diff --git a/docs/hazmat/primitives/cryptographic-hashes.rst b/docs/hazmat/primitives/cryptographic-hashes.rst
index 76ca20c..20fa23c 100644
--- a/docs/hazmat/primitives/cryptographic-hashes.rst
+++ b/docs/hazmat/primitives/cryptographic-hashes.rst
@@ -12,9 +12,9 @@
     results (with a high probability) in different digests.
 
     This is an implementation of
-    :class:`cryptography.hazmat.primitives.interfaces.HashContext` meant to
+    :class:`~cryptography.hazmat.primitives.interfaces.HashContext` meant to
     be used with
-    :class:`cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+    :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
     implementations to provide an incremental interface to calculating
     various message digests.
 
@@ -102,7 +102,8 @@
 .. warning::
 
     MD5 is a deprecated hash algorithm that has practical known collision
-    attacks. You are strongly discouraged from using it.
+    attacks. You are strongly discouraged from using it. Existing applications
+    should strongly consider moving away.
 
 .. class:: MD5()
 
diff --git a/docs/hazmat/primitives/symmetric-encryption.rst b/docs/hazmat/primitives/symmetric-encryption.rst
index 5f1a64a..5542e83 100644
--- a/docs/hazmat/primitives/symmetric-encryption.rst
+++ b/docs/hazmat/primitives/symmetric-encryption.rst
@@ -14,13 +14,22 @@
 
 
 Symmetric encryption is a way to encrypt (hide the plaintext value) material
-where the encrypter and decrypter both use the same key.
+where the encrypter and decrypter both use the same key. Note that symmetric
+encryption is **not** sufficient for most applications, because it only
+provides secrecy (an attacker can't see the message) but not authenticity (an
+attacker can create bogus messages and force the application to decrypt them).
+For this reason it is *strongly* reccomended to combine encryption with a
+message authentication code, such as :doc:`HMAC </hazmat/primitives/hmac>`, in
+an "encrypt-then-MAC" formulation as `described by Colin Percival`_.
 
 .. class:: Cipher(algorithm, mode)
 
-    Cipher objects combine an algorithm (such as AES) with a mode (such as
-    CBC, CTR, or GCM). A simple example of encrypting (and then decrypting)
-    content with AES is:
+    Cipher objects combine an algorithm (such as
+    :class:`~cryptography.hazmat.primitives.ciphers.algorithms.AES`) with a
+    mode (such as
+    :class:`~cryptography.hazmat.primitives.ciphers.modes.CBC` or
+    :class:`~cryptography.hazmat.primitives.ciphers.modes.CTR`). A simple
+    example of encrypting (and then decrypting) content with AES is:
 
     .. doctest::
 
@@ -143,8 +152,7 @@
 
     Blowfish is a block cipher developed by Bruce Schneier. It is known to be
     susceptible to attacks when using weak keys. The author has recommended
-    that users of Blowfish move to newer algorithms like
-    :class:`AES`.
+    that users of Blowfish move to newer algorithms, such as :class:`AES`.
 
     :param bytes key: The secret key, 32-448 bits in length (in increments of
                       8).  This must be kept secret.
@@ -252,3 +260,6 @@
     ciphers. Each block of data is encrypted in the same way. This means
     identical plaintext blocks will always result in identical ciphertext
     blocks, and thus result in information leakage
+
+
+.. _`described by Colin Percival`: http://www.daemonology.net/blog/2009-06-11-cryptographic-right-answers.html