diff --git a/cli/src/native/auth.rs b/cli/src/native/auth.rs
index db60ed6..f130585 100644
--- a/cli/src/native/auth.rs
+++ b/cli/src/native/auth.rs
@@ -1,11 +1,12 @@
 use aes_gcm::{aead::Aead, aead::KeyInit, Aes256Gcm};
+use base64::{engine::general_purpose::STANDARD, Engine};
 use serde::{Deserialize, Serialize};
 use serde_json::{json, Value};
-use sha2::{Digest, Sha256};
 use std::fs;
 use std::path::PathBuf;
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
 pub struct AuthProfile {
     pub name: String,
     pub url: String,
@@ -17,6 +18,10 @@ pub struct AuthProfile {
     pub password_selector: Option<String>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub submit_selector: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub created_at: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub last_login_at: Option<String>,
 }
 
 // Keep legacy Credential alias for backward compatibility
@@ -48,79 +53,203 @@ fn get_profile_path(name: &str) -> PathBuf {
     get_auth_dir().join(format!("{}.json", name))
 }
 
-fn derive_encryption_key() -> Vec<u8> {
-    let hostname = std::env::var("HOSTNAME")
-        .or_else(|_| std::env::var("COMPUTERNAME"))
-        .unwrap_or_else(|_| {
-            #[cfg(unix)]
-            {
-                let mut buf = [0u8; 256];
-                let len = unsafe { libc::gethostname(buf.as_mut_ptr() as *mut _, buf.len()) };
-                if len == 0 {
-                    let end = buf.iter().position(|&b| b == 0).unwrap_or(buf.len());
-                    String::from_utf8_lossy(&buf[..end]).to_string()
-                } else {
-                    "unknown-host".to_string()
-                }
-            }
-            #[cfg(not(unix))]
-            {
-                "unknown-host".to_string()
-            }
-        });
-    let username = std::env::var("USER")
-        .or_else(|_| std::env::var("USERNAME"))
-        .unwrap_or_else(|_| "unknown-user".to_string());
-    let mut hasher = Sha256::new();
-    hasher.update(format!("agent-browser:{}:{}", hostname, username).as_bytes());
-    hasher.finalize().to_vec()
+const ENCRYPTION_KEY_ENV: &str = "AGENT_BROWSER_ENCRYPTION_KEY";
+const KEY_FILE_NAME: &str = ".encryption-key";
+
+fn get_agent_browser_dir() -> PathBuf {
+    if let Some(home) = dirs::home_dir() {
+        home.join(".agent-browser")
+    } else {
+        std::env::temp_dir().join("agent-browser")
+    }
 }
 
-fn encrypt_profile(profile: &AuthProfile) -> Result<Vec<u8>, String> {
-    let key = derive_encryption_key();
+fn get_key_file_path() -> PathBuf {
+    get_agent_browser_dir().join(KEY_FILE_NAME)
+}
+
+fn parse_key_hex(hex_str: &str) -> Option<Vec<u8>> {
+    let hex_str = hex_str.trim();
+    if hex_str.len() != 64 || !hex_str.chars().all(|c| c.is_ascii_hexdigit()) {
+        return None;
+    }
+    let bytes: Vec<u8> = (0..32)
+        .map(|i| u8::from_str_radix(&hex_str[i * 2..i * 2 + 2], 16).unwrap())
+        .collect();
+    Some(bytes)
+}
+
+/// Read the encryption key from AGENT_BROWSER_ENCRYPTION_KEY env var or
+/// ~/.agent-browser/.encryption-key file (matching the Node.js implementation).
+fn get_encryption_key() -> Result<Vec<u8>, String> {
+    if let Ok(key_hex) = std::env::var(ENCRYPTION_KEY_ENV) {
+        return parse_key_hex(&key_hex).ok_or_else(|| {
+            format!(
+                "{} should be a 64-character hex string (256 bits). Generate one with: openssl rand -hex 32",
+                ENCRYPTION_KEY_ENV
+            )
+        });
+    }
+
+    let key_file = get_key_file_path();
+    if key_file.exists() {
+        let hex = fs::read_to_string(&key_file)
+            .map_err(|e| format!("Failed to read encryption key file: {}", e))?;
+        return parse_key_hex(&hex).ok_or_else(|| {
+            format!(
+                "Invalid encryption key in {}. Expected 64-character hex string.",
+                key_file.display()
+            )
+        });
+    }
+
+    Err(format!(
+        "Encryption key required. Set {} or ensure {} exists.",
+        ENCRYPTION_KEY_ENV,
+        key_file.display()
+    ))
+}
+
+/// Ensure an encryption key exists, auto-generating one if needed.
+fn ensure_encryption_key() -> Result<Vec<u8>, String> {
+    if let Ok(key) = get_encryption_key() {
+        return Ok(key);
+    }
+
+    let mut key = [0u8; 32];
+    getrandom::getrandom(&mut key).map_err(|e| format!("Failed to generate key: {}", e))?;
+    let key_hex = key.iter().map(|b| format!("{:02x}", b)).collect::<String>();
+
+    let dir = get_agent_browser_dir();
+    fs::create_dir_all(&dir).map_err(|e| format!("Failed to create directory: {}", e))?;
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        let _ = fs::set_permissions(&dir, fs::Permissions::from_mode(0o700));
+    }
+
+    let key_file = get_key_file_path();
+    fs::write(&key_file, format!("{}\n", key_hex))
+        .map_err(|e| format!("Failed to write encryption key: {}", e))?;
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        let _ = fs::set_permissions(&key_file, fs::Permissions::from_mode(0o600));
+    }
+
+    eprintln!(
+        "[agent-browser] Auto-generated encryption key at {} -- back up this file or set {}",
+        key_file.display(),
+        ENCRYPTION_KEY_ENV
+    );
+
+    Ok(key.to_vec())
+}
+
+/// Encrypt a profile to the JSON+base64 format compatible with Node.js.
+fn encrypt_profile(profile: &AuthProfile) -> Result<String, String> {
+    let key = ensure_encryption_key()?;
     let cipher =
         Aes256Gcm::new_from_slice(&key).map_err(|e| format!("Encryption key error: {}", e))?;
 
     let plaintext = serde_json::to_string(profile)
         .map_err(|e| format!("Failed to serialize profile: {}", e))?;
 
-    let mut nonce = [0u8; 12];
-    getrandom::getrandom(&mut nonce).map_err(|e| format!("Failed to generate nonce: {}", e))?;
-    let ciphertext = cipher
-        .encrypt(aes_gcm::Nonce::from_slice(&nonce), plaintext.as_bytes())
+    let mut iv = [0u8; 12];
+    getrandom::getrandom(&mut iv).map_err(|e| format!("Failed to generate IV: {}", e))?;
+
+    // aes_gcm appends the 16-byte auth tag to the ciphertext
+    let encrypted = cipher
+        .encrypt(aes_gcm::Nonce::from_slice(&iv), plaintext.as_bytes())
         .map_err(|e| format!("Encryption failed: {}", e))?;
 
-    let mut result = Vec::with_capacity(12 + ciphertext.len());
-    result.extend_from_slice(&nonce);
-    result.extend_from_slice(&ciphertext);
-    Ok(result)
+    let tag_offset = encrypted.len() - 16;
+    let ciphertext = &encrypted[..tag_offset];
+    let auth_tag = &encrypted[tag_offset..];
+
+    let payload = json!({
+        "version": 1,
+        "encrypted": true,
+        "iv": STANDARD.encode(iv),
+        "authTag": STANDARD.encode(auth_tag),
+        "data": STANDARD.encode(ciphertext),
+    });
+
+    serde_json::to_string_pretty(&payload)
+        .map_err(|e| format!("Failed to serialize payload: {}", e))
+}
+
+/// JSON envelope written by Node.js encryption (src/encryption.ts).
+#[derive(Deserialize)]
+struct EncryptedPayload {
+    #[allow(dead_code)]
+    version: u32,
+    #[allow(dead_code)]
+    encrypted: bool,
+    iv: String,
+    #[serde(rename = "authTag")]
+    auth_tag: String,
+    data: String,
 }
 
 fn decrypt_profile(data: &[u8]) -> Result<AuthProfile, String> {
-    if data.len() < 13 {
-        return Err("Encrypted data too short".to_string());
+    let text = std::str::from_utf8(data).map_err(|_| {
+        "Profile is not valid UTF-8 -- it may use an older incompatible binary format".to_string()
+    })?;
+
+    if let Ok(payload) = serde_json::from_str::<EncryptedPayload>(text) {
+        let key = get_encryption_key()?;
+
+        let iv = STANDARD
+            .decode(&payload.iv)
+            .map_err(|e| format!("Invalid base64 iv: {}", e))?;
+        let auth_tag = STANDARD
+            .decode(&payload.auth_tag)
+            .map_err(|e| format!("Invalid base64 authTag: {}", e))?;
+        let ciphertext = STANDARD
+            .decode(&payload.data)
+            .map_err(|e| format!("Invalid base64 data: {}", e))?;
+
+        // aes_gcm expects ciphertext || auth_tag as input to decrypt
+        let mut combined = Vec::with_capacity(ciphertext.len() + auth_tag.len());
+        combined.extend_from_slice(&ciphertext);
+        combined.extend_from_slice(&auth_tag);
+
+        let cipher = Aes256Gcm::new_from_slice(&key)
+            .map_err(|e| format!("Decryption key error: {}", e))?;
+        let plaintext = cipher
+            .decrypt(aes_gcm::Nonce::from_slice(&iv), combined.as_slice())
+            .map_err(|e| format!("Decryption failed: {}", e))?;
+
+        let json_str = String::from_utf8(plaintext)
+            .map_err(|e| format!("Decrypted data is not valid UTF-8: {}", e))?;
+        return serde_json::from_str(&json_str)
+            .map_err(|e| format!("Invalid profile data: {}", e));
     }
-    let (nonce_bytes, ciphertext) = data.split_at(12);
 
-    let key = derive_encryption_key();
-    let cipher =
-        Aes256Gcm::new_from_slice(&key).map_err(|e| format!("Decryption key error: {}", e))?;
-    let plaintext = cipher
-        .decrypt(aes_gcm::Nonce::from_slice(nonce_bytes), ciphertext)
-        .map_err(|e| format!("Decryption failed: {}", e))?;
-
-    let json_str = String::from_utf8(plaintext)
-        .map_err(|e| format!("Decrypted data is not valid UTF-8: {}", e))?;
-    serde_json::from_str(&json_str).map_err(|e| format!("Invalid profile data: {}", e))
+    // Fallback: try as plain unencrypted JSON profile
+    serde_json::from_str::<AuthProfile>(text)
+        .map_err(|_| "Profile is not a valid encrypted or unencrypted payload".to_string())
 }
 
 fn save_profile(profile: &AuthProfile) -> Result<(), String> {
     let dir = get_auth_dir();
-    let _ = fs::create_dir_all(&dir);
+    fs::create_dir_all(&dir).map_err(|e| format!("Failed to create auth dir: {}", e))?;
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        let _ = fs::set_permissions(&dir, fs::Permissions::from_mode(0o700));
+    }
 
-    let encrypted = encrypt_profile(profile)?;
+    let encrypted_json = encrypt_profile(profile)?;
     let path = get_profile_path(&profile.name);
-    fs::write(&path, &encrypted).map_err(|e| format!("Failed to write profile: {}", e))
+    fs::write(&path, &encrypted_json).map_err(|e| format!("Failed to write profile: {}", e))?;
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        let _ = fs::set_permissions(&path, fs::Permissions::from_mode(0o600));
+    }
+    Ok(())
 }
 
 fn load_profile(name: &str) -> Result<AuthProfile, String> {
@@ -147,6 +276,8 @@ pub fn credentials_set(
         username_selector: None,
         password_selector: None,
         submit_selector: None,
+        created_at: None,
+        last_login_at: None,
     };
     save_profile(&profile)?;
     Ok(json!({ "saved": name }))
@@ -170,6 +301,8 @@ pub fn auth_save(
         username_selector: username_selector.map(String::from),
         password_selector: password_selector.map(String::from),
         submit_selector: submit_selector.map(String::from),
+        created_at: None,
+        last_login_at: None,
     };
     save_profile(&profile)?;
     Ok(json!({ "saved": name }))
@@ -252,10 +385,27 @@ pub fn auth_show(name: &str) -> Result<Value, String> {
     }))
 }
 
+#[cfg(test)]
+pub(crate) static AUTH_TEST_MUTEX: std::sync::Mutex<()> = std::sync::Mutex::new(());
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
+    fn with_test_key<F: FnOnce()>(f: F) {
+        let _lock = AUTH_TEST_MUTEX.lock().unwrap();
+        let original = std::env::var(ENCRYPTION_KEY_ENV).ok();
+        let test_key = "a".repeat(64);
+        // SAFETY: TEST_MUTEX serializes all test access so no concurrent mutation.
+        unsafe { std::env::set_var(ENCRYPTION_KEY_ENV, &test_key) };
+        f();
+        // SAFETY: TEST_MUTEX serializes all test access so no concurrent mutation.
+        match original {
+            Some(val) => unsafe { std::env::set_var(ENCRYPTION_KEY_ENV, val) },
+            None => unsafe { std::env::remove_var(ENCRYPTION_KEY_ENV) },
+        }
+    }
+
     #[test]
     fn test_validate_profile_name() {
         assert!(validate_profile_name("github").is_ok());
@@ -277,6 +427,8 @@ mod tests {
             username_selector: None,
             password_selector: None,
             submit_selector: Some("button[type=submit]".to_string()),
+            created_at: None,
+            last_login_at: None,
         };
         let json = serde_json::to_string(&profile).unwrap();
         let parsed: AuthProfile = serde_json::from_str(&json).unwrap();
@@ -290,26 +442,114 @@ mod tests {
 
     #[test]
     fn test_encrypt_decrypt_roundtrip() {
-        let profile = AuthProfile {
-            name: "roundtrip".to_string(),
-            url: "https://example.com".to_string(),
-            username: "user".to_string(),
-            password: "s3cret!".to_string(),
-            username_selector: None,
-            password_selector: None,
-            submit_selector: None,
-        };
-        let encrypted = encrypt_profile(&profile).unwrap();
-        let decrypted = decrypt_profile(&encrypted).unwrap();
-        assert_eq!(decrypted.name, "roundtrip");
-        assert_eq!(decrypted.password, "s3cret!");
+        with_test_key(|| {
+            let profile = AuthProfile {
+                name: "roundtrip".to_string(),
+                url: "https://example.com".to_string(),
+                username: "user".to_string(),
+                password: "s3cret!".to_string(),
+                username_selector: None,
+                password_selector: None,
+                submit_selector: None,
+                created_at: None,
+                last_login_at: None,
+            };
+            let encrypted_json = encrypt_profile(&profile).unwrap();
+            let decrypted = decrypt_profile(encrypted_json.as_bytes()).unwrap();
+            assert_eq!(decrypted.name, "roundtrip");
+            assert_eq!(decrypted.password, "s3cret!");
+        });
     }
 
     #[test]
-    fn test_derive_encryption_key_is_stable() {
-        let k1 = derive_encryption_key();
-        let k2 = derive_encryption_key();
-        assert_eq!(k1, k2);
-        assert_eq!(k1.len(), 32);
+    fn test_get_encryption_key_from_env() {
+        with_test_key(|| {
+            let key = get_encryption_key().unwrap();
+            assert_eq!(key.len(), 32);
+            assert!(key.iter().all(|&b| b == 0xaa));
+        });
+    }
+
+    #[test]
+    fn test_parse_key_hex_valid() {
+        let hex = "ab".repeat(32);
+        let key = parse_key_hex(&hex).unwrap();
+        assert_eq!(key.len(), 32);
+        assert!(key.iter().all(|&b| b == 0xab));
+    }
+
+    #[test]
+    fn test_parse_key_hex_invalid() {
+        assert!(parse_key_hex("too_short").is_none());
+        assert!(parse_key_hex(&"g".repeat(64)).is_none());
+        assert!(parse_key_hex("").is_none());
+    }
+
+    #[test]
+    fn test_decrypt_json_payload_format() {
+        with_test_key(|| {
+            let key = get_encryption_key().unwrap();
+            let profile = AuthProfile {
+                name: "json-test".to_string(),
+                url: "https://example.com/login".to_string(),
+                username: "admin".to_string(),
+                password: "hunter2".to_string(),
+                username_selector: Some("#email".to_string()),
+                password_selector: None,
+                submit_selector: None,
+                created_at: None,
+                last_login_at: None,
+            };
+
+            // Encrypt with aes_gcm, then manually build the JSON payload
+            // to simulate what Node.js would produce
+            let cipher = Aes256Gcm::new_from_slice(&key).unwrap();
+            let mut iv = [0u8; 12];
+            getrandom::getrandom(&mut iv).unwrap();
+            let plaintext = serde_json::to_string(&profile).unwrap();
+            let encrypted = cipher
+                .encrypt(aes_gcm::Nonce::from_slice(&iv), plaintext.as_bytes())
+                .unwrap();
+
+            let tag_offset = encrypted.len() - 16;
+            let ciphertext = &encrypted[..tag_offset];
+            let auth_tag = &encrypted[tag_offset..];
+
+            let payload = format!(
+                r#"{{"version":1,"encrypted":true,"iv":"{}","authTag":"{}","data":"{}"}}"#,
+                STANDARD.encode(iv),
+                STANDARD.encode(auth_tag),
+                STANDARD.encode(ciphertext),
+            );
+
+            let decrypted = decrypt_profile(payload.as_bytes()).unwrap();
+            assert_eq!(decrypted.name, "json-test");
+            assert_eq!(decrypted.password, "hunter2");
+            assert_eq!(decrypted.username_selector, Some("#email".to_string()));
+        });
+    }
+
+    #[test]
+    fn test_encrypted_output_is_json_format() {
+        with_test_key(|| {
+            let profile = AuthProfile {
+                name: "format-check".to_string(),
+                url: "https://example.com".to_string(),
+                username: "user".to_string(),
+                password: "pass".to_string(),
+                username_selector: None,
+                password_selector: None,
+                submit_selector: None,
+                created_at: None,
+                last_login_at: None,
+            };
+            let encrypted = encrypt_profile(&profile).unwrap();
+            let parsed: Value = serde_json::from_str(&encrypted).unwrap();
+            assert_eq!(parsed["version"], 1);
+            assert_eq!(parsed["encrypted"], true);
+            assert!(parsed["iv"].is_string());
+            assert!(parsed["authTag"].is_string());
+            assert!(parsed["data"].is_string());
+        });
     }
 }
diff --git a/cli/src/native/parity_tests.rs b/cli/src/native/parity_tests.rs
index 4a1f7cf..b773a38 100644
--- a/cli/src/native/parity_tests.rs
+++ b/cli/src/native/parity_tests.rs
@@ -9,6 +9,38 @@ use serde_json::{json, Value};
 
 use super::actions::{execute_command, DaemonState};
 
+const ENCRYPTION_KEY_ENV: &str = "AGENT_BROWSER_ENCRYPTION_KEY";
+
+struct TestKeyGuard {
+    _lock: std::sync::MutexGuard<'static, ()>,
+    original: Option<String>,
+}
+
+impl TestKeyGuard {
+    fn new() -> Self {
+        let lock = super::auth::AUTH_TEST_MUTEX
+            .lock()
+            .unwrap_or_else(|e| e.into_inner());
+        let original = std::env::var(ENCRYPTION_KEY_ENV).ok();
+        // SAFETY: AUTH_TEST_MUTEX serializes all test access so no concurrent mutation.
+        unsafe { std::env::set_var(ENCRYPTION_KEY_ENV, "a".repeat(64)) };
+        Self {
+            _lock: lock,
+            original,
+        }
+    }
+}
+
+impl Drop for TestKeyGuard {
+    fn drop(&mut self) {
+        // SAFETY: AUTH_TEST_MUTEX is held via _lock.
+        match &self.original {
+            Some(val) => unsafe { std::env::set_var(ENCRYPTION_KEY_ENV, val) },
+            None => unsafe { std::env::remove_var(ENCRYPTION_KEY_ENV) },
+        }
+    }
+}
+
 /// All documented action names that should be implemented.
 const DOCUMENTED_ACTIONS: &[&str] = &[
     "launch",
@@ -424,6 +456,7 @@ async fn test_credentials_list_without_browser() {
 #[tokio::test]
 async fn test_auth_profile_name_validation() {
     use super::auth;
+    let _key_guard = TestKeyGuard::new();
     let valid = auth::credentials_set("valid-name_123", "u", "p", None);
     assert!(valid.is_ok());
     let invalid = auth::credentials_set("invalid/name", "u", "p", None);
@@ -439,6 +472,7 @@ async fn test_auth_profile_name_validation() {
 #[tokio::test]
 async fn test_auth_save_and_show() {
     use super::auth;
+    let _key_guard = TestKeyGuard::new();
     let result = auth::auth_save(
         "parity-roundtrip",
         "https://example.com",