java读取pem格式私钥_openssl生成RSA格式及pkcs1与pkcs8格式互相转换

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openssl简介

OpenSSL 是一个开源项目，其组成主要包括以下三个组件：

openssl：多用途的命令行工具
libcrypto：加密算法库
libssl：加密模块应用库，实现了ssl及tls

openssl可以实现：密钥证书管理、对称加密和非对称加密等，想了解更多搜索查看官网。接下来主要围绕openssl生成RSA格式及pkcs1与pkcs8格式互相转换。

配置RSA密钥

可以参考支付宝配置密钥：

https://docs.open.alipay.com/common/104740
如图：

生成命令使用说明：RSA密钥生成命令生成RSA私钥openssl>genrsa -out rsa_private_key.pem 1024生成RSA公钥openssl>rsa -in rsa_private_key.pem -pubout -out rsa_public_key.pem将RSA私钥转换成PKCS8格式openssl>pkcs8 -topk8 -inform PEM -in rsa_private_key.pem -outform PEM -nocrypt -out pkcs8.pem注意：“>”符号后面的才是需要输入的命令。

具体操作：
openssl默认使用的是PEM格式，经过base64。

生成pem格式的私钥：

openssl genrsa -out private_key.pem 1024

[root@VM_0_2_centos sign]# openssl genrsa -out private_key.pem 1024
Generating RSA private key, 1024 bit long modulus
............................++++++
..................................................++++++
e is 65537 (0x10001)
[root@VM_0_2_centos sign]# ls
private_key.pem
[root@VM_0_2_centos sign]# cat private_key.pem
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

生成公钥：

openssl rsa -in private_key.pem -pubout -out public_key.pem

[root@VM_0_2_centos sign]# openssl rsa -in private_key.pem -pubout -out public_key.pem
writing RSA key
[root@VM_0_2_centos sign]# ls
private_key.pem  public_key.pem
[root@VM_0_2_centos sign]# cat public_key.pem
-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDH2m9FfHSMZlT1t0PfQDCNHIzv
nbhq6+WlxEWTHETVKe3wHR/E7TgqIYVRU0M1X2Jb7AKtopqer2PqS+AnTC1dUWDt
xcYWdvIaYAgTEyhlvaEpX8kcg2TW+X1VfJuw02nbimfGPcRQFVrJW2UJkAuF3jVy
hy0wnfovclcEEPmaWwIDAQAB
-----END PUBLIC KEY-----

pkcs8格式私钥

某些语言需要pkcs8格式的私钥。（php就不需要了）
使用openssl将刚才生成的私钥转为pkcs#8格式：
openssl pkcs8 -topk8 -inform PEM -in private_key.pem -outform PEM -nocrypt -out private_key_pkcs8.pem

[root@VM_0_2_centos sign]# openssl pkcs8 -topk8 -inform PEM -in private_key.pem -outform PEM -nocrypt -out private_key_pkcs8.pem
[root@VM_0_2_centos sign]#
[root@VM_0_2_centos sign]#  ls
private_key.pem  private_key_pkcs8.pem  public_key.pem
[root@VM_0_2_centos sign]# cat private_key_pkcs8.pem
-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----

pkcs1与pkcs8格式互相转换

传统私钥格式转PKCS8在文中上面已经给出，这里主要是PKCS8格式私钥转换为PKCS1（传统私钥格式）
命令：openssl rsa -in pkcs8.pem -out pri_key.pem

[root@VM_0_2_centos sign]# openssl rsa -in private_key_pkcs8.pem -out pri_key.pem
writing RSA key
[root@VM_0_2_centos sign]# cat pri_key.pem
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
[root@VM_0_2_centos sign]#

根据结果可知和上面生成的私钥是一致的

加解密demo代码

PHP版

<?php 
$pri = "-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----";$pub = "-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDH2m9FfHSMZlT1t0PfQDCNHIzv
nbhq6+WlxEWTHETVKe3wHR/E7TgqIYVRU0M1X2Jb7AKtopqer2PqS+AnTC1dUWDt
xcYWdvIaYAgTEyhlvaEpX8kcg2TW+X1VfJuw02nbimfGPcRQFVrJW2UJkAuF3jVy
hy0wnfovclcEEPmaWwIDAQAB
-----END PUBLIC KEY-----";$data = "message";echo "n<br/>n";
openssl_public_encrypt($data, $crypted, $pub);
echo base64_encode($crypted);echo "n<br/>n";openssl_private_decrypt($crypted, $decrypted, $pri);
echo $decrypted;
?>

Java版

import java.security.KeyFactory;
import java.security.PublicKey;import sun.misc.*;import java.security.PrivateKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;import javax.crypto.Cipher;import sun.misc.BASE64Decoder;public class TestRSA {public static String PRIVATE_KEY = "-----BEGIN RSA PRIVATE KEY-----" + "n" +"MIICXAIBAAKBgQCd3V5+GjpOwqNks9ProDGaZT2qURAAuAodHcUM3P1mnhOh4l4u" + "n" +"VdvkXunUI7K6XDg6Xu9eL1WDQc6qKXs/OD91LS+RpkIAb2gMU8hGrNfR34izZh36" + "n" +"KdfWnEQpniAiFsHsg2ddAaPtGZZ8/jpjuPq32IVZJkgyKcWqnz5aL3FMXQIDAQAB" + "n" +"AoGAJFdkvGTvTVhTYwhe3dxn7uIlmwLES1YSxfcneLmbADedz2OcSNBtKZqL+9Eo" + "n" +"AOzf6NgYBLei2O+aUuPvwnMBcGyijFmRoZGVEj70UP0mngyAkvY/juA60QDe5kY5" + "n" +"rsqj4raHUf4iDK85nNwzXu7hIlPAn+ZmH+e2Eekwo1rmgQUCQQDJerucfBKk3qrV" + "n" +"xS5NRW99lKMomIsMH55Si+rbrnk8aU3SSRSD6uil3Dytv0erLZbc9d0Nr6SmBZgO" + "n" +"0qzOjXDDAkEAyJVGgHMNuMbpHnim93HAP7wcejmMx7rP4zutw4OCiHrWv3kN8WUC" + "n" +"u826taRFtOuiXhQ3X8+tb0l4ifae+vJ8XwJAEcmuKqChnMCz4G+qKNRKhZHL3dep" + "n" +"3wYjmjIUKBT9SyIY5sng78ybgZkyGjza/Pfna9ahD4ZESQwRYq2i6BGAtQJBAJyD" + "n" +"bmnYXQKro0e1mYNHbV3OKOJueZ139bM35BTFT1uzjlIF4Y1U5lco5uHJduL/YsjK" + "n" +"OZM3d/t4duggWlkyUT0CQBdsjc7eQ9roxphrW4Q/6Zwi0EQ4xxM4SgxPY1RvkKFu" + "n" +"i0HdYBj5KRdIbrAbisUyQeKzB7+6oTJH5+kZAU/pxao=" + "n" +"-----END RSA PRIVATE KEY-----";public static String PRIVATE_KEY_PKCS8 = "-----BEGIN PRIVATE KEY-----" + "n" +"MIICdgIBADANBgkqhkiG9w0BAQEFAASCAmAwggJcAgEAAoGBAJ3dXn4aOk7Co2Sz" + "n" +"0+ugMZplPapREAC4Ch0dxQzc/WaeE6HiXi5V2+Re6dQjsrpcODpe714vVYNBzqop" + "n" +"ez84P3UtL5GmQgBvaAxTyEas19HfiLNmHfop19acRCmeICIWweyDZ10Bo+0Zlnz+" + "n" +"OmO4+rfYhVkmSDIpxaqfPlovcUxdAgMBAAECgYAkV2S8ZO9NWFNjCF7d3Gfu4iWb" + "n" +"AsRLVhLF9yd4uZsAN53PY5xI0G0pmov70SgA7N/o2BgEt6LY75pS4+/CcwFwbKKM" + "n" +"WZGhkZUSPvRQ/SaeDICS9j+O4DrRAN7mRjmuyqPitodR/iIMrzmc3DNe7uEiU8Cf" + "n" +"5mYf57YR6TCjWuaBBQJBAMl6u5x8EqTeqtXFLk1Fb32UoyiYiwwfnlKL6tuueTxp" + "n" +"TdJJFIPq6KXcPK2/R6stltz13Q2vpKYFmA7SrM6NcMMCQQDIlUaAcw24xukeeKb3" + "n" +"ccA/vBx6OYzHus/jO63Dg4KIeta/eQ3xZQK7zbq1pEW066JeFDdfz61vSXiJ9p76" + "n" +"8nxfAkARya4qoKGcwLPgb6oo1EqFkcvd16nfBiOaMhQoFP1LIhjmyeDvzJuBmTIa" + "n" +"PNr89+dr1qEPhkRJDBFiraLoEYC1AkEAnINuadhdAqujR7WZg0dtXc4o4m55nXf1" + "n" +"szfkFMVPW7OOUgXhjVTmVyjm4cl24v9iyMo5kzd3+3h26CBaWTJRPQJAF2yNzt5D" + "n" +"2ujGmGtbhD/pnCLQRDjHEzhKDE9jVG+QoW6LQd1gGPkpF0husBuKxTJB4rMHv7qh" + "n" +"Mkfn6RkBT+nFqg==" + "n" +"-----END PRIVATE KEY-----";public static String PUBLIC_KEY = "-----BEGIN PUBLIC KEY-----" + "n" +"MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCd3V5+GjpOwqNks9ProDGaZT2q" + "n" +"URAAuAodHcUM3P1mnhOh4l4uVdvkXunUI7K6XDg6Xu9eL1WDQc6qKXs/OD91LS+R" + "n" +"pkIAb2gMU8hGrNfR34izZh36KdfWnEQpniAiFsHsg2ddAaPtGZZ8/jpjuPq32IVZ" + "n" +"JkgyKcWqnz5aL3FMXQIDAQAB" + "n" +"-----END PUBLIC KEY-----";public static void main(String[] args) {String text = "message";try {String priStr = PRIVATE_KEY_PKCS8.replaceAll("-----BEGIN PRIVATE KEY-----n", "");priStr = priStr.replaceAll("-----END PRIVATE KEY-----", "");byte [] privateKeyBytes = new BASE64Decoder().decodeBuffer(priStr);PKCS8EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(privateKeyBytes);KeyFactory keyFactory = KeyFactory.getInstance("RSA");PrivateKey privateKey = keyFactory.generatePrivate(privateKeySpec);Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.ENCRYPT_MODE, privateKey);byte[] crypted = cipher.doFinal(text.getBytes());System.out.println(new BASE64Encoder().encode(crypted));//  decrypt blow.String pubStr = PUBLIC_KEY.replaceAll("-----BEGIN PUBLIC KEY-----n", "");pubStr = pubStr.replaceAll("-----END PUBLIC KEY-----", "");byte [] publicKeyBytes = new BASE64Decoder().decodeBuffer(pubStr);X509EncodedKeySpec  pubKeySpec = new X509EncodedKeySpec(publicKeyBytes);keyFactory = KeyFactory.getInstance("RSA");PublicKey publicKey = keyFactory.generatePublic(pubKeySpec);cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.DECRYPT_MODE, publicKey);byte[] bytes = cipher.doFinal(crypted);System.out.println(new String(bytes, "ISO-8859-1"));} catch (Exception e) {e.printStackTrace();}}}

需要注意的是，java的代码中的private key必须使用pkcs#8格式的。java加密,php解密也是没问题的！

感谢大家的阅读，也希望能转发并关注我的公众号（帝都小崔Cayden）或搜索code_cayden！