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, 95 insertions, 0 deletions

diff --git a/src/main/model/pki/cert/Validity.java b/src/main/model/pki/cert/Validity.java
new file mode 100644
index 0000000..76279ed
--- /dev/null
+++ b/src/main/model/pki/cert/Validity.java
@@ -0,0 +1,95 @@
+package model.pki.cert;
+
+import model.asn1.*;
+import model.asn1.exceptions.ParseException;
+import model.asn1.parsing.BytesReader;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.stream.Stream;
+
+/**
+ * Represents the following ASN.1 structure:
+ * <pre>
+ *     Validity ::= SEQUENCE {
+ *         notBefore Time,
+ *         notAfter Time,
+ *         ...
+ *     }
+ *
+ *     Time ::= CHOICE {
+ *         utcTime UTCTime,
+ *         generalizedTime GeneralizedTime
+ *     }
+ * </pre>
+ * It describes the validity period of the certificate.
+ */
+public class Validity extends ASN1Object {
+    /**
+     * The certificate is not valid before that time.
+     */
+    private final ASN1Time notBefore;
+
+    /**
+     * The certificate is not valid after that time.
+     */
+    private final ASN1Time notAfter;
+
+    /**
+     * EFFECTS: Init with the given tag, parentTag, notBefore, and notAfter. For more info on tag and parentTag, see
+     * {@link ASN1Object}.
+     * REQUIRES: notBefore and notAfter are either UTCTime or GeneralizedTime.
+     */
+    public Validity(Tag tag, Tag parentTag,
+                    ASN1Time notBefore, ASN1Time notAfter) {
+        super(tag, parentTag);
+        this.notBefore = notBefore;
+        this.notAfter = notAfter;
+    }
+
+    /**
+     * EFFECTS: Parse input DER.
+     *   Throws {@link ASN1Object} if invalid:
+     *    - Any fields missing (info, algorithm, signature)
+     *    - Any fields having an incorrect tag (as seen in the ASN.1 definition)
+     *    - Any fields with encoding instructions that violate implicit / explicit encoding rules
+     *    - Other issues found during parsing the object, like early EOF (see {@link ASN1Object})
+     * MODIFIES: this, encoded
+     */
+    public Validity(BytesReader encoded, boolean hasParentTag) throws ParseException {
+        super(encoded, hasParentTag);
+        if (encoded.detectTag(GeneralizedTime.TAG)) {
+            this.notBefore = new GeneralizedTime(encoded, false);
+            this.notBefore.getTag().enforce(GeneralizedTime.TAG);
+        } else {
+            this.notBefore = new UtcTime(encoded, false);
+            this.notBefore.getTag().enforce(UtcTime.TAG);
+        }
+        if (encoded.detectTag(GeneralizedTime.TAG)) {
+            this.notAfter = new GeneralizedTime(encoded, false);
+            this.notAfter.getTag().enforce(GeneralizedTime.TAG);
+        } else {
+            this.notAfter = new UtcTime(encoded, false);
+            this.notAfter.getTag().enforce(UtcTime.TAG);
+        }
+    }
+
+    /**
+     * EFFECTS: Encode into ordered DER.
+     */
+    @Override
+    public Byte[] encodeValueDER() {
+        return Stream.of(Arrays.asList(notBefore.encodeDER()),
+                Arrays.asList(notAfter.encodeDER()))
+                .flatMap(Collection::stream)
+                .toArray(Byte[]::new);
+    }
+
+    public ASN1Time getNotBefore() {
+        return notBefore;
+    }
+
+    public ASN1Time getNotAfter() {
+        return notAfter;
+    }
+}