1 files changed, 47 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/test/java/org/spongycastle/pqc/math/ntru/polynomial/test/BigDecimalPolynomialTest.java b/libraries/spongycastle/core/src/test/java/org/spongycastle/pqc/math/ntru/polynomial/test/BigDecimalPolynomialTest.java
new file mode 100644
index 000000000..fdeb68555
--- /dev/null
+++ b/libraries/spongycastle/core/src/test/java/org/spongycastle/pqc/math/ntru/polynomial/test/BigDecimalPolynomialTest.java
@@ -0,0 +1,47 @@
+package org.spongycastle.pqc.math.ntru.polynomial.test;
+
+import java.math.BigDecimal;
+import java.security.SecureRandom;
+
+import junit.framework.TestCase;
+import org.spongycastle.pqc.math.ntru.polynomial.BigDecimalPolynomial;
+import org.spongycastle.pqc.math.ntru.polynomial.BigIntPolynomial;
+import org.spongycastle.pqc.math.ntru.polynomial.DenseTernaryPolynomial;
+import org.spongycastle.pqc.math.ntru.polynomial.IntegerPolynomial;
+
+public class BigDecimalPolynomialTest
+    extends TestCase
+{
+    public void testMult()
+    {
+        BigDecimalPolynomial a = new BigDecimalPolynomial(new BigIntPolynomial(new IntegerPolynomial(new int[]{4, -1, 9, 2, 1, -5, 12, -7, 0, -9, 5})));
+        BigDecimalPolynomial b = new BigDecimalPolynomial(new BigIntPolynomial(new IntegerPolynomial(new int[]{-6, 0, 0, 13, 3, -2, -4, 10, 11, 2, -1})));
+        BigDecimalPolynomial c = a.mult(b);
+        BigDecimal[] expectedCoeffs = new BigDecimalPolynomial(new BigIntPolynomial(new IntegerPolynomial(new int[]{2, -189, 77, 124, -29, 0, -75, 124, -49, 267, 34}))).getCoeffs();
+
+        BigDecimal[] cCoeffs = c.getCoeffs();
+
+        assertEquals(expectedCoeffs.length, cCoeffs.length);
+        for (int i = 0; i != cCoeffs.length; i++)
+        {
+            assertEquals(expectedCoeffs[i], cCoeffs[i]);
+        }
+
+        // multiply a polynomial by its inverse modulo 2048 and check that the result is 1
+        SecureRandom random = new SecureRandom();
+        IntegerPolynomial d, dInv;
+        do
+        {
+            d = DenseTernaryPolynomial.generateRandom(1001, 333, 334, random);
+            dInv = d.invertFq(2048);
+        }
+        while (dInv == null);
+
+        d.mod(2048);
+        BigDecimalPolynomial e = new BigDecimalPolynomial(new BigIntPolynomial(d));
+        BigIntPolynomial f = new BigIntPolynomial(dInv);
+        IntegerPolynomial g = new IntegerPolynomial(e.mult(f).round());
+        g.modPositive(2048);
+        assertTrue(g.equalsOne());
+    }
+}
+\ No newline at end of file