Minor correction to a statement about consequences of breaking ECDHP.

Signed-off-by: Daira Hopwood <daira@jacaranda.org>

protocol/protocol.tex

@@ -2595,7 +2595,7 @@ The motivations for this change were as follows:
         a nonce as described below, as input to the KDF. Note that because
         $\TransmitPublic$ is included in the KDF input, being able to break the
         Elliptic Curve Diffie-Hellman Problem on Curve25519 (without breaking
-        $\SymCipher$ as an authenticated encryption scheme or $\Blake{256}$ as
+        $\SymSpecific$ as an authenticated encryption scheme or $\Blake{256}$ as
         a KDF) would not help to decrypt the \notesCiphertext unless
         $\TransmitPublic$ is known or guessed.
   \item The KDF also takes a public seed $\hSig$ as input. This can be modeled