diff --git a/scripts/prep.sh b/scripts/prep.sh
index 8dde3156..0654c9c9 100755
--- a/scripts/prep.sh
+++ b/scripts/prep.sh
@@ -1,10 +1,9 @@
 #!/bin/bash
 
-VERSION=https://github.com/dafny-lang/dafny/releases/download/v4.3.0/dafny-4.3.0-x64-ubuntu-20.04.zip
+VERSION=https://github.com/dafny-lang/dafny/archive/refs/tags/v4.3.0.zip
 
 wget $VERSION
 unzip `basename $VERSION` 
 
-cd dafny
-dotnet add package System.Security.Cryptography.Algorithms --version 4.3.1
-cd ..
\ No newline at end of file
+cd dafny-4.3.0
+make exe
\ No newline at end of file
diff --git a/src/interop/cs/DRandomCoin.cs b/src/interop/cs/DRandomCoin.cs
index 955f6983..144cd13f 100644
--- a/src/interop/cs/DRandomCoin.cs
+++ b/src/interop/cs/DRandomCoin.cs
@@ -3,7 +3,7 @@
 *  SPDX-License-Identifier: MIT
 *******************************************************************************/
 
-using System.Security.Cryptography.Algorithms;
+using System.Security.Cryptography;
 using System.Numerics;
 
 namespace Coin_mInterface {
diff --git a/src/interop/cs/DRandomUniformPowerOfTwo.cs b/src/interop/cs/DRandomUniformPowerOfTwo.cs
index f0c0e29f..0d3ccdaf 100644
--- a/src/interop/cs/DRandomUniformPowerOfTwo.cs
+++ b/src/interop/cs/DRandomUniformPowerOfTwo.cs
@@ -4,7 +4,7 @@
 *******************************************************************************/
 
 using System;
-using System.Security.Cryptography.Algorithms;
+using System.Security.Cryptography;
 using System.Numerics;
 
 namespace UniformPowerOfTwo_mImplementation {