Java 读取 OpenSSL 生成的秘钥, 进行 RSA 加解密 | 数字魔法

> 本文由 [简悦 SimpRead](http://ksria.com/simpread/) 转码， 原文地址 [zxcsoft.com](https://zxcsoft.com/java/SpringBoot/2020-06-22.html#_2-2-pkcs1-%E7%A7%81%E9%92%A5%E8%BD%AC%E6%8D%A2%E4%B8%BA-pkcs8)

OpenSSL 生成的秘钥与 java RSA 加解密类生成的秘钥类型不一致, 导致加载秘钥失败. 通过引入一个工具包. 来实现加解密

1. 生成秘钥
-------

### 1.1 使用`OpenSSL`生成秘钥

```
openssl genrsa -out rsa_private_key.pem 1024
```

### 1.2 查看私钥

```
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
```

### 1.3 生成查看公钥

```
openssl rsa -in rsa_private_key.pem -out rsa_public_key_1024.pub -pubout
```

```
-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCtSXcCfb5pJ/CrOWDAdHVEO8wz
oj/Waskia3T9nBOXJKbf1TqTS7bn8m/2kn/bx0p8FuK+LcH2TeCNa5DXyCE+k+qk
qCXTI6U48aSKjzZ0eiCPRDm0ZfdCJoB3l7rxOx2jO/EXtjXC3VrX0vddjR/3AGDm
/TUmlIkm0IpHzdPSAwIDAQAB
-----END PUBLIC KEY-----
```

### 1.4 加解密引入包

```
<dependency>
      <groupId>org.bouncycastle</groupId>
      <artifactId>bcprov-jdk15on</artifactId>
      <version>1.56</version>
    </dependency>
```

### 1.5 加解密代码

```
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.codec.binary.Base64;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import javax.crypto.Cipher;
import java.nio.charset.StandardCharsets;
import java.security.KeyFactory;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.RSAPrivateKeySpec;
import java.security.spec.X509EncodedKeySpec;

@Component
@Slf4j
public class RSAUtil {

@Value("${config.rsa.privateKey}")
    private String privateKey;
    @Value("${config.rsa.publicKey}")
    private String publicKey;

public static void main(String[] args) {
        RSAUtil rsaUtil = new RSAUtil();
        rsaUtil.publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCtSXcCfb5pJ/CrOWDAdHVEO8wzoj/Waskia3T9nBOXJKbf1TqTS7bn8m/2kn/bx0p8FuK+LcH2TeCNa5DXyCE+k+qkqCXTI6U48aSKjzZ0eiCPRDm0ZfdCJoB3l7rxOx2jO/EXtjXC3VrX0vddjR/3AGDm/TUmlIkm0IpHzdPSAwIDAQAB";

rsaUtil.privateKey = "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";
        System.out.println(rsaUtil.encrypt("李四"));
        System.out.println(rsaUtil.encrypt("123456789012345678"));
        System.out.println("李四".equals(rsaUtil.decrypt(rsaUtil.encrypt("李四"))));
    }

public String encrypt(String str) {
        try {
            //base64编码的公钥
            byte[] decoded = Base64.decodeBase64(publicKey);
            RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
            //RSA加密
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.ENCRYPT_MODE, pubKey);
            return Base64.encodeBase64String(cipher.doFinal(str.getBytes(StandardCharsets.UTF_8)));
        } catch (Exception e) {
            log.error("encrypt failed: str[" + str + "], publicKey[" + publicKey + "]");
            throw new RunTimeException("解密失败", e);
        }
    }

public String decrypt(String str) {
        try {
            //64位解码加密后的字符串
            byte[] inputByte = Base64.decodeBase64(str.getBytes(StandardCharsets.UTF_8));
            //base64编码的私钥
            byte[] decoded = Base64.decodeBase64(privateKey);
            org.bouncycastle.asn1.pkcs.RSAPrivateKey rsaPrivateKey = org.bouncycastle.asn1.pkcs.RSAPrivateKey.getInstance(decoded);
            RSAPrivateKeySpec rsaPrivKeySpec = new RSAPrivateKeySpec(rsaPrivateKey.getModulus(), rsaPrivateKey.getPrivateExponent());
            RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(rsaPrivKeySpec);
            //RSA解密
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.DECRYPT_MODE, priKey);
            return new String(cipher.doFinal(inputByte));
        } catch (Exception e) {
            log.error("decrypt failed: str[" + str + "], privateKey[" + publicKey + "]", e);
            throw new RunTimeException("解密失败", e);
        }
    }
}
```

### 1.6 `RSA`秘钥类型说明

公钥加密标准（Public Key Cryptography Standards, PKCS）

<table><thead><tr><th>PKCS</th><th>版本</th><th>名称</th><th>简介</th></tr></thead><tbody><tr><td>PKCS #1 [^1]</td><td>2.1</td><td>RSA 密码编译标准（RSA Cryptography Standard）</td><td>定义了 RSA 的数理基础、公 / 私钥格式，以及加 / 解密、签 / 验章的流程。1.5 版本曾经遭到攻击。</td></tr><tr><td>PKCS #2</td><td>-</td><td>撤销</td><td>原本是用以规范 RSA 加密摘要的转换方式，现已被纳入 PKCS#1 之中。</td></tr><tr><td>PKCS #3</td><td>1.4</td><td>DH 密钥协议标准（Diffie-Hellman key agreement Standard）</td><td>规范以 DH 密钥协议为基础的密钥协议标准。其功能，可以让两方通过金议协议，拟定一把会议密钥 (Session key)。</td></tr><tr><td>PKCS #4</td><td>-</td><td>撤销</td><td>原本用以规范转换 RSA 密钥的流程。已被纳入 PKCS#1 之中。</td></tr><tr><td>PKCS #5</td><td>2.0</td><td>密码基植加密标准（Password-based Encryption Standard）</td><td>参见 RFC 2898 与 PBKDF2。</td></tr><tr><td>PKCS #6</td><td>1.5</td><td>证书扩展语法标准（Extended-Certificate Syntax Standard）</td><td>将原本 X.509 的证书格式标准加以扩充。</td></tr><tr><td>PKCS #7</td><td>1.5</td><td>密码消息语法标准（Cryptographic Message Syntax Standard）</td><td>参见 RFC 2315。规范了以公开密钥基础设施（PKI）所产生之签名 / 密文之格式。其目的一样是为了拓展数字证书的应用。其中，包含了 S/MIME 与 CMS。</td></tr><tr><td>PKCS #8 [^2]</td><td>1.2</td><td>私钥消息表示标准（Private-Key Information Syntax Standard）.</td><td>Apache 读取证书私钥的标准。</td></tr><tr><td>PKCS #9</td><td>2.0</td><td>选择属性格式（Selected Attribute Types）</td><td>定义 PKCS#6、7、8、10 的选择属性格式。</td></tr><tr><td>PKCS #10</td><td>1.7</td><td>证书申请标准（Certification Request Standard） 参见 RFC 2986。</td><td>规范了向证书中心申请证书之 CSR（certificate signing request）的格式。</td></tr><tr><td>PKCS #11</td><td>2.20</td><td>密码设备标准接口（Cryptographic Token Interface (Cryptoki)）</td><td>定义了密码设备的应用程序接口（API）之规格。</td></tr><tr><td>PKCS #12</td><td>1.0</td><td>个人消息交换标准（Personal Information Exchange Syntax Standard）</td><td>定义了包含私钥与公钥证书（public key certificate）的文件格式。私钥采密码 (password) 保护。常见的 PFX 就履行了 PKCS#12。</td></tr><tr><td>PKCS #13</td><td>–</td><td>椭圆曲线密码学标准（Elliptic curve cryptography Standard）</td><td>制定中。规范以椭圆曲线密码学为基础所发展之密码技术应用。椭圆曲线密码学是新的密码学技术，其强度与效率皆比现行以指数运算为基础之密码学算法来的优秀。然而，该算法的应用尚不普及。</td></tr><tr><td>PKCS #14</td><td>–</td><td>拟随机数产生器标准（Pseudo-random Number Generation）</td><td>制定中。规范拟随机数产生器的使用与设计。</td></tr><tr><td>PKCS #15</td><td>1.1</td><td>密码设备消息格式标准（Cryptographic Token Information Format Standard）</td><td>定义了密码</td></tr></tbody></table>

[^1]:`PKCS #1`为`OpenSSH`默认使用的加密标准 [^2]:`PKCS #8`为`Java`默认使用的加密标准

java 默认使用的 RSAKey

```
byte[] decoded = Base64.decodeBase64(publicKey);
RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
```

2 `RSA`格式转换
-----------

### 2.1 生成`PKCS1`私钥

`OpenSSL`生成`PKCS1`格式的私钥，密钥长度 1024 位

```
openssl genrsa -out private.pem 1024
```

### 2.2 `PKCS1`私钥转换为`PKCS8`

```
openssl pkcs8 -topk8 -inform PEM -in private.pem -outform pem -nocrypt -out pkcs8.pem
```

### 2.3 `PKCS8`私钥转换为`PKCS1`

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

### 2.4 从`PKCS1`私钥中生成`PKCS8`公钥

```
openssl rsa -in private.pem -pubout -out public.pem
```

### 2.5 从`PKCS8`私钥中生成`PKCS8`公钥

```
openssl rsa -in pkcs8.pem -pubout -out public_pkcs8.pem
```

与 2.4 生成的结果一致

### 2.6 从`PKCS8`公钥转换`PKCS1`公钥

```
openssl rsa -pubin -in public_pkcs8.pem -RSAPublicKey_out
```

生成前后文件一致

### 2.7 从`PKCS1`公钥转换`PKCS8`公钥

```
openssl rsa -RSAPublicKey_in -in pub_pkcs1.pem -pubout
```

生成前后文件一致