feat(encrypt): Add XOR and ChaCha20 encryption with low-end device optimization and openssl support. (#1186)

Add ChaCha20 XOR algorithm, extend AES-GCM-256 capabilities, and integrate OpenSSL support.

---------

Co-authored-by: Sijie.Sun <sunsijie@buaa.edu.cn>

easytier/src/common/global_ctx.rs

@@ -296,6 +296,29 @@ impl GlobalCtx {
         key
     }
 
+    pub fn get_256_key(&self) -> [u8; 32] {
+        let mut key = [0u8; 32];
+        let secret = self
+            .config
+            .get_network_identity()
+            .network_secret
+            .unwrap_or_default();
+        // fill key according to network secret
+        let mut hasher = DefaultHasher::new();
+        hasher.write(secret.as_bytes());
+        hasher.write(b"easytier-256bit-key"); // 添加固定盐值以区分128位和256位密钥
+
+        // 生成32字节密钥
+        for i in 0..4 {
+            let chunk_start = i * 8;
+            let chunk_end = chunk_start + 8;
+            hasher.write(&key[0..chunk_start]);
+            hasher.write(&[i as u8]); // 添加索引以确保每个8字节块都不同
+            key[chunk_start..chunk_end].copy_from_slice(&hasher.finish().to_be_bytes());
+        }
+        key
+    }
+
     pub fn enable_exit_node(&self) -> bool {
         self.enable_exit_node
     }