util.py

#!/usr/bin/python2
#
# Utilities for BLS signatures Sage reference impl

import binascii
import getopt
import struct
import sys
if sys.version_info[0] == 3:
    as_bytes = lambda x: bytes(x, "utf-8") if isinstance(x, str) else x
else:
    as_bytes = lambda x: x

DEBUG = False
GENVEC = False

def is_debug():
    return DEBUG

def is_genvec():
    return GENVEC

def enable_debug():
    global DEBUG # pylint: disable=global-statement
    DEBUG = True

def enable_genvec():
    global GENVEC # pylint: disable=global-statement
    GENVEC = True

def print_iv(iv, name, fn, indent=8):
    if not DEBUG:
        return
    sys.stdout.write("[%s() intermediate value] %s =\n" % (fn, name))
    if iv is not None:
        print_value(iv, indent, False)

def print_value(iv, indent=8, skip_first=False):
    max_line_length = 111
    if isinstance(iv, str):
        cs = struct.unpack("=" + "B" * len(iv), as_bytes(iv))
    elif isinstance(iv, (list, bytes)):
        cs = iv
    else:
        cs = [iv]

    line_length = indent
    indent_string = " " * indent
    if not skip_first:
        sys.stdout.write(indent_string)
    for c in cs:
        if isinstance(c, bytes):
            c = ord(c)
        out_str = "0x%02x" % c
        if line_length + len(out_str) > max_line_length:
            sys.stdout.write("\n%s" % indent_string)
            line_length = indent
        sys.stdout.write(out_str + " ")
        line_length += len(out_str) + 1
    sys.stdout.write("\n")

def get_cmdline_options():
    sk = "11223344556677889900112233445566"
    msg_dflt = "the message to be signed"
    ret = []
    sig_type = "NUL"

    # go through the commandline arguments
    try:
        (opts, args) = getopt.gnu_getopt(sys.argv[1:], "k:dgT:BAP")

    except getopt.GetoptError as err:
        print("Usage: %s [-B | -A | -P] [-g] [-d] [-k key] [-T test_file] [msg ...]" % sys.argv[0])
        sys.exit(str(err))

    for (opt, arg) in opts:
        if opt == "-k":
            sk = arg

        elif opt == "-d":
            enable_debug()

        elif opt == "-g":
            enable_genvec()

        elif opt == "-T":
            with open(arg, "r") as test_file:
                ret += [ tuple( binascii.unhexlify(val) \
                                for val in line.strip().split(' ') ) \
                         for line in test_file.readlines() ]

        elif opt == "-B":
            sig_type = "NUL"

        elif opt == "-A":
            sig_type = "AUG"

        elif opt == "-P":
            sig_type = "POP"

        else:
            raise RuntimeError("got unexpected option %s from getopt" % opt)

    # build up return value: (msg, sk) tuples from cmdline and any test files
    ret += [ (arg, sk) for arg in args ]
    if not ret:
        ret = [ (msg_dflt, sk) ]

    return (sig_type, ret)