diff --git a/lib/libes/include/es/CertificateBody.h b/lib/libes/include/es/CertificateBody.h
index 2dd0cdb..37c3e48 100644
--- a/lib/libes/include/es/CertificateBody.h
+++ b/lib/libes/include/es/CertificateBody.h
@@ -17,7 +17,7 @@ namespace es
 		bool operator==(const CertificateBody& other) const;
 		bool operator!=(const CertificateBody& other) const;
 
-		void importBinary(byte_t* src, size_t size);
+		void importBinary(const byte_t* src, size_t size);
 		void exportBinary();
 
 		const byte_t* getBytes() const;
diff --git a/lib/libes/include/es/SignatureBlock.h b/lib/libes/include/es/SignatureBlock.h
index 86ab6c8..dcd5acb 100644
--- a/lib/libes/include/es/SignatureBlock.h
+++ b/lib/libes/include/es/SignatureBlock.h
@@ -17,7 +17,7 @@ namespace es
 		bool operator==(const SignatureBlock& other) const;
 		bool operator!=(const SignatureBlock& other) const;
 
-		void importBinary(byte_t* src, size_t size);
+		void importBinary(const byte_t* src, size_t size);
 		void exportBinary();
 
 		const byte_t* getBytes() const;
diff --git a/lib/libes/source/CertificateBody.cpp b/lib/libes/source/CertificateBody.cpp
index 627720b..6dca809 100644
--- a/lib/libes/source/CertificateBody.cpp
+++ b/lib/libes/source/CertificateBody.cpp
@@ -25,7 +25,7 @@ bool es::CertificateBody::operator!=(const CertificateBody& other) const
 	return !(*this == other);
 }
 
-void es::CertificateBody::importBinary(byte_t* src, size_t size)
+void es::CertificateBody::importBinary(const byte_t* src, size_t size)
 {
 	clear();
 
diff --git a/lib/libes/source/SignatureBlock.cpp b/lib/libes/source/SignatureBlock.cpp
index d8d6fba..d79ba96 100644
--- a/lib/libes/source/SignatureBlock.cpp
+++ b/lib/libes/source/SignatureBlock.cpp
@@ -25,7 +25,7 @@ bool es::SignatureBlock::operator!=(const SignatureBlock& other) const
 	return !(*this == other);
 }
 
-void es::SignatureBlock::importBinary(byte_t* src, size_t size)
+void es::SignatureBlock::importBinary(const byte_t* src, size_t size)
 {
 	clear();