ECCEGKeyGenerator.java
bc9b923eb956develop

ECCEGKeyGenerator.java
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			package crypto.elgamal;

			import java.math.BigInteger;
			import java.security.SecureRandom;

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

			public class ECCEGKeyGenerator {

			private SecureRandom randGen;

			private BigInteger order;

			private X9ECParameters ecParams;

			public ECCEGKeyGenerator(String curveName) {
			this.randGen = new SecureRandom();
			this.ecParams = NISTNamedCurves.getByName(curveName);
			this.order = ecParams.getN();
			}

			/**
			*
			* @param order
			* order of the group
			* @return
			*/
			public KeyPair generateKey() {

			// generate the secret and random coefficient
			BigInteger secret = new BigInteger(order.bitLength() - 1, randGen);
			BigInteger a1 = new BigInteger(order.bitLength() - 1, randGen);

			BigInteger[] coefficients = new BigInteger[2];
			coefficients[0] = secret;
			coefficients[1] = a1;

			// generate both secret shares
			PartialSecret secretMU = new PartialSecret(PartialSecret.PART_MU, coefficients, order);
			PartialSecret secretSPU = new PartialSecret(PartialSecret.PART_SPU, coefficients, order);

			// generate public key
			ECPoint pubKey = ecParams.getG().multiply(secret);

			return new KeyPair(secretMU, secretSPU, pubKey);
			}
			}