Pem私钥pkcs1和pkcs8之间互转

pkcs8私钥转pkcs1私钥

方法1：使用OpenSSL工具转化

openssl rsa -in pkcs8.pem -out pkcs1.pem

命令执行完后，当前文件目录下将出现一个名为

pkcs1.pem

的文件，即为pkcs1格式。

方法2：通过代码实现

jar包版本

<dependency><groupId>org.bouncycastle</groupId><artifactId>bcpkix-jdk18on</artifactId><version>1.72</version></dependency>

代码如下

privatestaticfinalString CHARSET ="utf-8";/**
     * pkcs8私钥文件转化为pkcs1私钥文件
     * @param pkcs8Key
     * @param pkcs1KeyFilePath
     * @param pkcs1KeyFileName
     * @return
     * @throws Exception
     */publicstaticFileformatPkcs8ToPkcs1(File pkcs8Key,String pkcs1KeyFilePath,String pkcs1KeyFileName)throwsException{PemObject object =null;try(PemReader pemReader =newPemReader(newFileReader(pkcs8Key))){
            object =  pemReader.readPemObject();}/**将私钥从PKCS8转换为PKCS1**/PrivateKeyInfo pkInfo =PrivateKeyInfo.getInstance(object.getContent());ASN1Encodable encodable = pkInfo.parsePrivateKey();ASN1Primitive primitive = encodable.toASN1Primitive();byte[] privateKeyPKCS1 = primitive.getEncoded();/**将PKCS1中的私钥转换为PEM**/PemObject pemObject =newPemObject("RSA PRIVATE KEY", privateKeyPKCS1);try(StringWriter stringWriter =newStringWriter()){PemWriter pemWriter =newPemWriter(stringWriter);
            pemWriter.writeObject(pemObject);
            pemWriter.flush();String pemString = stringWriter.toString();File pem =newFile(pkcs1KeyFilePath, pkcs1KeyFileName);FileUtils.writeStringToFile(pem, pemString, CHARSET);return pem;}}

方法3：通过hutool实现

该实现方法通过hutool读取秘钥文件，既没有降低代码复杂度，也没有减少jar包依赖，并不推荐使用。

jar版本

<dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId><version>5.8.8</version></dependency><dependency><groupId>org.bouncycastle</groupId><artifactId>bcpkix-jdk18on</artifactId><version>1.72</version></dependency>

代码如下

privatestaticfinalString CHARSET ="utf-8";/**
     * pkcs8私钥转化为pkcs1私钥
     * @param pkcs8Key
     * @param pkcs1KeyFilePath
     * @param pkcs1KeyFileName
     * @return
     * @throws Exception
     */publicstaticFileformatPkcs8ToPkcs1ByHutool(File pkcs8Key,String pkcs1KeyFilePath,String pkcs1KeyFileName)throwsException{PrivateKey privKeyInfo =PemUtil.readPemPrivateKey(newFileInputStream(pkcs8Key));/**将私钥从PKCS8转换为PKCS1**/PrivateKeyInfo pkInfo =PrivateKeyInfo.getInstance(privKeyInfo.getEncoded());ASN1Encodable encodable = pkInfo.parsePrivateKey();ASN1Primitive primitive = encodable.toASN1Primitive();byte[] privateKeyPKCS1 = primitive.getEncoded();/**将PKCS1中的私钥转换为PEM**/PemObject pemObject =newPemObject("RSA PRIVATE KEY", privateKeyPKCS1);try(StringWriter stringWriter =newStringWriter()){PemWriter pemWriter =newPemWriter(stringWriter);
            pemWriter.writeObject(pemObject);
            pemWriter.flush();String pemString = stringWriter.toString();File pem =newFile(pkcs1KeyFilePath, pkcs1KeyFileName);FileUtils.writeStringToFile(pem, pemString, CHARSET);return pem;}}

pkcs1私钥转pkcs8私钥

方法1：使用OpenSSL工具转化

openssl pkcs8 -topk8 -inform PEM -in rsa_private_key_pkcs1.pem -outform PEM -out rsa_private_key_pkcs8.pem -nocrypt

命令执行完后，当前文件目录下将会出现一个名为

rsa_private_key_pkcs8.pem

的文件，即为pkcs8格式。

方法2：通过代码实现

jar包版本

<dependency><groupId>org.bouncycastle</groupId><artifactId>bcpkix-jdk18on</artifactId><version>1.72</version></dependency>

代码如下

privatestaticfinalString CHARSET ="utf-8";/***
    静态代码块创建Bouncy Castle提供者
    */static{org.bouncycastle.jce.provider.BouncyCastleProvider provider =neworg.bouncycastle.jce.provider.BouncyCastleProvider();Security.addProvider(provider);}/**
     * pkcs1私钥转化为pkcs8私钥
     * @param pkcs1Key
     * @param pkcs8KeyFilePath
     * @param pkcs8KeyFileName
     * @return
     * @throws Exception
     */publicstaticFileformatPkcs1ToPkcs8(File pkcs1Key,String pkcs8KeyFilePath,String pkcs8KeyFileName)throwsException{PemObject object =null;try(PemReader pemReader =newPemReader(newFileReader(pkcs1Key))){
            object =  pemReader.readPemObject();}PrivateKey privKeyInfo =KeyFactory.getInstance("RSA").generatePrivate(newPKCS8EncodedKeySpec(object.getContent()));/**将PKCS8中的私钥转换为PEM**/PemObject pemObject =newPemObject("PRIVATE KEY", privKeyInfo.getEncoded());try(StringWriter stringWriter =newStringWriter()){PemWriter pemWriter =newPemWriter(stringWriter);
            pemWriter.writeObject(pemObject);
            pemWriter.flush();String pemString = stringWriter.toString();File pem =newFile(pkcs8KeyFilePath, pkcs8KeyFileName);FileUtils.writeStringToFile(pem, pemString, CHARSET);return pem;}}

方法3：通过第三方工具集hutool实现

hutool在

5.8.5

版本已经提供对pkcs#1格式秘钥的支持。

jar版本

<dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId><version>5.8.8</version></dependency><dependency><groupId>org.bouncycastle</groupId><artifactId>bcpkix-jdk18on</artifactId><version>1.72</version></dependency>

代码如下

privatestaticfinalString CHARSET ="utf-8";/**
     * pkcs1私钥转化为pkcs8私钥
     * @param pkcs1Key
     * @param pkcs8KeyFilePath
     * @param pkcs8KeyFileName
     * @return
     * @throws Exception
     */publicstaticFileformatPkcs1ToPkcs8ByHutool(File pkcs1Key,String pkcs8KeyFilePath,String pkcs8KeyFileName)throwsException{PrivateKey privKeyInfo =PemUtil.readPemPrivateKey(newFileInputStream(pkcs1Key));/**将PKCS8中的私钥转换为PEM**/PemObject pemObject =newPemObject("PRIVATE KEY", privKeyInfo.getEncoded());try(StringWriter stringWriter =newStringWriter()){PemWriter pemWriter =newPemWriter(stringWriter);
            pemWriter.writeObject(pemObject);
            pemWriter.flush();String pemString = stringWriter.toString();File pem =newFile(pkcs8KeyFilePath, pkcs8KeyFileName);FileUtils.writeStringToFile(pem, pemString, CHARSET);return pem;}}