Fix now-broken test cases and change lots of things over to promises

js/crypto.js

@@ -1,15 +1,26 @@
 function HmacSHA256(key, input) {
+	input = assertIsArrayBuffer(input);
+	key = assertIsArrayBuffer(key);
 	return window.crypto.subtle.sign({name: "HMAC", hash: "SHA-256"}, key, input);
 }
 
 function encryptAESCTR(input, key, counter) {
+	input = assertIsArrayBuffer(input);
+	key = assertIsArrayBuffer(key);
+	counter = assertIsArrayBuffer(counter);
 	return window.crypto.subtle.encrypt({name: "AES-CTR", counter: counter}, key, input);
 }
 
 function decryptAESCTR(input, key, counter) {
+	input = assertIsArrayBuffer(input);
+	key = assertIsArrayBuffer(key);
+	counter = assertIsArrayBuffer(counter);
 	return window.crypto.subtle.decrypt({name: "AES-CTR", counter: counter}, key, input);
 }
 
 function decryptAESCBC(input, key, iv) {
+	input = assertIsArrayBuffer(input);
+	key = assertIsArrayBuffer(key);
+	iv = assertIsArrayBuffer(iv);
 	return window.crypto.subtle.decrypt({name: "AES-CBC", iv: iv}, key, input);
 }