path: root/frozen_deps/Crypto/Util/RFC1751.py

# rfc1751.py : Converts between 128-bit strings and a human-readable
# sequence of words, as defined in RFC1751: "A Convention for
# Human-Readable 128-bit Keys", by Daniel L. McDonald.
#
# Part of the Python Cryptography Toolkit
#
# Written by Andrew M. Kuchling and others
#
# ===================================================================
# The contents of this file are dedicated to the public domain.  To
# the extent that dedication to the public domain is not available,
# everyone is granted a worldwide, perpetual, royalty-free,
# non-exclusive license to exercise all rights associated with the
# contents of this file for any purpose whatsoever.
# No rights are reserved.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
# ===================================================================

__revision__ = "$Id$"


import binascii
from Crypto.Util.py3compat import *
from functools import reduce

binary={0:'0000', 1:'0001', 2:'0010', 3:'0011', 4:'0100', 5:'0101',
        6:'0110', 7:'0111', 8:'1000', 9:'1001', 10:'1010', 11:'1011',
        12:'1100', 13:'1101', 14:'1110', 15:'1111'}

def _key2bin(s):
    "Convert a key into a string of binary digits"
    kl=[bord(x) for x in s]
    kl=[binary[x>>4]+binary[x&15] for x in kl]
    return ''.join(kl)

def _extract(key, start, length):
    """Extract a bitstring(2.x)/bytestring(2.x) from a string of binary digits, and return its
    numeric value."""
    k=key[start:start+length]
    return reduce(lambda x,y: x*2+ord(y)-48, k, 0)

def key_to_english (key):
    """key_to_english(key:string(2.x)/bytes(3.x)) : string
    Transform an arbitrary key into a string containing English words.
    The key length must be a multiple of 8.
    """
    english=''
    for index in range(0, len(key), 8): # Loop over 8-byte subkeys
        subkey=key[index:index+8]
        # Compute the parity of the key
        skbin=_key2bin(subkey) ; p=0
        for i in range(0, 64, 2): p=p+_extract(skbin, i, 2)
        # Append parity bits to the subkey
        skbin=_key2bin(subkey+bchr((p<<6) & 255))
        for i in range(0, 64, 11):
            english=english+wordlist[_extract(skbin, i, 11)]+' '

    return english[:-1]                 # Remove the trailing space

def english_to_key (s):
    """english_to_key(string):string(2.x)/bytes(2.x)
    Transform a string into a corresponding key.
    The string must contain words separated by whitespace; the number
    of words must be a multiple of 6.
    """

    L=s.upper().split() ; key=b('')
    for index in range(0, len(L), 6):
        sublist=L[index:index+6] ; char=9*[0] ; bits=0
        for i in sublist:
            index = wordlist.index(i)
            shift = (8-(bits+11)%8) %8
            y = index << shift
            cl, cc, cr = (y>>16), (y>>8)&0xff, y & 0xff
            if (shift>5):
                char[bits>>3] = char[bits>>3] | cl
                char[(bits>>3)+1] = char[(bits>>3)+1] | cc
                char[(bits>>3)+2] = char[(bits>>3)+2] | cr
            elif shift>-3:
                char[bits>>3] = char[bits>>3] | cc
                char[(bits>>3)+1] = char[(bits>>3)+1] | cr
            else: char[bits>>3] = char[bits>>3] | cr
            bits=bits+11
        subkey=reduce(lambda x,y:x+bchr(y), char, b(''))

        # Check the parity of the resulting key
        skbin=_key2bin(subkey)
        p=0
        for i in range(0, 64, 2): p=p+_extract(skbin, i, 2)
        if (p&3) != _extract(skbin, 64, 2):
            raise ValueError("Parity error in resulting key")
        key=key+subkey[0:8]
    return key

wordlist=[ "A", "ABE", "ACE", "ACT", "AD", "ADA", "ADD",
   "AGO", "AID", "AIM", "AIR", "ALL", "ALP", "AM", "AMY", "AN", "ANA",
   "AND", "ANN", "ANT", "ANY", "APE", "APS", "APT", "ARC", "ARE", "ARK",
   "ARM", "ART", "AS", "ASH", "ASK", "AT", "ATE", "AUG", "AUK", "AVE",
   "AWE", "AWK", "AWL", "AWN", "AX", "AYE", "BAD", "BAG", "BAH", "BAM",
   "BAN", "BAR", "BAT", "BAY", "BE", "BED", "BEE", "BEG", "BEN", "BET",
   "BEY", "BIB", "BID", "BIG", "BIN", "BIT", "BOB", "BOG", "BON", "BOO",
   "BOP", "BOW", "BOY", "BUB", "BUD", "BUG", "BUM", "BUN", "BUS", "BUT",
   "BUY", "BY", "BYE", "CAB", "CAL", "CAM", "CAN", "CAP", "CAR", "CAT",
   "CAW", "COD", "COG", "COL", "CON", "COO", "COP", "COT", "COW", "COY",
   "CRY", "CUB", "CUE", "CUP", "CUR", "CUT", "DAB", "DAD", "DAM", "DAN",
   "DAR", "DAY", "DEE", "DEL", "DEN", "DES", "DEW", "DID", "DIE", "DIG",
   "DIN", "DIP", "DO", "DOE", "DOG", "DON", "DOT", "DOW", "DRY", "DUB",
   "DUD", "DUE", "DUG", "DUN", "EAR", "EAT", "ED", "EEL", "EGG", "EGO",
   "ELI", "ELK", "ELM", "ELY", "EM", "END", "EST", "ETC", "EVA", "EVE",
   "EWE", "EYE", "FAD", "FAN", "FAR", "FAT", "FAY", "FED", "FEE", "FEW",
   "FIB", "FIG", "FIN", "FIR", "FIT", "FLO", "FLY", "FOE", "FOG", "FOR",
   "FRY", "FUM", "FUN", "FUR", "GAB", "GAD", "GAG", "GAL", "GAM", "GAP",
   "GAS", "GAY", "GEE", "GEL", "GEM", "GET", "GIG", "GIL", "GIN", "GO",
   "GOT", "GUM", "GUN", "GUS", "GUT", "GUY", "GYM", "GYP", "HA", "HAD",
   "HAL", "HAM", "HAN", "HAP", "HAS", "HAT", "HAW", "HAY", "HE", "HEM",
   "HEN", "HER", "HEW", "HEY", "HI", "HID", "HIM", "HIP", "HIS", "HIT",
   "HO", "HOB", "HOC", "HOE", "HOG", "HOP", "HOT", "HOW", "HUB", "HUE",
   "HUG", "HUH", "HUM", "HUT", "I", "ICY", "IDA", "IF", "IKE", "ILL",
   "INK", "INN", "IO", "ION", "IQ", "IRA", "IRE", "IRK", "IS", "IT",
   "ITS", "IVY", "JAB", "JAG", "JAM", "JAN", "JAR", "JAW", "JAY", "JET",
   "JIG", "JIM", "JO", "JOB", "JOE", "JOG", "JOT", "JOY", "JUG", "JUT",
   "KAY", "KEG", "KEN", "KEY", "KID", "KIM", "KIN", "KIT", "LA", "LAB",
   "LAC", "LAD", "LAG", "LAM", "LAP", "LAW", "LAY", "LEA", "LED", "LEE",
   "LEG", "LEN", "LEO", "LET", "LEW", "LID", "LIE", "LIN", "LIP", "LIT",
   "LO", "LOB", "LOG", "LOP", "LOS", "LOT", "LOU", "LOW", "LOY", "LUG",
   "LYE", "MA", "MAC", "MAD", "MAE", "MAN", "MAO", "MAP", "MAT", "MAW",
   "MAY", "ME", "MEG", "MEL", "MEN", "MET", "MEW", "MID", "MIN", "MIT",
   "MOB", "MOD", "MOE", "MOO", "MOP", "MOS", "MOT", "MOW", "MUD", "MUG",
   "MUM", "MY", "NAB", "NAG", "NAN", "NAP", "NAT", "NAY", "NE", "NED",
   "NEE", "NET", "NEW", "NIB", "NIL", "NIP", "NIT", "NO", "NOB", "NOD",
   "NON", "NOR", "NOT", "NOV", "NOW", "NU", "NUN", "NUT", "O", "OAF",
   "OAK", "OAR", "OAT", "ODD", "ODE", "OF", "OFF", "OFT", "OH", "OIL",
   "OK", "OLD", "ON", "ONE", "OR", "ORB", "ORE", "ORR", "OS", "OTT",
   "OUR", "OUT", "OVA", "OW", "OWE", "OWL", "OWN", "OX", "PA", "PAD",
   "PAL", "PAM", "PAN", "PAP", "PAR", "PAT", "PAW", "PAY", "PEA", "PEG",
   "PEN", "PEP", "PER", "PET", "PEW", "PHI", "PI", "PIE", "PIN", "PIT",
   "PLY", "PO", "POD", "POE", "POP", "POT", "POW", "PRO", "PRY", "PUB",
   "PUG", "PUN", "PUP", "PUT", "QUO", "RAG", "RAM", "RAN", "RAP", "RAT",
   "RAW", "RAY", "REB", "RED"<