Fixes bad zero-prefix padding bug in older _int2bytes to pass all tests.
diff --git a/rsa/transform.py b/rsa/transform.py
index 9ba2fe7..9abc6ae 100644
--- a/rsa/transform.py
+++ b/rsa/transform.py
@@ -33,10 +33,7 @@
import binascii
from struct import pack
from rsa import common
-from rsa._compat import is_integer, b, byte, get_word_alignment
-
-
-ZERO_BYTE = b('\x00')
+from rsa._compat import is_integer, b, byte, get_word_alignment, ZERO_BYTE, EMPTY_BYTE
def bytes2int(raw_bytes):
@@ -74,14 +71,19 @@
raise ValueError('Negative numbers cannot be used: %i' % number)
# Do some bounds checking
- needed_bytes = common.byte_size(number)
+ if number == 0:
+ needed_bytes = 1
+ raw_bytes = [ZERO_BYTE]
+ else:
+ needed_bytes = common.byte_size(number)
+ raw_bytes = []
+
if block_size > 0:
if needed_bytes > block_size:
raise OverflowError('Needed %i bytes for number, but block size '
'is %i' % (needed_bytes, block_size))
# Convert the number to bytes.
- raw_bytes = []
while number > 0:
raw_bytes.insert(0, byte(number & 0xFF))
number >>= 8
@@ -90,9 +92,9 @@
if block_size > 0:
padding = (block_size - needed_bytes) * ZERO_BYTE
else:
- padding = b('')
+ padding = EMPTY_BYTE
- return padding + b('').join(raw_bytes)
+ return padding + EMPTY_BYTE.join(raw_bytes)
def bytes_leading(raw_bytes, needle=ZERO_BYTE):