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How to run java class implementation of elliptic curve encryption?
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.SecureRandom;
import java.security.Signature;
import java.security.SignatureException;
import java.security.spec.ECGenParameterSpec;
import javax.crypto.Cipher;
import org.bouncycastle.jce.spec.IEKeySpec;
import org.bouncycastle.jce.spec.IESParameterSpec;
public class ECIESexample {
private SecureRandom random;
private int keySize;
private KeyPair akey;
private KeyPair bkey;
public ECIESexample () throws Exception{
this.random = new SecureRandom();
}
public void establishKeys(String keysize) throws Exception {
ECGenParameterSpec ecGenSpec = new ECGenParameterSpec(keysize);
KeyPairGenerator keyGen = KeyPairGenerator.getInstance("EC");
keyGen.initialize(ecGenSpec, random);
this.akey = keyGen.generateKeyPair();
this.bkey = keyGen.generateKeyPair();
this.keySize = Integer.valueOf( (ecGenSpec.getName().substring(4, 7)) ).intValue();
}
public byte[] encrypt(byte[] plainText) throws Exception {
// get ECIES cipher objects
Cipher acipher = Cipher.getInstance("ECIES");
// generate derivation and encoding vectors
byte[] d = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
byte[] e = new byte[] { 8, 7, 6, 5, 4, 3, 2, 1 };
IESParameterSpec param = new IESParameterSpec(d, e, 256);
// encrypt the plaintext using the public key
acipher.init(Cipher.ENCRYPT_MODE, new IEKeySpec(akey.getPrivate(), bkey.getPublic()), param);
return acipher.doFinal(plainText);
}
public byte[] decrypt(byte[] cipherText) throws Exception {
// get ECIES cipher objects
Cipher bcipher = Cipher.getInstance("ECIES");
// generate derivation and encoding vectors
byte[] d = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
byte[] e = new byte[] { 8, 7, 6, 5, 4, 3, 2, 1 };
IESParameterSpec param = new IESParameterSpec(d, e, 256);
// decrypt the text using the private key
bcipher.init(Cipher.DECRYPT_MODE, new IEKeySpec(bkey.getPrivate(), akey.getPublic()), param);
return bcipher.doFinal(cipherText);
}
public byte[] sign(byte[] plainText) throws Exception {
Signature sig = Signature.getInstance("SHA1WithECDSA");
sig.initSign(akey.getPrivate());
sig.update(plainText);
return sig.sign();
}
public boolean verify(byte[] plainText, byte[] signature) throws Exception {
Signature sig = Signature.getInstance("SHA1WithECDSA");
sig.initVerify(akey.getPublic());
sig.update(plainText);
try {
if (sig.verify(signature)) {
return true;
} else return false;
} catch (SignatureException se) {
System.out.println( "Signature failed" );
}
return false;
}
public int getKeySize() {
return keySize;
}
}
public class encryption {
public static void main(String[] args) throws Exception{
ECIESexample en = new ECIESexample();
byte[] messageForEncrypt = "hello world -- a nice day today".getBytes();
en.encrypt(messageForEncrypt);
}
}
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