encryption code separated into its own file

static/js/encryption.js

@@ -0,0 +1,189 @@
+let globalEncryptionCallback = null;
+
+function handleEncryption(requireEncryption, modal, callback) {
+    if (requireEncryption && globalEncryptionKey === null) {
+        globalEncryptionCallback = callback;
+
+        if (!modal) {
+            $("#noteDetailWrapper").hide();
+        }
+
+        $("#encryptionPasswordDialog").dialog({
+            modal: modal,
+            width: 400,
+            open: function() {
+                if (!modal) {
+                    // dialog steals focus for itself, which is not what we want for non-modal (viewing)
+                    getNodeByKey(globalNote.detail.note_id).setFocus();
+                }
+            }
+        });
+    }
+    else {
+        callback();
+    }
+}
+
+// currently not configurable
+const globalEncryptionKeyTimeToLive = 10 * 60 * 1000; // in milliseconds
+
+let globalEncryptionKey = null;
+let globalLastEncryptionOperationDate = null;
+
+function deriveEncryptionKey(password) {
+    // why this is done is explained here: https://github.com/ricmoo/scrypt-js - "Encoding notes"
+    const normalizedPassword = password.normalize('NFKC');
+    const salt = "dc73b57736511340f132e4b5521d178afa6311c45e0c25e6a9339038507852a6";
+
+    const passwordBuffer = new buffer.SlowBuffer(normalizedPassword);
+    const saltBuffer = new buffer.SlowBuffer(salt);
+
+    // this settings take ~500ms on my laptop
+    const N = 16384, r = 16, p = 1;
+    // 32 byte key - AES 256
+    const dkLen = 32;
+
+    const startedDate = new Date();
+
+    return new Promise((resolve, reject) => {
+        scrypt(passwordBuffer, saltBuffer, N, r, p, dkLen, function (error, progress, key) {
+            if (error) {
+                console.log("Error: " + error);
+
+                reject();
+            }
+            else if (key) {
+                console.log("Computation took " + (new Date().getTime() - startedDate.getTime()) + "ms");
+
+                $.ajax({
+                    url: baseUrl + 'password/verify',
+                    type: 'POST',
+                    data: JSON.stringify({
+                        password: sha256(key)
+                    }),
+                    contentType: "application/json",
+                    success: function (result) {
+                        if (result.valid) {
+                            resolve(key);
+                        }
+                        else {
+                            alert("Wrong password");
+
+                            reject();
+                        }
+                    }
+                });
+            }
+            else {
+                // update UI with progress complete
+            }
+        });
+    });
+}
+
+$("#encryptionPasswordForm").submit(function() {
+    const password = $("#encryptionPassword").val();
+    $("#encryptionPassword").val("");
+
+    deriveEncryptionKey(password).then(key => {
+        $("#noteDetailWrapper").show();
+        $("#encryptionPasswordDialog").dialog("close");
+
+        globalEncryptionKey = key;
+
+        if (globalEncryptionCallback !== null) {
+            globalEncryptionCallback();
+
+            globalEncryptionCallback = null;
+        }
+    });
+
+    return false;
+});
+
+function getAes() {
+    globalLastEncryptionOperationDate = new Date();
+
+    setTimeout(function() {
+        if (new Date().getTime() - globalLastEncryptionOperationDate.getTime() > globalEncryptionKeyTimeToLive) {
+            globalEncryptionKey = null;
+
+            if (globalNote.detail.encryption > 0) {
+                loadNote(globalNote.detail.note_id);
+            }
+        }
+    }, globalEncryptionKeyTimeToLive + 1000);
+
+    return new aesjs.ModeOfOperation.ctr(globalEncryptionKey, new aesjs.Counter(5));
+}
+
+function encryptNoteIfNecessary(note) {
+    if (note.detail.encryption === 0) {
+        return note;
+    }
+    else {
+        return encryptNote(note);
+    }
+}
+
+function encryptNote(note) {
+    const aes = getAes();
+    const noteJson = note.detail.note_text;
+
+    const noteBytes = aesjs.utils.utf8.toBytes(noteJson);
+
+    const encryptedBytes = aes.encrypt(noteBytes);
+
+    // To print or store the binary data, you may convert it to hex
+    note.detail.note_text = uint8ToBase64(encryptedBytes);
+
+    return note;
+}
+
+function encryptNoteAndSendToServer() {
+    handleEncryption(true, true, () => {
+        const note = globalNote;
+
+        updateNoteFromInputs(note);
+
+        encryptNote(note);
+
+        note.detail.encryption = 1;
+
+        saveNoteToServer(note);
+
+        setNoteBackgroundIfEncrypted(note);
+    });
+}
+
+function decryptNoteAndSendToServer() {
+    handleEncryption(true, true, () => {
+        const note = globalNote;
+
+        updateNoteFromInputs(note);
+
+        note.detail.encryption = 0;
+
+        saveNoteToServer(note);
+
+        setNoteBackgroundIfEncrypted(note);
+    });
+}
+
+function decryptNoteIfNecessary(note) {
+    if (note.detail.encryption === 1) {
+        return decryptNote(note.detail.note_text);
+    }
+    else {
+        return note.detail.note_text;
+    }
+}
+
+function decryptNote(encryptedBase64) {
+    const aes = getAes();
+    const encryptedBytes = base64ToUint8Array(encryptedBase64);
+
+    const decryptedBytes = aes.decrypt(encryptedBytes);
+
+    return aesjs.utils.utf8.fromBytes(decryptedBytes);
+}