将公钥转换为字符串，然后再将其转换回公钥Java

Question

将公钥转换为字符串，然后再将其转换回公钥Java

10

我有一段代码，想要进行一些转换。首先我生成一个公钥并打印出来，然后将其转换为字节，再转换为字符串。接下来，我又将其转换回字节，但是当我将其转换回字节时，字节的值会发生变化，因此生成的公钥与上面的不同，如下面的输出所示。

//generating public key     
PublicKey public_key = CryptographyHelper.ellipticCurveCrypto().getPublic();
System.out.println("PUBLIC KEY::" + public_key);

//converting public key to byte            
byte[] byte_pubkey = public_key.getEncoded();
System.out.println("\nBYTE KEY::: " + byte_pubkey);

//converting byte to String 
String str_key = Arrays.toString(byte_pubkey);
System.out.println("\nSTRING KEY::" + str_key);

//converting string to Bytes
byte_pubkey = str_key.getBytes();
System.out.println("BYTE KEY::" + byte_pubkey);

//converting it back to public key
KeyFactory factory = KeyFactory.getInstance("ECDSA", "BC");
public_key = (ECPublicKey) factory.generatePublic(new X509EncodedKeySpec(byte_pubkey));
System.out.println("FINAL OUTPUT" + public_key);

输出

    PUBLIC KEY::EC Public Key [4d:53:40:86:3f:a8:91:49:b6:27:b5:58:14:b8:8b:f1:ff:8a:78:70]
            X: c8e1028cad7b105814d4a2e0e292f5f7904aad7b6cbc46a5
            Y: 312272321a1ba4ff14caa73b42acb35eb025d9f6fc2ca6b3


BYTE KEY::: [B@1a1d6a08

STRING KEY::[48, 70, 48, 16, 6, 7, 42, -122, 72, -50, 61, 2, 1, 6, 5, 43, -127, 4, 0, 31, 3, 50, 0, 4, -56, -31, 2, -116, -83, 123, 16, 88, 20, -44, -94, -32, -30, -110, -11, -9, -112, 74, -83, 123, 108, -68, 70, -91, 49, 34, 114, 50, 26, 27, -92, -1, 20, -54, -89, 59, 66, -84, -77, 94, -80, 37, -39, -10, -4, 44, -90, -77]
BYTE KEY[B@37d31475
Exception in thread "main" java.security.spec.InvalidKeySpecException: encoded key spec not recognized: failed to construct sequence from byte[]: Extra data detected in stream
    at org.bouncycastle.jcajce.provider.asymmetric.util.BaseKeyFactorySpi.engineGeneratePublic(Unknown Source)
    at org.bouncycastle.jcajce.provider.asymmetric.ec.KeyFactorySpi.engineGeneratePublic(Unknown Source)
    at java.security.KeyFactory.generatePublic(KeyFactory.java:328)
    at blahblah.Driver.main(Driver.java:44)
C:\Users\blahblah\AppData\Local\NetBeans\Cache\8.1\executor-snippets\run.xml:53: Java returned: 1
BUILD FAILED (total time: 1 second)

我遇到了一个错误，因为当我第二次将它转换回字节并再次转换回公钥时，它变得无效，从而出现错误。 额外信息 但如果我只是这样做，它就可以正常工作，但我的目标是先以某种方式将公钥转换为字符串，然后将该字符串转换为公钥类型。我唯一能做到的就是将公钥（字符串类型）转换为字节类型，然后再将其转换回公钥。我不能直接将字符串转换为公钥，因为这样不起作用。

- c5564200

1

在创建和解析字节时，您应该查看使用的字符集。 - NielsNet

你能说一下你正在使用哪些库吗？ - Rathan Naik

2个回答

0

这是一个完整的示例，演示如何使用Bouncy Castle通过JCE生成ECDSA的公钥和私钥。

import org.bouncycastle.jce.provider.BouncyCastleProvider;

import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Security;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

import static org.bouncycastle.jce.ECNamedCurveTable.getParameterSpec;


public class PublicPrivateKeyExample {

    static {
        Security.addProvider(new BouncyCastleProvider());
    }

    private static final SecureRandom DEFAULT_SECURE_RANDOM;

    static {
        DEFAULT_SECURE_RANDOM = new SecureRandom();
        DEFAULT_SECURE_RANDOM.nextBytes(new byte[64]);
    }

    public static void main(String[] args) throws Exception {

        // -----
        // Create a random key-pair using ECDSA provided by bcprov-jdk15on from Bouncy Castle and encode as base64
        // strings
        // -----

        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("ECDSA", "BC");
        keyPairGenerator.initialize(getParameterSpec("secp521r1"), DEFAULT_SECURE_RANDOM);

        KeyPair keyPair = keyPairGenerator.generateKeyPair();
        PublicKey publicKey = keyPair.getPublic();
        PrivateKey privateKey = keyPair.getPrivate();

        Base64.Encoder encoder = Base64.getEncoder();
        String publicKeyStr = encoder.encodeToString(publicKey.getEncoded());
        String privateKeyStr = encoder.encodeToString(privateKey.getEncoded());

        // -----
        // Decode the base64 public and private keys back to a JCE's PublicKey and PrivateKey
        // -----

        KeyFactory keyFactory = KeyFactory.getInstance("ECDSA", "BC");
        Base64.Decoder decoder = Base64.getDecoder();

        PublicKey decodedPublicKey = keyFactory.generatePublic(new X509EncodedKeySpec(decoder.decode(publicKeyStr)));
        PrivateKey decodedPrivateKey =
                keyFactory.generatePrivate(new PKCS8EncodedKeySpec(decoder.decode(privateKeyStr)));

        assert publicKey.getEncoded() == decodedPublicKey.getEncoded();
        assert privateKey.getEncoded() == decodedPrivateKey.getEncoded();
    }
}

这是使用Java 8进行测试的，具体如下：

<dependency>
    <groupId>org.bouncycastle</groupId>
    <artifactId>bcprov-jdk15on</artifactId>
    <version>1.60</version>
</dependency>

- Michael Yakobi

感谢您的评论，对于Bouncycastle的实现非常有帮助。 - Joey Abano

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Rathan Naik · Accepted Answer

当转换为字符串类型时，您需要使用 Base64 编码系统。
tostring（）方法使用JVM默认编码，该编码不支持您的字符。

PublicKey public_key = CryptographyHelper.ellipticCurveCrypto().getPublic();     
System.out.println("PUBLIC KEY::" + public_key);

//converting public key to byte            
byte[] byte_pubkey = public_key.getEncoded();
System.out.println("\nBYTE KEY::: " + byte_pubkey);

//converting byte to String 
String str_key = Base64.getEncoder().encodeToString(byte_pubkey);
// String str_key = new String(byte_pubkey,Charset.);
System.out.println("\nSTRING KEY::" + str_key);

//converting string to Bytes
byte_pubkey  = Base64.getDecoder().decode(str_key);
System.out.println("BYTE KEY::" + byte_pubkey);


//converting it back to public key
KeyFactory factory = KeyFactory.getInstance("ECDSA", "BC");
public_key = (ECPublicKey) factory.generatePublic(new X509EncodedKeySpec(byte_pubkey));
System.out.println("FINAL OUTPUT" + public_key);