1 files changed, 4 insertions, 0 deletions
diff --git a/crypto/src/crypto/engines/IesEngine.cs b/crypto/src/crypto/engines/IesEngine.cs
index a2004a9d6..9139f3ffc 100644
--- a/crypto/src/crypto/engines/IesEngine.cs
+++ b/crypto/src/crypto/engines/IesEngine.cs
@@ -97,6 +97,10 @@ namespace Org.BouncyCastle.Crypto.Engines
 
             kdf.Init(kParam);
 
+            // Ensure that the length of the input is greater than the MAC in bytes
+            if (inLen <= mac.GetMacSize())
+                throw new InvalidCipherTextException("Length of input must be greater than the MAC");
+
             inLen -= mac.GetMacSize();
 
             if (cipher == null)     // stream mode