Merge branch 'master' into add-crt-coefficients

* master:
  Also clean up this syntax
  Fixed a missing word in the RSA docs
  Fix comments in padding.py to be accurate
  add versionadded to cast5
  A few style nits in the docs
  add CAST5 support to changelog
  Changed .... lines to ~~~~ and s/Gnu\/Linux/Linux/
  Pypy is not a real word either apparently.
  Added Pypy note and fixed libffi's "spelling"
  Added Debian mention, extra missing packages
  Added a docs section on Linux installation
  remove some extra linebreaks
  add cast5 docs
  Syntax highlight the go code. Be mad Rob Pike.
  add cbc, cfb, ofb support to CAST5 (aka CAST128) for openssl & cc
  re-add CAST5 ECB support (OpenSSL & CC backends). fixes #417
  Switch this to a warning block
  Be clear about HKDF's applicability for password storage

Conflicts:
	docs/hazmat/primitives/rsa.rst

4 files changed, 37 insertions, 6 deletions

diff --git a/cryptography/hazmat/backends/commoncrypto/backend.py b/cryptography/hazmat/backends/commoncrypto/backend.py
index e5d4ee00..5c08a356 100644
--- a/cryptography/hazmat/backends/commoncrypto/backend.py
+++ b/cryptography/hazmat/backends/commoncrypto/backend.py
@@ -25,7 +25,7 @@ from cryptography.hazmat.backends.interfaces import (
 from cryptography.hazmat.bindings.commoncrypto.binding import Binding
 from cryptography.hazmat.primitives import interfaces, constant_time
 from cryptography.hazmat.primitives.ciphers.algorithms import (
-    AES, Blowfish, TripleDES, ARC4
+    AES, Blowfish, TripleDES, ARC4, CAST5
 )
 from cryptography.hazmat.primitives.ciphers.modes import (
     CBC, CTR, ECB, OFB, CFB, GCM
@@ -198,6 +198,18 @@ class Backend(object):
                 mode_cls,
                 mode_const
             )
+        for mode_cls, mode_const in [
+            (CBC, self._lib.kCCModeCBC),
+            (ECB, self._lib.kCCModeECB),
+            (CFB, self._lib.kCCModeCFB),
+            (OFB, self._lib.kCCModeOFB)
+        ]:
+            self._register_cipher_adapter(
+                CAST5,
+                self._lib.kCCAlgorithmCAST,
+                mode_cls,
+                mode_const
+            )
         self._register_cipher_adapter(
             ARC4,
             self._lib.kCCAlgorithmRC4,
diff --git a/cryptography/hazmat/backends/openssl/backend.py b/cryptography/hazmat/backends/openssl/backend.py
index ce37e5c8..8a4aeac5 100644
--- a/cryptography/hazmat/backends/openssl/backend.py
+++ b/cryptography/hazmat/backends/openssl/backend.py
@@ -26,7 +26,7 @@ from cryptography.hazmat.bindings.openssl.binding import Binding
 from cryptography.hazmat.primitives import interfaces, hashes
 from cryptography.hazmat.primitives.asymmetric import rsa
 from cryptography.hazmat.primitives.ciphers.algorithms import (
-    AES, Blowfish, Camellia, TripleDES, ARC4,
+    AES, Blowfish, Camellia, TripleDES, ARC4, CAST5
 )
 from cryptography.hazmat.primitives.ciphers.modes import (
     CBC, CTR, ECB, OFB, CFB, GCM,
@@ -153,6 +153,12 @@ class Backend(object):
                 mode_cls,
                 GetCipherByName("bf-{mode.name}")
             )
+        for mode_cls in [CBC, CFB, OFB, ECB]:
+            self.register_cipher_adapter(
+                CAST5,
+                mode_cls,
+                GetCipherByName("cast5-{mode.name}")
+            )
         self.register_cipher_adapter(
             ARC4,
             type(None),
diff --git a/cryptography/hazmat/primitives/ciphers/algorithms.py b/cryptography/hazmat/primitives/ciphers/algorithms.py
index 19cf1920..a5cfce92 100644
--- a/cryptography/hazmat/primitives/ciphers/algorithms.py
+++ b/cryptography/hazmat/primitives/ciphers/algorithms.py
@@ -90,6 +90,21 @@ class Blowfish(object):
         return len(self.key) * 8
 
 
+@utils.register_interface(interfaces.BlockCipherAlgorithm)
+@utils.register_interface(interfaces.CipherAlgorithm)
+class CAST5(object):
+    name = "CAST5"
+    block_size = 64
+    key_sizes = frozenset(range(40, 129, 8))
+
+    def __init__(self, key):
+        self.key = _verify_key_size(self, key)
+
+    @property
+    def key_size(self):
+        return len(self.key) * 8
+
+
 @utils.register_interface(interfaces.CipherAlgorithm)
 class ARC4(object):
     name = "RC4"
diff --git a/cryptography/hazmat/primitives/padding.py b/cryptography/hazmat/primitives/padding.py
index ddb2c63c..1717262c 100644
--- a/cryptography/hazmat/primitives/padding.py
+++ b/cryptography/hazmat/primitives/padding.py
@@ -86,8 +86,7 @@ class PKCS7(object):
 class _PKCS7PaddingContext(object):
     def __init__(self, block_size):
         self.block_size = block_size
-        # TODO: O(n ** 2) complexity for repeated concatentation, we should use
-        # zero-buffer (#193)
+        # TODO: more copies than necessary, we should use zero-buffer (#193)
         self._buffer = b""
 
     def update(self, data):
@@ -120,8 +119,7 @@ class _PKCS7PaddingContext(object):
 class _PKCS7UnpaddingContext(object):
     def __init__(self, block_size):
         self.block_size = block_size
-        # TODO: O(n ** 2) complexity for repeated concatentation, we should use
-        # zero-buffer (#193)
+        # TODO: more copies than necessary, we should use zero-buffer (#193)
         self._buffer = b""
 
     def update(self, data):