Change "proof" to "cryptographic proof".

index.html

@@ -6707,7 +6707,7 @@ <h3>Proofs (Signatures)</h3>
         <p>
 The securing mechanism used to prove that the information in a
 [=verifiable credential=] or [=verifiable presentation=] was not tampered
-with is called a <em>proof</em>. There are many types of cryptographic proofs
+with is called a <em>cryptographic proof</em>. There are many types of cryptographic proofs
 including, but not limited to, digital signatures and zero-knowledge proofs. In
 general, when verifying cryptographic proofs, implementations are expected to
 ensure: