1 files changed, 181 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/main/java/org/spongycastle/pqc/crypto/mceliece/McElieceParameters.java b/libraries/spongycastle/core/src/main/java/org/spongycastle/pqc/crypto/mceliece/McElieceParameters.java
new file mode 100644
index 000000000..d49f92793
--- /dev/null
+++ b/libraries/spongycastle/core/src/main/java/org/spongycastle/pqc/crypto/mceliece/McElieceParameters.java
@@ -0,0 +1,181 @@
+package org.spongycastle.pqc.crypto.mceliece;
+
+import org.spongycastle.crypto.CipherParameters;
+import org.spongycastle.pqc.math.linearalgebra.PolynomialRingGF2;
+
+public class McElieceParameters
+    implements CipherParameters
+{
+
+    /**
+     * The default extension degree
+     */
+    public static final int DEFAULT_M = 11;
+
+    /**
+     * The default error correcting capability.
+     */
+    public static final int DEFAULT_T = 50;
+
+    /**
+     * extension degree of the finite field GF(2^m)
+     */
+    private int m;
+
+    /**
+     * error correction capability of the code
+     */
+    private int t;
+
+    /**
+     * length of the code
+     */
+    private int n;
+
+    /**
+     * the field polynomial
+     */
+    private int fieldPoly;
+
+    /**
+     * Constructor. Set the default parameters: extension degree.
+     */
+    public McElieceParameters()
+    {
+        this(DEFAULT_M, DEFAULT_T);
+    }
+
+    /**
+     * Constructor.
+     *
+     * @param keysize the length of a Goppa code
+     * @throws IllegalArgumentException if <tt>keysize &lt; 1</tt>.
+     */
+    public McElieceParameters(int keysize)
+        throws IllegalArgumentException
+    {
+        if (keysize < 1)
+        {
+            throw new IllegalArgumentException("key size must be positive");
+        }
+        m = 0;
+        n = 1;
+        while (n < keysize)
+        {
+            n <<= 1;
+            m++;
+        }
+        t = n >>> 1;
+        t /= m;
+        fieldPoly = PolynomialRingGF2.getIrreduciblePolynomial(m);
+    }
+
+    /**
+     * Constructor.
+     *
+     * @param m degree of the finite field GF(2^m)
+     * @param t error correction capability of the code
+     * @throws IllegalArgumentException if <tt>m &lt; 1</tt> or <tt>m &gt; 32</tt> or
+     * <tt>t &lt; 0</tt> or <tt>t &gt; n</tt>.
+     */
+    public McElieceParameters(int m, int t)
+        throws IllegalArgumentException
+    {
+        if (m < 1)
+        {
+            throw new IllegalArgumentException("m must be positive");
+        }
+        if (m > 32)
+        {
+            throw new IllegalArgumentException("m is too large");
+        }
+        this.m = m;
+        n = 1 << m;
+        if (t < 0)
+        {
+            throw new IllegalArgumentException("t must be positive");
+        }
+        if (t > n)
+        {
+            throw new IllegalArgumentException("t must be less than n = 2^m");
+        }
+        this.t = t;
+        fieldPoly = PolynomialRingGF2.getIrreduciblePolynomial(m);
+    }
+
+    /**
+     * Constructor.
+     *
+     * @param m    degree of the finite field GF(2^m)
+     * @param t    error correction capability of the code
+     * @param poly the field polynomial
+     * @throws IllegalArgumentException if <tt>m &lt; 1</tt> or <tt>m &gt; 32</tt> or
+     * <tt>t &lt; 0</tt> or <tt>t &gt; n</tt> or
+     * <tt>poly</tt> is not an irreducible field polynomial.
+     */
+    public McElieceParameters(int m, int t, int poly)
+        throws IllegalArgumentException
+    {
+        this.m = m;
+        if (m < 1)
+        {
+            throw new IllegalArgumentException("m must be positive");
+        }
+        if (m > 32)
+        {
+            throw new IllegalArgumentException(" m is too large");
+        }
+        this.n = 1 << m;
+        this.t = t;
+        if (t < 0)
+        {
+            throw new IllegalArgumentException("t must be positive");
+        }
+        if (t > n)
+        {
+            throw new IllegalArgumentException("t must be less than n = 2^m");
+        }
+        if ((PolynomialRingGF2.degree(poly) == m)
+            && (PolynomialRingGF2.isIrreducible(poly)))
+        {
+            this.fieldPoly = poly;
+        }
+        else
+        {
+            throw new IllegalArgumentException(
+                "polynomial is not a field polynomial for GF(2^m)");
+        }
+    }
+
+    /**
+     * @return the extension degree of the finite field GF(2^m)
+     */
+    public int getM()
+    {
+        return m;
+    }
+
+    /**
+     * @return the length of the code
+     */
+    public int getN()
+    {
+        return n;
+    }
+
+    /**
+     * @return the error correction capability of the code
+     */
+    public int getT()
+    {
+        return t;
+    }
+
+    /**
+     * @return the field polynomial
+     */
+    public int getFieldPoly()
+    {
+        return fieldPoly;
+    }
+}