gecko/python/PyECC/ecc/shacrypt.py
David Keeler 7640a01369 bug 1190603 - import PyECC library r=gps,gerv
Obtained from https://github.com/amintos/PyECC.git
(commit 1bfd3a41410c3650e57d58f7bd016bb0819af250)
2015-08-03 15:17:00 -07:00

39 lines
1.1 KiB
Python

# ------------------------------------------------------------------------------
#
# SHA-512-BASED FEISTEL CIPHER
# by Toni Mattis
#
# Feistel Function: SHA-512(Block || Key)
# Key Size: Fully Dynamic
# Block Size: 1024 Bits
# Rounds: User-Specified
#
# ------------------------------------------------------------------------------
from hashlib import sha512
BPOS = tuple(range(64))
def enc_block(block, key, rounds = 16):
x = block[:64]
y = block[64:]
for i in xrange(rounds):
h = sha512(x + key).digest()
y = ''.join([chr(ord(y[k]) ^ ord(h[k])) for k in BPOS])
h = sha512(y + key).digest()
x = ''.join([chr(ord(x[k]) ^ ord(h[k])) for k in BPOS])
return x + y
def dec_block(block, key, rounds = 16):
x = block[:64]
y = block[64:]
for i in xrange(rounds):
h = sha512(y + key).digest()
x = ''.join([chr(ord(x[k]) ^ ord(h[k])) for k in BPOS])
h = sha512(x + key).digest()
y = ''.join([chr(ord(y[k]) ^ ord(h[k])) for k in BPOS])
return x + y