Implement the CA

Signed-off-by: Yuuta Liang <yuutaw@students.cs.ubc.ca>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/main/model/pki/cert/TbsCertificate.java b/src/main/model/pki/cert/TbsCertificate.java
index 1175456..ce228af 100644
--- a/src/main/model/pki/cert/TbsCertificate.java
+++ b/src/main/model/pki/cert/TbsCertificate.java
@@ -229,6 +229,21 @@ public class TbsCertificate extends ASN1Object {
                 .toArray(Byte[]::new);
     }
 
+    /**
+     * EFFECT: Get the extension by ID. If the certificate is V1 or does not have any extensions or does not have the
+     * specified extension, null is returned.
+     * REQUIRES: extnId should be a valid X.509 certificate extension ID.
+     */
+    public Extension getExtension(Integer[] extnId) {
+        if (extensions == null) {
+            return null;
+        }
+        return Arrays.stream(extensions.getExtensions())
+                .filter(extn -> Arrays.equals(extnId, extn.getExtnId().getInts()))
+                .findFirst()
+                .orElse(null);
+    }
+
     public Int getVersion() {
         return version;
     }