Add 'X509CertificateUtils.getSubjectCommonName()'

1 files changed, 7 insertions, 1 deletions

diff --git a/security-utils/src/main/java/com/yahoo/security/X509CertificateUtils.java b/security-utils/src/main/java/com/yahoo/security/X509CertificateUtils.java
index f9f23ee1eb2..feb3b4df3e0 100644
--- a/security-utils/src/main/java/com/yahoo/security/X509CertificateUtils.java
+++ b/security-utils/src/main/java/com/yahoo/security/X509CertificateUtils.java
@@ -32,10 +32,10 @@ import java.security.cert.CertificateException;
 import java.security.cert.X509Certificate;
 import java.time.Duration;
 import java.time.Instant;
-import java.time.temporal.ChronoUnit;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Optional;
 import java.util.Random;
 
 import static com.yahoo.security.Extension.SUBJECT_ALTERNATIVE_NAMES;
@@ -115,6 +115,12 @@ public class X509CertificateUtils {
         return getCommonNames(certificate.getSubjectX500Principal());
     }
 
+    public static Optional<String> getSubjectCommonName(X509Certificate c) {
+        List<String> names = getSubjectCommonNames(c);
+        if (names.isEmpty()) return Optional.empty();
+        return Optional.of(names.get(names.size() - 1));
+    }
+
     public static List<String> getIssuerCommonNames(X509Certificate certificate) {
         return getCommonNames(certificate.getIssuerX500Principal());
     }