无法将 WebCrypto 密钥对转换为 Java RSA 密钥

Posted 2023-03-28

【中文标题】无法将 WebCrypto 密钥对转换为 Java RSA 密钥

【英文标题】：Unable to convert a WebCrypto key pair to Java RSA keys

【发布时间】：2018-07-16 06:38:19

【问题描述】：

我有公钥和私钥作为字符串，它们是从 Webcrypto API RSA-OAEP 算法。我想加密和解密一些 通过使用这些纯文本并在尝试转换时出现异常 字符串转字节数组

Java 代码：

package mailsend;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Security;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

import javax.crypto.Cipher;

public class RsaOaep 
  public static void main(String[] args) throws Exception 
    Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

    //Encryption
    byte[] input = "\"userid\":\"1242\",\"appid\":\"1234\",\"tenentid\":\"4567\",\"sessionid\":\"session1234567\"".getBytes();
    Cipher cipher = Cipher.getInstance("RSA/None/OAEPWithSHA1AndMGF1Padding", "BC");
    SecureRandom random = new SecureRandom();
    String publicKey="\n" + 
            "  \"alg\": \"RSA-OAEP-256\",\n" + 
            "  \"e\": \"AQAB\",\n" + 
            "  \"ext\": true,\n" + 
            "  \"key_ops\": [\n" + 
            "    \"encrypt\"\n" + 
            "  ],\n" + 
            "  \"kty\": \"RSA\",\n" + 
            "  \"n\": \"uChD48P6OBCynflLVsuP51hExmS7JIJmSPe6g_RYeb-O8rbaJA6mJE7QsMBeCrBUeyjhFYOFkGV9tpu3xIMkuRmTiyqy_mP2DKo8x9RB0gGVRvDuFjyOb3qpTAEA1SGyo_jGwN3RmVAVzVOTAAHqgQpRHtUsFEpQImUJgOUGVAfyFYpyyJKypcRv-RIU2JxOg3w7-i53erZPMHq_eWzEEXOgAU49UPjlTV18bXklBKSy3sbhKDpvHvOh_rEufhtD1Jl5RAQz3o8GGWPmcSf_3h5xa5ppqcgx6cfHDY9KKgxgCScwtjzTqU_QJO_zRnf3kYFU4dIFkfpXOJDDJc6RwQ\"\n" + 
            "";
    byte[] keyBytes = Base64.getDecoder().decode(publicKey);
    PublicKey publicKeyNew = KeyFactory.getInstance("RSA", "BC").generatePublic(new X509EncodedKeySpec(keyBytes));
    cipher.init(Cipher.ENCRYPT_MODE, publicKeyNew, random);
    byte[] cipherText = cipher.doFinal(input);
    System.out.println("cipher: " + new String(cipherText));

    //Decryption
    String privateKey="\n" + 
            "  \"alg\": \"RSA-OAEP-256\",\n" + 
            "  \"d\": \"FZO8Lp_r_a0xLHLE6cjElePg_QjY54Ry1RpXi3Xx9uPjrRsREJf5zffBGnCTpDd4Uozd4I4uNFa75c01eSwvfZOaVrw8SDOwpNe-cuBzDNbcJXl9v_O88aFi3DGi5hYCbxVrPjZPRGIeh9YCu4W98vwhOJZcCY2SeZEyjZxoAyjOmsvvylpUVN2ZVJ22lDOaBJMerPdwyXFv9wsUserFleZByk-M8WLz5JiT3MIg6NuMiMryx3-lhcHCBXgHJMeuxrdnPc_acer3WNkgWf5Q4LkTu9TT_Uz4kULtPvdbccv3-JyE0x4ZjCfiAmT65vUM5WvmCE6MZseR3WONIxmh0Q\",\n" + 
            "  \"dp\": \"FdzMUisoeG6Kk4C7Ol7k3QqR6QKa18LsMVIQXruQ7Vxm4bJ0lo8WyHWhLy4n11JLs7OGFENyXu7NtXw0ezmolfKIJVlItxWofICm8wm3Rhljrxe9KJnp1V4L1ibCXLOXOLsqhUwesWOhjAkfTHWJf3-wslSxVtFbif3fjeaKHlk\",\n" + 
            "  \"dq\": \"YTfHIEIOYiJ9AW_r3R8ou69ApwyzFNqczSeVooMKvKTYrpdj4ms6MeW5uL8Pq9HKFr8AFA2FWtOvrHrxShw_1V9IuvNChmPEF11RIO7CSc6xeK98zFtgqzbpJ81SKlcKh4icpaSjX3SQa7qbasgk9MBxK5gmpc5XZZNICDKfZ-E\",\n" + 
            "  \"e\": \"AQAB\",\n" + 
            "  \"ext\": true,\n" + 
            "  \"key_ops\": [\n" + 
            "    \"decrypt\"\n" + 
            "  ],\n" + 
            "  \"kty\": \"RSA\",\n" + 
            "  \"n\": \"uChD48P6OBCynflLVsuP51hExmS7JIJmSPe6g_RYeb-O8rbaJA6mJE7QsMBeCrBUeyjhFYOFkGV9tpu3xIMkuRmTiyqy_mP2DKo8x9RB0gGVRvDuFjyOb3qpTAEA1SGyo_jGwN3RmVAVzVOTAAHqgQpRHtUsFEpQImUJgOUGVAfyFYpyyJKypcRv-RIU2JxOg3w7-i53erZPMHq_eWzEEXOgAU49UPjlTV18bXklBKSy3sbhKDpvHvOh_rEufhtD1Jl5RAQz3o8GGWPmcSf_3h5xa5ppqcgx6cfHDY9KKgxgCScwtjzTqU_QJO_zRnf3kYFU4dIFkfpXOJDDJc6RwQ\",\n" + 
            "  \"p\": \"_8_ViZjqi4qU0jdt4dbrv81-FYFjJ0A3CpHhOwDxvIHRBMTS188_SEe-CZFwF91myv3AF9ZA64gYscr6t765F3-R7ydygryQWOedE-meRZhUHw3E3y-w_Khvtv0k3DW_NBO1-i3MDi8HV-xoSED9_ZYP6B0N05sBeoLhr76MuVk\",\n" + 
            "  \"q\": \"uErwgmSi7_t90oqKEED4Da8csEZVBN6_7n9xbZEk366lPf5rPETPbr8DKG-rA4kXq3l10ZksC-oo0RKdMpnqoHiYjmFPex1uLXJOAR_sg8ENtYtH-U6tNBjpoLufnbtg39O4bT7jr0HXx3MQmNy4rumfO97XypqIdKkrAODtJqk\",\n" + 
            "  \"qi\": \"brnAuBOvNKKdkwsI836lPNxmKqAMc-Jbtn7YmOu3ofq6PtiT5blJSGUJizMd1YDRHTLlQzWt1eqFZr_AjidGZ0QvYSj1jZT1hdpkIGn1M6oDDwh73mDC_Wqg5qtyFp6YudzWpSt5TG7m94pyPFx79wm1WedW53RVNQVdx3yOcBI\"\n" + 
            "";
    byte[] keyBytesNew = Base64.getDecoder().decode(privateKey);
    PrivateKey privateKeyNew = KeyFactory.getInstance("RSA", "BC").generatePrivate(new X509EncodedKeySpec(keyBytesNew));
    cipher.init(Cipher.DECRYPT_MODE, privateKeyNew);
    byte[] plainText = cipher.doFinal(cipherText);
    System.out.println("plain : " + new String(plainText));
  

例外：

线程“主”java.lang.IllegalArgumentException 中的异常： 非法 base64 字符 7b 在 java.util.Base64$Decoder.decode0(Base64.java:714) 在 java.util.Base64$Decoder.decode(Base64.java:526) 在 java.util.Base64$Decoder.decode(Base64.java:549) 在 mailsend.RsaOaep.main(RsaOaep.java:30)

【问题讨论】：

这可能会有所帮助 ***.com/questions/28584080/…>

你的publicKey字符串不在Base64中

我认为密钥被格式化为 JSON 网络令牌。找到合适的库来解析它们。

实际上我正在从 webcryptoAPI 获取导入的公钥和私钥，我无法在 java 公钥中映射 webcrypto 导入的公钥来解密一些纯文本

【参考方案1】：

webcrypto 导出的密钥是 JWK (JSON Web Key) 格式。 Java不直接支持这种格式，所以必须先处理RSA密钥对的组成部分

正确生成密钥后，您可以检查您的加密代码

1.解码 JSON Web Key：解析 JSON 字符串并提取公钥和私钥的组件

我建议使用像 Jackson 这样的 JSON 库。看到这个sample

public class JWK
    String n;
    String e;
    //getters and setters
 

ObjectMapper mapper = new ObjectMapper();
JWK jwk = mapper.readValue(publicKeyJson, JWK.class);

2。将关键组件转换为 BigInteger：模数、公共指数、私有指数等被编码为 base64url 字符串。将这些字符串解码为 byte[] 并使用它们构建 BigInteger，以便它们可以被 Java Key builder 加载

byte[] publicExponentBytes = Base64.getUrlDecoder().decode(jwkPublic.e);
byte[] privateExponentBytes = Base64.getUrlDecoder().decode(jwkPrivate.d);
byte[] modulusBytes = Base64.getUrlDecoder().decode(jwkPublic.n);

BigInteger publicExponent = new BigInteger(1, publicExponentBytes );
BigInteger privateExponent = new BigInteger(1, privateExponentBytes);
BigInteger modulus = new BigInteger(1, modulusBytes);

3.使用模数 (n) 和公共指数 (e) 构建公钥

RSAPublicKeySpec spec = new RSAPublicKeySpec(modulus, publicExponent );
KeyFactory factory = KeyFactory.getInstance("RSA");
PublicKey publicKey = factory.generatePublic(spec);

4.使用模数 (n) 和私有指数 (d) 构建私钥

RSAPrivateKeySpec privateKeySpec = new RSAPrivateKeySpec(modulus, privateExponent);
KeyFactory factory = KeyFactory.getInstance("RSA");
PrivateKey privateKey = factory.generatePrivate(privateKeySpec);

【讨论】：

我遵循了您建议的方法，谢谢。我在解密数据时遇到问题。我在这里发布了我的代码更改和异常

更正答案。私有指数是“d”，而不是“dP”