Fix some stuff and sort of implement proving

static/js/modules/crypto/paillier.js

@@ -86,7 +86,7 @@ export class ReadOnlyCyphertext {
         this.cyphertext = (this.cyphertext * c.cyphertext) % this.pubKey.n ** 2n;
     }
 
-    prove(plainText, a) {
+    prove(tag, plainText, a) {
         return new ProofSessionVerifier(this, plainText, a);
     }
 }