diff --git a/codebreak/__init__.py b/codebreak/__init__.py
new file mode 100755
index 0000000..2dfc0bb
--- /dev/null
+++ b/codebreak/__init__.py
@@ -0,0 +1,149 @@
+#! /usr/bin/python
+# -*- coding: utf-8 -*-
+
+import sys
+
+printable = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890!@#$%^&*()[]{}`~/=\\?+|\',."<> '
+
+def unpack(fmt, buf):
+    """Unpack buf based on fmt, return the rest as a string."""
+
+    size = struct.calcsize(fmt)
+    vals = struct.unpack(fmt, buf[:size])
+    return vals + (buf[size:],)
+
+
+def to_printable(c):
+    if c in printable:
+        return c
+    elif c == '\0':
+        return '␀'
+    else:
+        return '·'
+
+
+def hexdump(buf, f=sys.stdout):
+    "Print a hex dump of buf"
+
+    offset = 0
+
+    while buf:
+        s = buf[:16]
+        o = [('%02x' % ord(c)) for c in s] + (['  '] * (16 - len(s)))
+        p = [to_printable(c) for c in s]
+
+        f.write('%08x  ' % offset)
+
+        f.write(' '.join(o[:8]))
+        f.write('  ')
+        f.write(' '.join(o[8:]))
+
+        f.write('  ║')
+
+        f.write(''.join(p))
+
+        f.write('║\n')
+
+        buf = buf[16:]
+        offset += 16
+
+
+def cstring(buf):
+    "Return buf if buf were a C-style (NULL-terminate) string"
+
+    i = buf.index('\0')
+    return buf[:i]
+
+
+def md5sum(txt):
+    return md5.new(txt).hexdigest()
+
+
+def assert_equal(a, b):
+    assert a == b, ('%r != %r' % (a, b))
+
+
+def assert_in(a, *b):
+    assert a in b, ('%r not in %r' % (a, b))
+
+
+##
+## Binary stuff
+##
+
+def bin(i):
+    """Return the binary representation of i"""
+
+    r = []
+    while i > 0:
+        r.append(i % 2)
+        i = i >> 1
+    r.reverse()
+    s = ''.join(str(x) for x in r)
+    return s
+
+class bitvector:
+    def __init__(self, i, length=None):
+        if type(i) == type(''):
+            self._val = 0
+            for c in i:
+                self._val <<= 8
+                self._val += ord(c)
+            if length is not None:
+                self._len = length
+            else:
+                self._len = len(i) * 8
+        else:
+            self._val = i
+            if length is not None:
+                self._len = length
+            else:
+                self._len = 0
+                while i > 0:
+                    i >>= 1
+                    self._len += 1
+
+    def __len__(self):
+        return self._len
+
+    def __getitem__(self, idx):
+        if idx > self._len:
+            raise IndexError()
+        idx = self._len - idx
+        return int((self._val >> idx) & 1)
+
+    def __getslice__(self, a, b):
+        if b > self._len:
+            b = self._len
+        i = self._val >> (self._len - b)
+        l = b - a
+        mask = (1 << l) - 1
+        return bitvector(i & mask, length=l)
+
+    def __iter__(self):
+        v = self._val
+        for i in xrange(self._len):
+            yield int(v & 1)
+            v >>= 1
+
+    def __str__(self):
+        r = ''
+        v = self._val
+        i = self._len
+        while i > 8:
+            o = ((v >> (i - 8)) & 0xFF)
+            r += chr(o)
+            i -= 8
+        if i > 0:
+            o = v & ((1 << i) - 1)
+            r += chr(o)
+        return r
+
+    def __int__(self):
+        return self._val
+
+    def __repr__(self):
+        l = list(self)
+        l.reverse()
+        return '<bitvector ' + ''.join(str(x) for x in l) + '>'
+
diff --git a/codebreak.py b/codebreak/crypto.py
similarity index 76%
rename from codebreak.py
rename to codebreak/crypto.py
index 778d167..87684df 100644
--- a/codebreak.py
+++ b/codebreak/crypto.py
@@ -35,86 +35,6 @@ english_frequency = {'A': .08167,
                      'Y': .01974,
                      'Z': .00074}
 
-##
-## Binary stuff
-##
-
-def bin(i):
-    """Return the binary representation of i"""
-
-    r = []
-    while i > 0:
-        r.append(i % 2)
-        i = i >> 1
-    r.reverse()
-    s = ''.join(str(x) for x in r)
-    return s
-
-class bitvector:
-    def __init__(self, i, length=None):
-        if type(i) == type(''):
-            self._val = 0
-            for c in i:
-                self._val <<= 8
-                self._val += ord(c)
-            if length is not None:
-                self._len = length
-            else:
-                self._len = len(i) * 8
-        else:
-            self._val = i
-            if length is not None:
-                self._len = length
-            else:
-                self._len = 0
-                while i > 0:
-                    i >>= 1
-                    self._len += 1
-
-    def __len__(self):
-        return self._len
-
-    def __getitem__(self, idx):
-        if idx > self._len:
-            raise IndexError()
-        idx = self._len - idx
-        return int((self._val >> idx) & 1)
-
-    def __getslice__(self, a, b):
-        if b > self._len:
-            b = self._len
-        i = self._val >> (self._len - b)
-        l = b - a
-        mask = (1 << l) - 1
-        return bitvector(i & mask, length=l)
-
-    def __iter__(self):
-        v = self._val
-        for i in xrange(self._len):
-            yield int(v & 1)
-            v >>= 1
-
-    def __str__(self):
-        r = ''
-        v = self._val
-        i = self._len
-        while i > 8:
-            o = ((v >> (i - 8)) & 0xFF)
-            r += chr(o)
-            i -= 8
-        if i > 0:
-            o = v & ((1 << i) - 1)
-            r += chr(o)
-        return r
-
-    def __int__(self):
-        return self._val
-
-    def __repr__(self):
-        l = list(self)
-        l.reverse()
-        return '<bitvector ' + ''.join(str(x) for x in l) + '>'
-
 ##
 ## Statistical stuff
 ##
diff --git a/resequence.py b/codebreak/resequence.py
similarity index 100%
rename from resequence.py
rename to codebreak/resequence.py