diff --git a/ndn-cpp/sha256-with-rsa-signature.cpp b/ndn-cpp/sha256-with-rsa-signature.cpp
index c2c933f..5862faa 100644
--- a/ndn-cpp/sha256-with-rsa-signature.cpp
+++ b/ndn-cpp/sha256-with-rsa-signature.cpp
@@ -22,19 +22,19 @@
 {
   signatureStruct.digestAlgorithmLength = digestAlgorithm_.size();
   if (digestAlgorithm_.size() > 0)
-    signatureStruct.digestAlgorithm = (unsigned char *)digestAlgorithm_.buf();
+    signatureStruct.digestAlgorithm = (uint8_t *)digestAlgorithm_.buf();
   else
     signatureStruct.digestAlgorithm = 0;
 
   signatureStruct.witnessLength = witness_.size();
   if (witness_.size() > 0)
-    signatureStruct.witness = (unsigned char *)witness_.buf();
+    signatureStruct.witness = (uint8_t *)witness_.buf();
   else
     signatureStruct.witness = 0;
 
   signatureStruct.signatureLength = signature_.size();
   if (signature_.size() > 0)
-    signatureStruct.signature = (unsigned char *)signature_.buf();
+    signatureStruct.signature = (uint8_t *)signature_.buf();
   else
     signatureStruct.signature = 0;