diff --git a/agent/agent.js b/agent/agent.js
index 695bf9e..4f794f0 100644
--- a/agent/agent.js
+++ b/agent/agent.js
@@ -66,8 +66,8 @@ function realityKey(keyId) {
   const priv = kp.privateKey.export({ format: 'jwk' });
   const pub = kp.publicKey.export({ format: 'jwk' });
   if (!priv.d || !pub.x) throw new Error('X25519 密钥生成失败');
-  // JWK 用 base64url，sing-box 要标准 base64，转换一下
-  const b64urlToB64 = (s) => s.replace(/-/g, '+').replace(/_/g, '/') + '='.repeat((4 - s.length % 4) % 4);
+  // JWK 用 base64url，sing-box 要标准 base64，用 Buffer 转
+  const b64urlToB64 = (s) => Buffer.from(s, 'base64url').toString('base64');
   keys[keyId] = { privateKey: b64urlToB64(priv.d), publicKey: b64urlToB64(pub.x), createdAt: new Date().toISOString() };
   saveKeys(keys);
   return keys[keyId];