diff --git a/paramiko/message.py b/paramiko/message.py
index 1a5151c..bcdfdba 100644
--- a/paramiko/message.py
+++ b/paramiko/message.py
@@ -111,7 +111,7 @@ class Message (object):
         """
         b = self.packet.read(n)
         if len(b) < n:
-            return '\x00'*n
+            return b + '\x00' * (n - len(b))
         return b
 
     def get_byte(self):
diff --git a/paramiko/util.py b/paramiko/util.py
index 8abdc0c..e5ab076 100644
--- a/paramiko/util.py
+++ b/paramiko/util.py
@@ -135,6 +135,8 @@ def safe_string(s):
 def bit_length(n):
     norm = deflate_long(n, 0)
     hbyte = ord(norm[0])
+    if hbyte == 0:
+        return 1
     bitlen = len(norm) * 8
     while not (hbyte & 0x80):
         hbyte <<= 1