diff --git a/src/SignatureKeyPair.php b/src/SignatureKeyPair.php
index 1dd4890..81980be 100644
--- a/src/SignatureKeyPair.php
+++ b/src/SignatureKeyPair.php
@@ -120,6 +120,19 @@ public function __construct(Key ...$keys)
         }
     }
 
+    /**
+     * @return EncryptionKeyPair
+     * @throws InvalidKey
+     * @throws \TypeError
+     */
+    public function getEncryptionKeyPair(): EncryptionKeyPair
+    {
+        return new EncryptionKeyPair(
+            $this->secretKey->getEncryptionSecretKey(),
+            $this->publicKey->getEncryptionPublicKey()
+        );
+    }
+
     /**
      * Set up our key pair
      *
diff --git a/test/unit/KeyPairTest.php b/test/unit/KeyPairTest.php
index 3c5eaaf..b34ff93 100644
--- a/test/unit/KeyPairTest.php
+++ b/test/unit/KeyPairTest.php
@@ -236,6 +236,7 @@ public function testFileStorage()
     public function testMutation()
     {
         $sign_kp = KeyFactory::generateSignatureKeyPair();
+        $box_kp = $sign_kp->getEncryptionKeyPair();
         $sign_sk = $sign_kp->getSecretKey();
         $sign_pk = $sign_kp->getPublicKey();
 
@@ -245,6 +246,10 @@ public function testMutation()
             Hex::encode($enc_pk->getRawKeyMaterial()),
             Hex::encode($enc_sk->derivePublicKey()->getRawKeyMaterial())
         );
+        $this->assertSame(
+            Hex::encode($enc_sk->getRawKeyMaterial()),
+            Hex::encode($box_kp->getSecretKey()->getRawKeyMaterial())
+        );
     }
 
     /**