Rewrites provided by rleftwich@lightkeeper.com

This commit (mostly) replaces the code removed by the reversions of:

  2244eca
  75f44f9

Those commits were provided by individuals who hadn't signed a Google
Contributor License Agreement, and couldn't be tracked down to sign one.
By reverting them and asking Robert to reimplement them from scratch,
we removed them from the codebase without losing the relevant functionality
(though we did lose a unit test).

cpp/src/tools/swtoolkit/site_scons/site_init.py

@@ -65,6 +65,8 @@ def _HostPlatform():
       'openbsd4': 'BSD',
       'freebsd6': 'BSD',
       'freebsd7': 'BSD',
+      'freebsd8': 'BSD',
+      'freebsd9': 'BSD',
       'netbsd4': 'BSD',
       'netbsd5': 'BSD',
   }

python/src/keyczar/keyczar.py

@@ -776,11 +776,11 @@ def session_material(self):
     """
     return self._encrypted_session_material
 
-  def Encrypt(self, plaintext):
+  def Encrypt(self, plaintext, encoder=util.Base64WSEncode):
     """
     Encrypts the given plaintext with the session key and returns the base 64-encoded result.
     """
-    return self._session.crypter.Encrypt(plaintext)
+    return self._session.crypter.Encrypt(plaintext, encoder)
 
 
 class SessionDecrypter(object):
@@ -792,12 +792,12 @@ class SessionDecrypter(object):
   def __init__(self, crypter, session_material):
     self._session = _Session.LoadPackedKey(crypter.Decrypt(session_material))
 
-  def Decrypt(self, ciphertext):
+  def Decrypt(self, ciphertext, decoder=util.Base64WSDecode):
     """
     Decrypts the given base 64-encoded ciphertext with the session key and returns the
     decrypted plaintext.
     """
-    return self._session.crypter.Decrypt(ciphertext)
+    return self._session.crypter.Decrypt(ciphertext, decoder)
 
 
 class SignedSessionEncrypter(object):