diff --git a/xcode/OLMKit/OLMInboundGroupSession.m b/xcode/OLMKit/OLMInboundGroupSession.m
index 4f7bdd7..6ef51c3 100644
--- a/xcode/OLMKit/OLMInboundGroupSession.m
+++ b/xcode/OLMKit/OLMInboundGroupSession.m
@@ -143,6 +143,7 @@
     }
     plaintextData.length = plaintextLength;
     NSString *plaintext = [[NSString alloc] initWithData:plaintextData encoding:NSUTF8StringEncoding];
+    [plaintextData resetBytesInRange:NSMakeRange(0, plaintextData.length)];
 
     if (messageIndex)
     {
diff --git a/xcode/OLMKit/OLMSession.m b/xcode/OLMKit/OLMSession.m
index 2111c1c..8c29113 100644
--- a/xcode/OLMKit/OLMSession.m
+++ b/xcode/OLMKit/OLMSession.m
@@ -287,6 +287,7 @@
     }
     plaintextData.length = plaintextLength;
     NSString *plaintext = [[NSString alloc] initWithData:plaintextData encoding:NSUTF8StringEncoding];
+    [plaintextData resetBytesInRange:NSMakeRange(0, plaintextData.length)];
     return plaintext;
 }