FieldSizeTest.java
40f60fbfc3aemaster

FieldSizeTest.java
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			package test;

			import java.math.BigInteger;

			import org.bouncycastle.asn1.nist.NISTNamedCurves;
			import org.bouncycastle.asn1.x9.X9ECParameters;
			import org.bouncycastle.math.ec.ECPoint;

			public class FieldSizeTest {

			public static void main(String[] args) {
			X9ECParameters curve = NISTNamedCurves.getByName("P-384");
			ECPoint g = curve.getG();
			BigInteger fieldSize = curve.getN();

			// Test 1: numbers correctly wrapped
			ECPoint pOutOfField = g.multiply(fieldSize.add(BigInteger.valueOf(1L)));
			ECPoint pWithinField = g;

			if (pOutOfField.equals(pWithinField)) {
			System.out.println("Equal");
			}
			else {
			System.out.println("Not equal");
			}

			// Test 2: numbers adding and substracting correctly
			ECPoint p1Small = g.multiply(BigInteger.valueOf(8));
			ECPoint p1Large = g.multiply(fieldSize.multiply(BigInteger.valueOf(100L)));
			ECPoint sum = p1Small.add(p1Large);
			ECPoint p1SmallPrime = sum.subtract(p1Large);

			if (p1Small.equals(p1SmallPrime)) {
			System.out.println("Points are equal");
			}
			else {
			System.out.println("Points are the same");
			}
			}
			}