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#!/usr/bin/python
import sys, struct, traceback
from Crypto.Util import number
def inflate_long(s, always_positive=0):
"turns a normalized byte string into a long-int (adapted from Crypto.Util.number)"
out = 0L
negative = 0
if not always_positive and (len(s) > 0) and (ord(s[0]) >= 0x80):
negative = 1
if len(s) % 4:
filler = '\x00'
if negative:
filler = '\xff'
s = filler * (4 - len(s) % 4) + s
for i in range(0, len(s), 4):
out = (out << 32) + struct.unpack('>I', s[i:i+4])[0]
if negative:
out -= (1L << (8 * len(s)))
return out
def deflate_long(n, add_sign_padding=1):
"turns a long-int into a normalized byte string (adapted from Crypto.Util.number)"
# after much testing, this algorithm was deemed to be the fastest
s = ''
n = long(n)
while (n != 0) and (n != -1):
s = struct.pack('>I', n & 0xffffffffL) + s
n = n >> 32
# strip off leading zeros, FFs
for i in enumerate(s):
if (n == 0) and (i[1] != '\000'):
break
if (n == -1) and (i[1] != '\xff'):
break
else:
# degenerate case, n was either 0 or -1
i = (0,)
if n == 0:
s = '\000'
else:
s = '\xff'
s = s[i[0]:]
if add_sign_padding:
if (n == 0) and (ord(s[0]) >= 0x80):
s = '\x00' + s
if (n == -1) and (ord(s[0]) < 0x80):
s = '\xff' + s
return s
def format_binary_weird(data):
out = ''
for i in enumerate(data):
out += '%02X' % ord(i[1])
if i[0] % 2:
out += ' '
if i[0] % 16 == 15:
out += '\n'
return out
def format_binary(data, prefix=''):
x = 0
out = []
while len(data) > x + 16:
out.append(format_binary_line(data[x:x+16]))
x += 16
if x < len(data):
out.append(format_binary_line(data[x:]))
return [prefix + x for x in out]
def format_binary_line(data):
left = ' '.join(['%02X' % ord(c) for c in data])
right = ''.join([('.%c..' % c)[(ord(c)+61)//94] for c in data])
return '%-50s %s' % (left, right)
def hexify(s):
"turn a string into a hex sequence"
return ''.join(['%02X' % ord(c) for c in s])
def safe_string(s):
out = ''
for c in s:
if (ord(c) >= 32) and (ord(c) <= 127):
out += c
else:
out += '%%%02X' % ord(c)
return out
# ''.join([['%%%02X' % ord(c), c][(ord(c) >= 32) and (ord(c) <= 127)] for c in s])
def bit_length(n):
norm = deflate_long(n, 0)
hbyte = ord(norm[0])
bitlen = len(norm) * 8
while not (hbyte & 0x80):
hbyte <<= 1
bitlen -= 1
return bitlen
def generate_prime(bits, randpool):
hbyte_mask = pow(2, bits % 8) - 1
x = randpool.get_bytes((bits+7) // 8)
if hbyte_mask > 0:
x = chr(ord(x[0]) & hbyte_mask) + x[1:]
n = inflate_long(x, 1)
n |= 1
n |= (1 << (bits - 1))
while 1:
# loop catches the case where we increment n into a higher bit-range
while not number.isPrime(n):
n += 2
if bit_length(n) == bits:
return n
def tb_strings():
return ''.join(traceback.format_exception(*sys.exc_info())).split('\n')
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