diff --git a/acme4j-client/src/test/java/org/shredzone/acme4j/AuthorizationTest.java b/acme4j-client/src/test/java/org/shredzone/acme4j/AuthorizationTest.java
index 1f218a11..b3fec57e 100644
--- a/acme4j-client/src/test/java/org/shredzone/acme4j/AuthorizationTest.java
+++ b/acme4j-client/src/test/java/org/shredzone/acme4j/AuthorizationTest.java
@@ -68,7 +68,6 @@ public class AuthorizationTest {
      * combinations.
      */
     @Test
-    @SuppressWarnings("unchecked")
     public void testFindCombination() throws IOException {
         Authorization authorization = createChallengeAuthorization();
 
diff --git a/acme4j-utils/src/main/java/org/shredzone/acme4j/util/CertificateUtils.java b/acme4j-utils/src/main/java/org/shredzone/acme4j/util/CertificateUtils.java
index a2076959..359d9b9a 100644
--- a/acme4j-utils/src/main/java/org/shredzone/acme4j/util/CertificateUtils.java
+++ b/acme4j-utils/src/main/java/org/shredzone/acme4j/util/CertificateUtils.java
@@ -13,31 +13,18 @@
  */
 package org.shredzone.acme4j.util;
 
-import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStream;
 import java.io.OutputStreamWriter;
 import java.io.Writer;
-import java.math.BigInteger;
-import java.security.KeyPair;
 import java.security.cert.CertificateException;
 import java.security.cert.CertificateFactory;
 import java.security.cert.X509Certificate;
-import java.time.Duration;
-import java.time.Instant;
-import java.util.Date;
 
-import org.bouncycastle.asn1.x500.X500Name;
-import org.bouncycastle.asn1.x509.Extension;
-import org.bouncycastle.asn1.x509.GeneralName;
-import org.bouncycastle.asn1.x509.GeneralNames;
-import org.bouncycastle.cert.jcajce.JcaX509v3CertificateBuilder;
 import org.bouncycastle.openssl.PEMParser;
 import org.bouncycastle.openssl.jcajce.JcaPEMWriter;
-import org.bouncycastle.operator.OperatorCreationException;
-import org.bouncycastle.operator.jcajce.JcaContentSignerBuilder;
 import org.bouncycastle.pkcs.PKCS10CertificationRequest;
 import org.shredzone.acme4j.Certificate;
 
@@ -170,46 +157,4 @@ public final class CertificateUtils {
         }
     }
 
-    /**
-     * Creates a generic self-signed challenge {@link X509Certificate}. The certificate is
-     * valid for 7 days.
-     *
-     * @param keypair
-     *            A domain {@link KeyPair} to be used for the challenge
-     * @param subject
-     *            Subjects to create a certificate for
-     * @return Created certificate
-     */
-    private static X509Certificate createCertificate(KeyPair keypair, String... subject) throws IOException {
-        final long now = System.currentTimeMillis();
-        final String signatureAlg = "SHA256withRSA";
-
-        try {
-            X500Name issuer = new X500Name("CN=acme.invalid");
-            BigInteger serial = BigInteger.valueOf(now);
-            Instant notBefore = Instant.ofEpochMilli(now);
-            Instant notAfter = notBefore.plus(Duration.ofDays(7));
-
-            JcaX509v3CertificateBuilder certBuilder = new JcaX509v3CertificateBuilder(
-                        issuer, serial, Date.from(notBefore), Date.from(notAfter),
-                        issuer, keypair.getPublic());
-
-            GeneralName[] gns = new GeneralName[subject.length];
-            for (int ix = 0; ix < subject.length; ix++) {
-                gns[ix] = new GeneralName(GeneralName.dNSName, subject[ix]);
-            }
-
-            certBuilder.addExtension(Extension.subjectAlternativeName, false, new GeneralNames(gns));
-
-            JcaContentSignerBuilder signerBuilder = new JcaContentSignerBuilder(signatureAlg);
-
-            byte[] cert = certBuilder.build(signerBuilder.build(keypair.getPrivate())).getEncoded();
-
-            CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
-            return (X509Certificate) certificateFactory.generateCertificate(new ByteArrayInputStream(cert));
-        } catch (CertificateException | OperatorCreationException ex) {
-            throw new IOException(ex);
-        }
-    }
-
 }
diff --git a/acme4j-utils/src/test/java/org/shredzone/acme4j/util/CertificateUtilsTest.java b/acme4j-utils/src/test/java/org/shredzone/acme4j/util/CertificateUtilsTest.java
index d007e789..223bb80b 100644
--- a/acme4j-utils/src/test/java/org/shredzone/acme4j/util/CertificateUtilsTest.java
+++ b/acme4j-utils/src/test/java/org/shredzone/acme4j/util/CertificateUtilsTest.java
@@ -26,13 +26,8 @@ import java.lang.reflect.Modifier;
 import java.security.KeyPair;
 import java.security.cert.CertificateException;
 import java.security.cert.CertificateFactory;
-import java.security.cert.CertificateParsingException;
 import java.security.cert.X509Certificate;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
 
-import org.bouncycastle.asn1.x509.GeneralName;
 import org.bouncycastle.pkcs.PKCS10CertificationRequest;
 import org.junit.Before;
 import org.junit.Test;
@@ -204,23 +199,4 @@ public class CertificateUtilsTest {
         return count;
     }
 
-    /**
-     * Extracts all DNSName SANs from a certificate.
-     *
-     * @param cert
-     *            {@link X509Certificate}
-     * @return Set of DNSName
-     */
-    private Set<String> getSANs(X509Certificate cert) throws CertificateParsingException {
-        Set<String> result = new HashSet<>();
-
-        for (List<?> list : cert.getSubjectAlternativeNames()) {
-            if (((Number) list.get(0)).intValue() == GeneralName.dNSName) {
-                result.add((String) list.get(1));
-            }
-        }
-
-        return result;
-    }
-
 }