ECDSA算法教程以对字符串进行签名

这是基于您的示例的小示例。

注意： 这是此答案的原始代码，请参阅下一个代码片段以获取更新的版本。

import java.math.BigInteger;import java.security.KeyPair;import java.security.KeyPairGenerator;import java.security.PrivateKey;import java.security.PublicKey;import java.security.SecureRandom;import java.security.Signature;public class ECDSAExample {    public static void main(String[] args) throws Exception {                        KeyPairGenerator keyGen = KeyPairGenerator.getInstance("EC");        SecureRandom random = SecureRandom.getInstance("SHA1PRNG");        keyGen.initialize(256, random);        KeyPair pair = keyGen.generateKeyPair();        PrivateKey priv = pair.getPrivate();        PublicKey pub = pair.getPublic();                Signature dsa = Signature.getInstance("SHA1withECDSA");        dsa.initSign(priv);        String str = "This is string to sign";        byte[] strByte = str.getBytes("UTF-8");        dsa.update(strByte);                byte[] realSig = dsa.sign();        System.out.println("Signature: " + new BigInteger(1, realSig).toString(16));    }}

更新：这是删除过时算法的稍微改进的示例。它还使用RFC
8422中
指定的SECG标记“ secp256r1”明确请求NIST
P-256曲线。

import javax.xml.bind.DatatypeConverter;import java.security.*;import java.security.spec.ECGenParameterSpec;public class ECDSAExample {        public static void main(String[] args) throws Exception {                        KeyPairGenerator keyGen = KeyPairGenerator.getInstance("EC");        keyGen.initialize(new ECGenParameterSpec("secp256r1"), new SecureRandom());        KeyPair pair = keyGen.generateKeyPair();        PrivateKey priv = pair.getPrivate();        PublicKey pub = pair.getPublic();                Signature ecdsa = Signature.getInstance("SHA256withECDSA");        ecdsa.initSign(priv);        String str = "This is string to sign";        byte[] strByte = str.getBytes("UTF-8");        ecdsa.update(strByte);                byte[] realSig = ecdsa.sign();        System.out.println("Signature: " + new BigInteger(1, realSig).toString(16));    }}