1 files changed, 155 insertions, 0 deletions
diff --git a/core/src/main/java/org/spongycastle/pqc/crypto/gmss/GMSSParameters.java b/core/src/main/java/org/spongycastle/pqc/crypto/gmss/GMSSParameters.java
new file mode 100644
index 00000000..c78d50e3
--- /dev/null
+++ b/core/src/main/java/org/spongycastle/pqc/crypto/gmss/GMSSParameters.java
@@ -0,0 +1,155 @@
+package org.spongycastle.pqc.crypto.gmss;
+
+import org.spongycastle.util.Arrays;
+
+/**
+ * This class provides a specification for the GMSS parameters that are used by
+ * the GMSSKeyPairGenerator and GMSSSignature classes.
+ *
+ * @see org.spongycastle.pqc.crypto.gmss.GMSSKeyPairGenerator
+ */
+public class GMSSParameters
+{
+    /**
+     * The number of authentication tree layers.
+     */
+    private int numOfLayers;
+
+    /**
+     * The height of the authentication trees of each layer.
+     */
+    private int[] heightOfTrees;
+
+    /**
+     * The Winternitz Parameter 'w' of each layer.
+     */
+    private int[] winternitzParameter;
+
+    /**
+     * The parameter K needed for the authentication path computation
+     */
+    private int[] K;
+
+    /**
+     * The constructor for the parameters of the GMSSKeyPairGenerator.
+     *
+     * @param layers              the number of authentication tree layers
+     * @param heightOfTrees       the height of the authentication trees
+     * @param winternitzParameter the Winternitz Parameter 'w' of each layer
+     * @param K                   parameter for authpath computation
+     */
+    public GMSSParameters(int layers, int[] heightOfTrees, int[] winternitzParameter, int[] K)
+        throws IllegalArgumentException
+    {
+        init(layers, heightOfTrees, winternitzParameter, K);
+    }
+
+    private void init(int layers, int[] heightOfTrees,
+                      int[] winternitzParameter, int[] K)
+        throws IllegalArgumentException
+    {
+        boolean valid = true;
+        String errMsg = "";
+        this.numOfLayers = layers;
+        if ((numOfLayers != winternitzParameter.length)
+            || (numOfLayers != heightOfTrees.length)
+            || (numOfLayers != K.length))
+        {
+            valid = false;
+            errMsg = "Unexpected parameterset format";
+        }
+        for (int i = 0; i < numOfLayers; i++)
+        {
+            if ((K[i] < 2) || ((heightOfTrees[i] - K[i]) % 2 != 0))
+            {
+                valid = false;
+                errMsg = "Wrong parameter K (K >= 2 and H-K even required)!";
+            }
+
+            if ((heightOfTrees[i] < 4) || (winternitzParameter[i] < 2))
+            {
+                valid = false;
+                errMsg = "Wrong parameter H or w (H > 3 and w > 1 required)!";
+            }
+        }
+
+        if (valid)
+        {
+            this.heightOfTrees = Arrays.clone(heightOfTrees);
+            this.winternitzParameter = Arrays.clone(winternitzParameter);
+            this.K = Arrays.clone(K);
+        }
+        else
+        {
+            throw new IllegalArgumentException(errMsg);
+        }
+    }
+
+    public GMSSParameters(int keySize)
+        throws IllegalArgumentException
+    {
+        if (keySize <= 10)
+        { // create 2^10 keys
+            int[] defh = {10};
+            int[] defw = {3};
+            int[] defk = {2};
+            this.init(defh.length, defh, defw, defk);
+        }
+        else if (keySize <= 20)
+        { // create 2^20 keys
+            int[] defh = {10, 10};
+            int[] defw = {5, 4};
+            int[] defk = {2, 2};
+            this.init(defh.length, defh, defw, defk);
+        }
+        else
+        { // create 2^40 keys, keygen lasts around 80 seconds
+            int[] defh = {10, 10, 10, 10};
+            int[] defw = {9, 9, 9, 3};
+            int[] defk = {2, 2, 2, 2};
+            this.init(defh.length, defh, defw, defk);
+        }
+    }
+
+    /**
+     * Returns the number of levels of the authentication trees.
+     *
+     * @return The number of levels of the authentication trees.
+     */
+    public int getNumOfLayers()
+    {
+        return numOfLayers;
+    }
+
+    /**
+     * Returns the array of height (for each layer) of the authentication trees
+     *
+     * @return The array of height (for each layer) of the authentication trees
+     */
+    public int[] getHeightOfTrees()
+    {
+        return Arrays.clone(heightOfTrees);
+    }
+
+    /**
+     * Returns the array of WinternitzParameter (for each layer) of the
+     * authentication trees
+     *
+     * @return The array of WinternitzParameter (for each layer) of the
+     *         authentication trees
+     */
+    public int[] getWinternitzParameter()
+    {
+        return Arrays.clone(winternitzParameter);
+    }
+
+    /**
+     * Returns the parameter K needed for authentication path computation
+     *
+     * @return The parameter K needed for authentication path computation
+     */
+    public int[] getK()
+    {
+        return Arrays.clone(K);
+    }
+}