diff --git a/lib/crypto.js b/lib/crypto.js
index 95daf2f..1235ba6 100644
--- a/lib/crypto.js
+++ b/lib/crypto.js
@@ -106,10 +106,8 @@ var encrypted = exports.encrypted = {
     assert(buf.readUInt16BE(52, true) === 32, "Bad Ry length");
     var iv = new Buffer(16);
     buf.copy(iv, 0, 0, 16);
-    var ephemPublicKey = new Buffer(65);
-    ephemPublicKey[0] = 0x04;
-    buf.copy(ephemPublicKey, 1, 20, 52);
-    buf.copy(ephemPublicKey, 33, 54, 86);
+    var ephemPublicKey = new Buffer(70);
+    buf.copy(ephemPublicKey, 0, 16, 86);
     // NOTE(Kagami): We do copy instead of slice to protect against
     // possible source buffer modification by user.
     var ciphertext = new Buffer(buf.length - 118);
@@ -126,19 +124,13 @@ var encrypted = exports.encrypted = {
 
   encode: function(opts) {
     assert(opts.iv.length === 16, "Bad IV");
-    assert(opts.ephemPublicKey.length === 65, "Bad public key");
+    assert(opts.ephemPublicKey.length === 70, "Bad public key");
+    assert(
+      opts.ephemPublicKey.readUInt16BE(0, true) === SECP256K1_TYPE,
+      "Bad curve type");
     assert(opts.mac.length === 32, "Bad MAC");
-    // 16 + 2 + 2 + 32 + 2 + 32 + ? + 32
-    var buf = new Buffer(118 + opts.ciphertext.length);
-    opts.iv.copy(buf);
-    buf.writeUInt16BE(SECP256K1_TYPE, 16, true);  // Curve type
-    buf.writeUInt16BE(32, 18, true);  // Rx length
-    opts.ephemPublicKey.copy(buf, 20, 1, 33);  // Rx
-    buf.writeUInt16BE(32, 52, true);  // Ry length
-    opts.ephemPublicKey.copy(buf, 54, 33);  // Ry
-    opts.ciphertext.copy(buf, 86);
-    opts.mac.copy(buf, 86 + opts.ciphertext.length);
-    return buf;
+    return Buffer.concat(
+      [opts.iv, opts.ephemPublicKey, opts.ciphertext, opts.mac]);
   },
 };