diff --git a/src/main/java/com/test/pgp/bc/BCPGPDecryptor.java b/src/main/java/com/test/pgp/bc/BCPGPDecryptor.java
index 3e5944c..d32f456 100644
--- a/src/main/java/com/test/pgp/bc/BCPGPDecryptor.java
+++ b/src/main/java/com/test/pgp/bc/BCPGPDecryptor.java
@@ -153,6 +153,9 @@ public InputStream decryptFile(InputStream in) throws Exception {
 			bytes = IOUtils.toByteArray(is);
 			
 			if (isSigned) {
+				if(ops == null){
+					throw new PGPException("Unsigned file, it's expected to be signed!");
+				}
 				ops.update(bytes);
 				PGPSignatureList p3 = (PGPSignatureList) pgpFact.nextObject();
 				if (!ops.verify(p3.get(0))) {
@@ -165,4 +168,4 @@ public InputStream decryptFile(InputStream in) throws Exception {
 		return new ByteArrayInputStream(bytes);
 	}
 
-}
\ No newline at end of file
+}