Implement data structures from X.680, X.501, X.509, and PKCS#10, with X.690 encoding / decoding support

The implementation took four days, and it is still a little bit rough. Updated version should arrive soon.

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

1 files changed, 67 insertions, 0 deletions

diff --git a/src/main/model/pki/cert/Extensions.java b/src/main/model/pki/cert/Extensions.java
new file mode 100644
index 0000000..780fa2c
--- /dev/null
+++ b/src/main/model/pki/cert/Extensions.java
@@ -0,0 +1,67 @@
+package model.pki.cert;
+
+import model.asn1.ASN1Object;
+import model.asn1.Encodable;
+import model.asn1.Tag;
+import model.asn1.exceptions.ParseException;
+import model.asn1.parsing.BytesReader;
+import model.x501.RelativeDistinguishedName;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Stream;
+
+/**
+ * Represents an X.509 certificate extensions list:
+ * <pre>
+ *     Extensions ::= SEQUENCE OF Extension
+ * </pre>
+ */
+public class Extensions extends ASN1Object {
+    private final Extension[] extensions;
+
+    /**
+     * EFFECT: Initialize with the given tags and extensions. For tag and parentTag, consult
+     * {@link ASN1Object}.
+     * REQUIRES: Extensions should have SEQUENCE tag.
+     */
+    public Extensions(Tag tag, Tag parentTag, Extension[] extensions) {
+        super(tag, parentTag);
+        this.extensions = extensions;
+    }
+
+    /**
+     * EFFECT: Parse the Name from input DER bytes. For details on parsing, refer to {@link ASN1Object}.
+     *   Throws {@link ParseException} for invalid input.
+     * MODIFIES: this, encoded
+     */
+    public Extensions(BytesReader encoded, boolean hasParentTag) throws ParseException {
+        super(encoded, hasParentTag);
+        final List<Extension> list = new ArrayList<>();
+        for (int i = 0; i < getLength();) {
+            int index = encoded.getIndex();
+            final Extension ext = new Extension(encoded, false);
+            ext.getTag().enforce(TAG_SEQUENCE);
+            list.add(ext);
+            index = encoded.getIndex() - index;
+            i += index;
+        }
+        this.extensions = list.toArray(new Extension[0]);
+    }
+
+    /**
+     * EFFECTS: Encode the SEQUENCE OF into DER, keep order. RDNs will be encoded one-by-one.
+     */
+    @Override
+    public Byte[] encodeValueDER() {
+        return Stream.of(extensions)
+                .map(Encodable::encodeDER)
+                .flatMap(Arrays::stream)
+                .toArray(Byte[]::new);
+    }
+
+    public Extension[] getExtensions() {
+        return extensions;
+    }
+}