Question

我正在尝试学习一些Go和区块链。从ECDSA签名开始。试图弄清楚如何测试我是否有一个正确工作的ECDSA签名的Go实现，我想我会尝试在Java中创建一个类似的版本并比较结果，看看我是否可以让它们匹配。

所以Java尝试：

public static void main(String[] args) throws Exception {
    //the keys below are previously generated with "generateKey();" and base64 encoded
    generateKey();
    String privStr = "MEECAQAwEwYHKoZIzj0CAQYIKoZIzj0DAQcEJzAlAgEBBCAQ7bMVIcWr9NpSD3hPkns5C0qET87UvyY5WI6UML2p0Q==";
    String pubStr = "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAES8VdACZT/9u1NmaiQk0KIjEXxiaxms74nu/ps6bP0OvYMIlTdIWWU2s35LEKsNJH9u5QM2ocX53BPjwbsENXJw==";
    PrivateKey privateKey = base64ToPrivateKey(privStr);
    PublicKey publicKey = base64ToPublicKey(pubStr);
    String str = "This is string to sign";
    byte[] signature = signMsg(str, privateKey);
    boolean ok = verifySignature(publicKey, str, signature);
    System.out.println("signature ok:" + ok);
    String privHex = getPrivateKeyAsHex(privateKey);
}

public static byte[] signMsg(String msg, PrivateKey priv) throws Exception {
    Signature ecdsa = Signature.getInstance("SHA1withECDSA");

    ecdsa.initSign(priv);

    byte[] strByte = msg.getBytes("UTF-8");
    ecdsa.update(strByte);

    byte[] realSig = ecdsa.sign();
    //the printed signature from here is what is used in the Go version (hex string)
    System.out.println("Signature: " + new BigInteger(1, realSig).toString(16));
    return realSig;
}

//https://stackoverflow.com/questions/30175149/error-when-verifying-ecdsa-signature-in-java-with-bouncycastle

private static boolean verifySignature(PublicKey pubKey, String msg, byte[] signature) throws Exception {
    byte[] message = msg.getBytes("UTF-8");
    Signature ecdsa = Signature.getInstance("SHA1withECDSA");
    ecdsa.initVerify(pubKey);
    ecdsa.update(message);
    return ecdsa.verify(signature);
}

public static String generateKey() throws Exception {
    KeyPairGenerator keyGen = KeyPairGenerator.getInstance("EC");
    SecureRandom random = SecureRandom.getInstance("SHA1PRNG");

    keyGen.initialize(256, random); //256 bit key size

    KeyPair pair = keyGen.generateKeyPair();
    PrivateKey priv = pair.getPrivate();
    ECPrivateKey ePriv = (ECPrivateKey) priv;
    PublicKey pub = pair.getPublic();

    //https://stackoverflow.com/questions/5355466/converting-secret-key-into-a-string-and-vice-versa
    String encodedPrivateKey = Base64.getEncoder().encodeToString(priv.getEncoded());
    byte[] pubEncoded = pub.getEncoded();
    String encodedPublicKey = Base64.getEncoder().encodeToString(pubEncoded);
    System.out.println(encodedPrivateKey);
    System.out.println(encodedPublicKey);
    return encodedPrivateKey;
}

public static PrivateKey base64ToPrivateKey(String encodedKey) throws Exception {
    byte[] decodedKey = Base64.getDecoder().decode(encodedKey);
    return bytesToPrivateKey(decodedKey);
}

public static PrivateKey bytesToPrivateKey(byte[] pkcs8key) throws GeneralSecurityException {
    PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(pkcs8key);
    KeyFactory factory = KeyFactory.getInstance("EC");
    PrivateKey privateKey = factory.generatePrivate(spec);
    return privateKey;
}

public static PublicKey base64ToPublicKey(String encodedKey) throws Exception {
    byte[] decodedKey = Base64.getDecoder().decode(encodedKey);
    return bytesToPublicKey(decodedKey);
}

public static PublicKey bytesToPublicKey(byte[] x509key) throws GeneralSecurityException {
    X509EncodedKeySpec spec = new X509EncodedKeySpec(x509key);
    KeyFactory factory = KeyFactory.getInstance("EC");
    PublicKey publicKey = factory.generatePublic(spec);
    return publicKey;
}

//https://stackoverflow.com/questions/40552688/generating-a-ecdsa-private-key-in-bouncy-castle-returns-a-public-key
private static String getPrivateKeyAsHex(PrivateKey privateKey) {
    ECPrivateKey ecPrivateKey = (ECPrivateKey) privateKey;
    byte[] privateKeyBytes = ecPrivateKey.getS().toByteArray();
    System.out.println("S:"+ecPrivateKey.getS());

    String hex = bytesToHex(privateKeyBytes);

    System.out.println("Private key bytes: " + Arrays.toString(privateKeyBytes));
    System.out.println("Private key hex: " + hex);

    return hex;
}

private final static char[] hexArray = "0123456789ABCDEF".toCharArray();

public static String bytesToHex(byte[] bytes) {
    char[] hexChars = new char[bytes.length * 2];
    for (int j = 0 ; j < bytes.length ; j++) {
        int v = bytes[j] & 0xFF;
        hexChars[j * 2] = hexArray[v >>> 4];
        hexChars[j * 2 + 1] = hexArray[v & 0x0F];
    }
    return new String(hexChars);
}

在Java中进行签名和验证工作正常。当然容易配置，因为它们都是相同的库，参数等等。

要在Go中验证相同的签名，我尝试了：

func TestSigning(t *testing.T) {
    privKey := hexToPrivateKey("10EDB31521C5ABF4DA520F784F927B390B4A844FCED4BF2639588E9430BDA9D1")
    pubKey := privKey.Public()
    sig := "3045022071f06054f450f808aa53294d34f76afd288a23749628cc58add828e8b8f2b742022100f82dcb51cc63b29f4f8b0b838c6546be228ba11a7c23dc102c6d9dcba11a8ff2"
    sigHex, _ := hex.DecodeString(sig)
    ePubKey := pubKey.(*ecdsa.PublicKey)
    ok := verifyMySig(ePubKey, "This is string to sign", sigHex)
    println(ok)
}

func verifyMySig(pub *ecdsa.PublicKey, msg string, sig []byte) bool {
    r := new(big.Int).SetBytes(sig[:len(sig)/2])
    s := new(big.Int).SetBytes(sig[len(sig)/2:])
    return ecdsa.Verify(pub, []byte(msg), r, s)
}

func hexToPrivateKey(hexStr string)  *ecdsa.PrivateKey {
    bytes, _ := hex.DecodeString(hexStr)

    k := new(big.Int)
    k.SetBytes(bytes)
    println("k:")
    fmt.Println(k.String())

    priv := new(ecdsa.PrivateKey)
    curve := elliptic.P256()
    priv.PublicKey.Curve = curve
    priv.D = k
    priv.PublicKey.X, priv.PublicKey.Y = curve.ScalarBaseMult(k.Bytes())

    return priv
}

最初，我尝试将Java中的私钥导出为base64编码字符串，并将其导入Go。但我无法弄清楚如何（如果（X509EncodedKeySpec））以Java存储格式加载Go加载密钥。所以相反，我尝试这种方式只复制私钥的大整数，并从中生成公钥。如果我这样做，那么尝试只复制公钥..

无论如何，Go代码无法验证签名。它总是错误的。另外，我无法从“SHA1withECDSA”部分找出将SHA功能放在Go中的位置。

我确信我在这里遗漏了一些基本概念。如何正确地做到这一点？

Answer 1

管理让这个工作。所以只为自己和任何有兴趣的人记录它。

正如评论中所指出的，Java的签名是ASN1格式。在这里找到了一个很好的格式描述：https://crypto.stackexchange.com/questions/1795/how-can-i-convert-a-der-ecdsa-signature-to-asn-1。

我还在https://github.com/gtank/cryptopasta（sign.go和sign_test.go）的Go中找到了一些关于如何使用ECDSA进行SHAxx的好例子。只需要在ECDSA代码之前运行相关的SHA函数。

找到用于从http://codrspace.com/supcik/golang-jwt-ecdsa/的Go中的参数构建公钥的示例代码。

我粘贴下面的相关代码，如果有人发现问题，请告诉我..

ECDSA签名Java vs Go

1 个答案: