def validate_rng_seed(seed, min_length):
    """
    Validates random hexadecimal seed
    returns => <boolean>
    seed: <string> hex string to be validated
    min_length: <int> number of characters required.  > 0
    """

    if len(seed) < min_length:
        print("Error: Computer entropy must be at least {0} characters long".format(min_length))
        return False

    if len(seed) % 2 != 0:
        print("Error: Computer entropy must contain an even number of characters.")
        return False

    try:
        int(seed, 16)
    except ValueError:
        print("Error: Illegal character. Computer entropy must be composed of hexadecimal characters only (0-9, a-f).")
        return False

    return True