Generate Public Key From Private Key Ecdsa Encryption Java

Generate Rsa Public Private Key
Generate Rsa Public Key

Oct 04, 2019 ECDSA with secp256k1 in Java: generate ECC keys, sign, verify - ECDSA-secp256k1-example.java. Sep 11, 2012 This site uses cookies for analytics, personalized content and ads. By continuing to browse this site, you agree to this use.

ECDSA with secp256k1 in Java: generate ECC keys, sign, verify

ECDSA-secp256k1-example.java

importorg.bouncycastle.util.encoders.Hex;

importorg.web3j.crypto.*;

importjava.math.BigInteger;

publicclassECCExample {

publicstaticStringcompressPubKey(BigIntegerpubKey) {

String pubKeyYPrefix = pubKey.testBit(0) ?'03':'02';

String pubKeyHex = pubKey.toString(16);

String pubKeyX = pubKeyHex.substring(0, 64);

return pubKeyYPrefix + pubKeyX;

}

publicstaticvoidmain(String[] args) throwsException {

//BigInteger privKey = Keys.createEcKeyPair().getPrivateKey();

BigInteger privKey =newBigInteger('97ddae0f3a25b92268175400149d65d6887b9cefaf28ea2c078e05cdc15a3c0a', 16);

BigInteger pubKey =Sign.publicKeyFromPrivate(privKey);

ECKeyPair keyPair =newECKeyPair(privKey, pubKey);

System.out.println('Private key: '+ privKey.toString(16));

System.out.println('Public key: '+ pubKey.toString(16));

System.out.println('Public key (compressed): '+ compressPubKey(pubKey));

String msg ='Message for signing';

byte[] msgHash =Hash.sha3(msg.getBytes());

Sign.SignatureData signature =Sign.signMessage(msgHash, keyPair, false);

System.out.println('Msg: '+ msg);

System.out.println('Msg hash: '+Hex.toHexString(msgHash));

System.out.printf('Signature: [v = %d, r = %s, s = %s]n',

signature.getV() -27,

Hex.toHexString(signature.getR()),

Hex.toHexString(signature.getS()));

System.out.println();

BigInteger pubKeyRecovered =Sign.signedMessageToKey(msg.getBytes(), signature);

System.out.println('Recovered public key: '+ pubKeyRecovered.toString(16));

boolean validSig = pubKey.equals(pubKeyRecovered);

System.out.println('Signature valid? '+ validSig);

}

Generate Public Key From Private Key Ecdsa Encryption Java

pom.xml

<?xml version='1.0' encoding='UTF-8'?>

<projectxmlns='http://maven.apache.org/POM/4.0.0'

xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'

xsi:schemaLocation='http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd'>

<groupId>bc-examples</groupId>

<artifactId>bc-examples</artifactId>

<version>1.0-SNAPSHOT</version>

<artifactId>crypto</artifactId>

</dependency>

</dependencies>

</project>

commented Apr 5, 2018

The expected output is as follows:

Generate Rsa Public Private Key

commented Sep 16, 2018

java.security package contains ECDSA classes for generating the key pair, signing and verifying signatures.

commented Apr 5, 2018

Generate Rsa Public Private Key

commented Sep 16, 2018

Generate Rsa Public Key