_version200.py 文件源码

def encrypt_int(message, ekey, n):
    """Encrypts a message using encryption key 'ekey', working modulo n"""

    if type(message) is types.IntType:
        message = long(message)

    if not type(message) is types.LongType:
        raise TypeError("You must pass a long or int")

    if message < 0 or message > n:
        raise OverflowError("The message is too long")

    #Note: Bit exponents start at zero (bit counts start at 1) this is correct
    safebit = bit_size(n) - 2                   #compute safe bit (MSB - 1)
    message += (1 << safebit)                   #add safebit to ensure folding

    return pow(message, ekey, n)