1 files changed, 68 insertions, 0 deletions
diff --git a/core/src/main/java/org/spongycastle/asn1/x9/KeySpecificInfo.java b/core/src/main/java/org/spongycastle/asn1/x9/KeySpecificInfo.java
new file mode 100644
index 00000000..3a7f9517
--- /dev/null
+++ b/core/src/main/java/org/spongycastle/asn1/x9/KeySpecificInfo.java
@@ -0,0 +1,68 @@
+package org.spongycastle.asn1.x9;
+
+import java.util.Enumeration;
+
+import org.spongycastle.asn1.ASN1EncodableVector;
+import org.spongycastle.asn1.ASN1Object;
+import org.spongycastle.asn1.ASN1ObjectIdentifier;
+import org.spongycastle.asn1.ASN1OctetString;
+import org.spongycastle.asn1.ASN1Primitive;
+import org.spongycastle.asn1.ASN1Sequence;
+import org.spongycastle.asn1.DERSequence;
+
+/**
+ * ASN.1 def for Diffie-Hellman key exchange KeySpecificInfo structure. See
+ * RFC 2631, or X9.42, for further details.
+ */
+public class KeySpecificInfo
+    extends ASN1Object
+{
+    private ASN1ObjectIdentifier algorithm;
+    private ASN1OctetString      counter;
+
+    public KeySpecificInfo(
+        ASN1ObjectIdentifier algorithm,
+        ASN1OctetString      counter)
+    {
+        this.algorithm = algorithm;
+        this.counter = counter;
+    }
+
+    public KeySpecificInfo(
+        ASN1Sequence  seq)
+    {
+        Enumeration e = seq.getObjects();
+
+        algorithm = (ASN1ObjectIdentifier)e.nextElement();
+        counter = (ASN1OctetString)e.nextElement();
+    }
+
+    public ASN1ObjectIdentifier getAlgorithm()
+    {
+        return algorithm;
+    }
+
+    public ASN1OctetString getCounter()
+    {
+        return counter;
+    }
+
+    /**
+     * Produce an object suitable for an ASN1OutputStream.
+     * <pre>
+     *  KeySpecificInfo ::= SEQUENCE {
+     *      algorithm OBJECT IDENTIFIER,
+     *      counter OCTET STRING SIZE (4..4)
+     *  }
+     * </pre>
+     */
+    public ASN1Primitive toASN1Primitive()
+    {
+        ASN1EncodableVector  v = new ASN1EncodableVector();
+
+        v.add(algorithm);
+        v.add(counter);
+
+        return new DERSequence(v);
+    }
+}