BouncyCastle 密钥转换 - Java

转自: https://blog.csdn.net/a351945755/article/details/63707040

 

1. PKCS#8 转 PKCS#1

You will need BouncyCastle:

import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.pkcs.PrivateKeyInfo;
import org.bouncycastle.asn1.x509.SubjectPublicKeyInfo;
import org.bouncycastle.util.io.pem.PemObject;
import org.bouncycastle.util.io.pem.PemWriter;

The code snippets below have been checked and found working with Bouncy Castle 1.52.

Private key

Convert private key from PKCS8 to PKCS1:

PrivateKey priv = pair.getPrivate();
byte[] privBytes = priv.getEncoded();

PrivateKeyInfo pkInfo = PrivateKeyInfo.getInstance(privBytes);
ASN1Encodable encodable = pkInfo.parsePrivateKey();
ASN1Primitive primitive = encodable.toASN1Primitive();
byte[] privateKeyPKCS1 = primitive.getEncoded();

====>

//pkcs8Bytes contains PKCS#8 DER-encoded key as a byte[]
PrivateKeyInfo pki = PrivateKeyInfo.getInstance(encodeByte);
RSAPrivateKeyStructure pkcs1Key = RSAPrivateKeyStructure.getInstance(pki.getPrivateKey());
byte[] pkcs1Bytes = pkcs1Key.getEncoded();//etc.

Convert private key in PKCS1 to PEM:

PemObject pemObject = new PemObject("RSA PRIVATE KEY", privateKeyPKCS1);
StringWriter stringWriter = new StringWriter();
PemWriter pemWriter = new PemWriter(stringWriter);
pemWriter.writeObject(pemObject);
pemWriter.close();
String pemString = stringWriter.toString();

Check with command line OpenSSL that the key format is as expected:

openssl rsa -in rsa_private_key.pem -noout -text

 

2. PKCS#1 转 PKCS#8

//format PKCS#1 to PKCS#8
public static String formatPkcs1ToPkcs8(String rawKey) throws Exception {
    String result = null;
    //extract valid key content
    String validKey = RsaPemUtil.extractFromPem(rawKey);
    if(!Strings.isNullOrEmpty(validKey)) {
        //将BASE64编码的私钥字符串进行解码
        byte[] encodeByte = Base64.decodeBase64(validKey);
        AlgorithmIdentifier algorithmIdentifier = new AlgorithmIdentifier(PKCSObjectIdentifiers.pkcs8ShroudedKeyBag);    //PKCSObjectIdentifiers.pkcs8ShroudedKeyBag        
        ASN1Object asn1Object = ASN1Object.fromByteArray(encodeByte);
        PrivateKeyInfo privKeyInfo = new PrivateKeyInfo(algorithmIdentifier, asn1Object);            
        byte[] pkcs8Bytes = privKeyInfo.getEncoded();
        
        String type = "PRIVATE KEY";
        result = format2PemString(type, pkcs8Bytes);
    }
    return result;
}

Notice:

生成出来的代码与openssl转换的还是有点不一样，主要是第一行。可能是有些属性字段不同，但经测试上述代码转换产生的key也可以解码。

 

3. 完整代码

import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.Security;
import java.security.interfaces.RSAPrivateCrtKey;
import java.security.spec.EncodedKeySpec;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.RSAPrivateKeySpec;
import java.util.List;

import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1Object;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers;
import org.bouncycastle.asn1.pkcs.PrivateKeyInfo;
import org.bouncycastle.asn1.pkcs.RSAPrivateKeyStructure;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.crypto.AsymmetricCipherKeyPair;
import org.bouncycastle.util.io.pem.PemObject;
import org.bouncycastle.util.io.pem.PemReader;
import org.bouncycastle.util.io.pem.PemWriter;
import org.bouncycastle.openssl.MiscPEMGenerator;
import org.bouncycastle.openssl.PKCS8Generator;

import com.ctrip.lzyan.test.cipher.cscm.RsaPemUtil;
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.base.Strings;
import com.google.common.collect.Lists;
import org.apache.commons.codec.binary.Base64;

/**
 * Transform PKCS format
 *     PKCS#1    -> PKCS#8
 *     PKCS#8    -> PKCS#1
 * 
 */
public class RsaPkcsTransformer {
    private static final String COMMENT_BEGIN_FLAG = "-----";
    private static final String RETURN_FLAG_R = "\r";
    private static final String RETURN_FLAG_N = "\n";
    
    
        
    //format PKCS#8 to PKCS#1
    public static String formatPkcs8ToPkcs1(String rawKey) throws Exception {
        String result = null;
        //extract valid key content
        String validKey = RsaPemUtil.extractFromPem(rawKey);
        if(!Strings.isNullOrEmpty(validKey)) {
            //将BASE64编码的私钥字符串进行解码
            byte[] encodeByte = Base64.decodeBase64(validKey);
                                    
            //==========
            //pkcs8Bytes contains PKCS#8 DER-encoded key as a byte[]
            PrivateKeyInfo pki = PrivateKeyInfo.getInstance(encodeByte);
            RSAPrivateKeyStructure pkcs1Key = RSAPrivateKeyStructure.getInstance(pki.getPrivateKey());
            byte[] pkcs1Bytes = pkcs1Key.getEncoded();//etc.
            //==========
            
            String type = "RSA PRIVATE KEY";
            result = format2PemString(type, pkcs1Bytes);            
        }
        return result;
    }
    
    //format PKCS#1 to PKCS#8
    public static String formatPkcs1ToPkcs8(String rawKey) throws Exception {
        String result = null;
        //extract valid key content
        String validKey = RsaPemUtil.extractFromPem(rawKey);
        if(!Strings.isNullOrEmpty(validKey)) {
            //将BASE64编码的私钥字符串进行解码
            byte[] encodeByte = Base64.decodeBase64(validKey);
            
            AlgorithmIdentifier algorithmIdentifier = new AlgorithmIdentifier(PKCSObjectIdentifiers.pkcs8ShroudedKeyBag);    //PKCSObjectIdentifiers.pkcs8ShroudedKeyBag        
            ASN1Object asn1Object = ASN1Object.fromByteArray(encodeByte);
            PrivateKeyInfo privKeyInfo = new PrivateKeyInfo(algorithmIdentifier, asn1Object);            
            byte[] pkcs8Bytes = privKeyInfo.getEncoded();
            
            String type = "PRIVATE KEY";
            result = format2PemString(type, pkcs8Bytes);
            
        }
        return result;
    }
    
    // Write to pem file
    private static String format2PemString(String type, byte[] privateKeyPKCS1) throws Exception {
        PemObject pemObject = new PemObject(type, privateKeyPKCS1);
        StringWriter stringWriter = new StringWriter();
        PemWriter pemWriter = new PemWriter(stringWriter);
        pemWriter.writeObject(pemObject);
        pemWriter.close();
        String pemString = stringWriter.toString();
        return pemString;
    }
    
    //=== Testing ===
    public static void main(String[] args) throws Exception {
        String rawKey_pkcs1 = "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";
        String rawKey_pkcs8 = "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";
        
        //rawKey_pkcs1 = "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";

        String formatKey = formatPkcs1ToPkcs8(rawKey_pkcs1);
        //String formatKey = formatPkcs8ToPkcs1(rawKey_pkcs8);
        System.out.println(formatKey);    //expect: abcdef
    }
    
}

RsaPkcsTransformer