1 files changed, 83 insertions, 0 deletions
diff --git a/src/main/model/csr/Attribute.java b/src/main/model/csr/Attribute.java
new file mode 100644
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+++ b/src/main/model/csr/Attribute.java
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+package model.csr;
+
+import model.asn1.ASN1Object;
+import model.asn1.ObjectIdentifier;
+import model.asn1.Tag;
+import model.asn1.exceptions.ParseException;
+import model.asn1.parsing.BytesReader;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.stream.Stream;
+
+/**
+ * Implements the following:
+ * <pre>
+ *   Attribute { ATTRIBUTE:IOSet } ::= SEQUENCE {
+ *       type   ATTRIBUTE.&id({IOSet}),
+ *       values SET SIZE(1..MAX) OF ATTRIBUTE.&Type({IOSet}{@type})
+ *   }
+ * </pre>
+ *
+ * Represents a key - values pair in the CSR attribute.
+ */
+public class Attribute extends ASN1Object {
+    /**
+     * The type of that attribute. For example, <pre>2.5.29.14</pre> is subjectKeyIdentifier.
+     * It determines the format of the value.
+     */
+    private final ObjectIdentifier type;
+
+    /**
+     * Value set.
+     */
+    private final Values values;
+
+    /**
+     * EFFECT: Init the object with tag, parentTag, type, and values. For tag and parentTag, see {@link ASN1Object}.
+     * REQUIRES: The values must match the type. Type tag should be UNIVERSAL OID, and values should be SET OF.
+     */
+    public Attribute(Tag tag, Tag parentTag,
+                      ObjectIdentifier type, Values values) {
+        super(tag, parentTag);
+        this.type = type;
+        this.values = values;
+    }
+
+    /**
+     * EFFECTS: Parse input DER. Value is not checked against the type.
+     *   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 Attribute(BytesReader encoded, boolean hasParentTag) throws ParseException {
+        super(encoded, hasParentTag);
+        this.type = new ObjectIdentifier(encoded, false);
+        this.type.getTag().enforce(ObjectIdentifier.TAG);
+
+        this.values = new Values(encoded, false);
+        this.values.getTag().enforce(TAG_SET);
+    }
+
+    /**
+     * EFFECTS: Encode the fields into DER, in the order.
+     */
+    @Override
+    public Byte[] encodeValueDER() {
+        return Stream.of(Arrays.asList(type.encodeDER()),
+                Arrays.asList(values.encodeDER()))
+                .flatMap(Collection::stream)
+                .toArray(Byte[]::new);
+    }
+
+    public ObjectIdentifier getType() {
+        return type;
+    }
+
+    public Values getValues() {
+        return values;
+    }
+}