2 files changed, 2 insertions, 4 deletions
diff --git a/crypto/src/pkix/PkixCertPathChecker.cs b/crypto/src/pkix/PkixCertPathChecker.cs
index f22738d89..da7e82b46 100644
--- a/crypto/src/pkix/PkixCertPathChecker.cs
+++ b/crypto/src/pkix/PkixCertPathChecker.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Collections;
 using Org.BouncyCastle.Utilities.Collections;
 using Org.BouncyCastle.X509;
 
@@ -82,7 +80,7 @@ namespace Org.BouncyCastle.Pkix
          * @exception CertPathValidatorException
          *                if the specified certificate does not pass the check
          */
-        public abstract void Check(X509Certificate cert, ICollection unresolvedCritExts);
+        public abstract void Check(X509Certificate cert, ISet unresolvedCritExts);
         //throws CertPathValidatorException;
 
         /**
diff --git a/crypto/test/src/test/CertPathValidatorTest.cs b/crypto/test/src/test/CertPathValidatorTest.cs
index a92bb9b31..f83ac850a 100644
--- a/crypto/test/src/test/CertPathValidatorTest.cs
+++ b/crypto/test/src/test/CertPathValidatorTest.cs
@@ -290,7 +290,7 @@ namespace Org.BouncyCastle.Tests
                 return null;
             }
 
-            public override void Check(X509Certificate cert, ICollection unresolvedCritExts)
+            public override void Check(X509Certificate cert, ISet unresolvedCritExts)
             {
                 count++;
             }