feat: 会话导出加密(.metona)，导入仅支持.metona格式

js/crypto.js

@@ -0,0 +1,86 @@
+/**
+ * Crypto - Metona 会话加密模块
+ *
+ * 文件格式: [8B magic "METONA1\0"][16B salt][12B IV][AES-256-GCM ciphertext]
+ * 后缀: .metona
+ */
+
+const MAGIC = new TextEncoder().encode('METONA1\0');
+const PASSPHRASE = 'metona-ollama-v2';
+const PBKDF2_ITERATIONS = 100000;
+
+/**
+ * 导入派生密钥
+ */
+async function deriveKey(salt) {
+    const keyMaterial = await crypto.subtle.importKey(
+        'raw',
+        new TextEncoder().encode(PASSPHRASE),
+        'PBKDF2',
+        false,
+        ['deriveKey']
+    );
+    return crypto.subtle.deriveKey(
+        { name: 'PBKDF2', salt, iterations: PBKDF2_ITERATIONS, hash: 'SHA-256' },
+        keyMaterial,
+        { name: 'AES-GCM', length: 256 },
+        false,
+        ['encrypt', 'decrypt']
+    );
+}
+
+/**
+ * 加密 JSON 数据 → .metona 二进制格式
+ * @param {object} data - 要加密的对象
+ * @returns {Blob} .metona 文件内容
+ */
+export async function encryptData(data) {
+    const json = new TextEncoder().encode(JSON.stringify(data));
+    const salt = crypto.getRandomValues(new Uint8Array(16));
+    const iv = crypto.getRandomValues(new Uint8Array(12));
+    const key = await deriveKey(salt);
+    const ciphertext = await crypto.subtle.encrypt({ name: 'AES-GCM', iv }, key, json);
+
+    // 拼接: magic + salt + iv + ciphertext
+    const blob = new Blob([MAGIC, salt, iv, ciphertext]);
+    return blob;
+}
+
+/**
+ * 解密 .metona 文件 → JSON 对象
+ * @param {ArrayBuffer} buffer - .metona 文件内容
+ * @returns {object} 解密后的对象
+ */
+export async function decryptData(buffer) {
+    const data = new Uint8Array(buffer);
+
+    // 校验 magic
+    const magic = data.slice(0, 8);
+    for (let i = 0; i < MAGIC.length; i++) {
+        if (magic[i] !== MAGIC[i]) {
+            throw new Error('不是有效的 .metona 文件');
+        }
+    }
+
+    const salt = data.slice(8, 24);
+    const iv = data.slice(24, 36);
+    const ciphertext = data.slice(36);
+
+    const key = await deriveKey(salt);
+    let decrypted;
+    try {
+        decrypted = await crypto.subtle.decrypt({ name: 'AES-GCM', iv }, key, ciphertext);
+    } catch {
+        throw new Error('文件已损坏或格式不正确');
+    }
+
+    const json = new TextDecoder().decode(decrypted);
+    return JSON.parse(json);
+}
+
+/**
+ * 检查文件是否为 .metona 格式
+ */
+export function isMetonaFile(file) {
+    return file.name.endsWith('.metona');
+}