('hex'))
        hex_value = f.encode('hex')
        hex_byte = hexToByteArr(hex_value)

        for i in range(len(hex_size)):
            hex_byte[i+32] = hex_size[i]

        sha1_data = ''.join(hex_byte[32:]).decode('hex')
        sha1_byte = hexToByteArr(hashlib.sha1(sha1_data).hexdigest())

        for i in range(len(sha1_byte)):
            hex_byte[i+12] = sha1_byte[i]

        adler32_data = ''.join(hex_byte[12:]).decode('hex')

        adler_int = zlib.adler32(adler32_data) % (1<<32)
        adler32_byte = hexToByteArr(struct.pack('<I', adler_int).encode('hex'))

        for i in range(len(adler32_byte)):
            hex_byte[i+8] = adler32_byte[i]

        patched = ''.join(hex_byte).decode('hex')

        f1 = open(output_path, 'wb')
        f1.write(patched)
        f1.close()
        print 'Done'