从String到java.Security.PublicKey对象向我提供了一个非法字符

Question

我有这个方法：

public static PublicKey getKey(String key){
    try{
        byte[] byteKey = Base64.getDecoder().decode(key.getBytes());
        X509EncodedKeySpec X509publicKey = new X509EncodedKeySpec(byteKey);
        KeyFactory kf = KeyFactory.getInstance("RSA");

        return kf.generatePublic(X509publicKey);
    }
    catch(Exception e){
        e.printStackTrace();
    }

        return null;
    }
}

getKey("pTSWJvy04hAU7ev7wmaTvpwHsEbseuPl0AlwoxPHnmoOIMATRT0eTqYpLJxDp4BHRFxDTrcUKHKVHGIAVut_-l6nkEI6ALOVW9C5PP9bXwqeHJ5tiGA6AMpaY1LsJJOd2lgExr0LHUPF2TtO4LOVmlptyGPTRSWhmRpPSc5bjGFsyTFr78WmeixjEts9icAUCiBDdpwVw9qVdjJPsufyimqp8os5htm-DB_qKsnRwABVSQRKLw2y7Mr7NP31R07Mpr108dLS5Et8tKnFoiX0MHf5BbA50NG3DtyT27nSa14T0IvSWYJQhxPWXYtuXkVldpbZZn8E2B1VpcDXXGnSPXoPstE9BU7w1RaF31UeEsE8sWDFdHgJMUYMfWjxVhdJB_NaVUt7v0X9QPffXcFPWKUUeVx0g_ONMz0bB_HltFSODWJeAvcZXk14u4sjpKXNIiK8dJzMe0Qn10m5nIdVtxzXfKHiDNobX1dMENDplhDMVk1eYS9x8dh90qt68Q59vKusm6iMjSaXtzwMfqJBwNck41e9Pie2m_cdSu-RIq1u3FScGkezzqNvIuzcse2y-6ApHkkaFMVsNw3CbD87LtVgNusuom38UVC1rS0LeLYFinU3hnFwvB1UCv1_0Cs8CmrOmdifqd25aZIDf5p8f3kowq3QY1mNtdQc9-HgZ3k");

我能做什么？我做错什么了？

Answer 1

您拥有的数据不是完整的RSA公钥，而是模数或“N”值。“e”值是公钥的另一部分。下面是代码片段来说明它。

import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.PublicKey;
import java.security.spec.RSAPublicKeySpec;
import java.util.Base64;

public class Main {

    public static void main(String[] args) throws Exception {
        String jsonN = "pTSWJvy04hAU7ev7wmaTvpwHsEbseuPl0AlwoxPHnmoOIMATRT0eTqYpLJxDp4BHRFxDTrcUKHKVHGIA" +
                "Vut_-l6nkEI6ALOVW9C5PP9bXwqeHJ5tiGA6AMpaY1LsJJOd2lgExr0LHUPF2TtO4LOVmlptyGPTRSWhmRpPSc5" +
                "bjGFsyTFr78WmeixjEts9icAUCiBDdpwVw9qVdjJPsufyimqp8os5htm-DB_qKsnRwABVSQRKLw2y7Mr7NP31R0" +
                "7Mpr108dLS5Et8tKnFoiX0MHf5BbA50NG3DtyT27nSa14T0IvSWYJQhxPWXYtuXkVldpbZZn8E2B1VpcDXXGnSP" +
                "XoPstE9BU7w1RaF31UeEsE8sWDFdHgJMUYMfWjxVhdJB_NaVUt7v0X9QPffXcFPWKUUeVx0g_ONMz0bB_HltFSO" +
                "DWJeAvcZXk14u4sjpKXNIiK8dJzMe0Qn10m5nIdVtxzXfKHiDNobX1dMENDplhDMVk1eYS9x8dh90qt68Q59vKu" +
                "sm6iMjSaXtzwMfqJBwNck41e9Pie2m_cdSu-RIq1u3FScGkezzqNvIuzcse2y-6ApHkkaFMVsNw3CbD87LtVgNu" +
                "suom38UVC1rS0LeLYFinU3hnFwvB1UCv1_0Cs8CmrOmdifqd25aZIDf5p8f3kowq3QY1mNtdQc9-HgZ3k";
        String jsonE = "AQAB";

        byte [] nBytes = Base64.getUrlDecoder().decode(jsonN);
        byte [] eBytes = Base64.getUrlDecoder().decode(jsonE);

        BigInteger n = new BigInteger(1, nBytes); // need to use the sign-magnitude constructor
        BigInteger e = new BigInteger(1, eBytes);

        RSAPublicKeySpec rsaPublicKeySpec = new RSAPublicKeySpec(n, e);
        KeyFactory rsaKeyFactory = KeyFactory.getInstance("RSA");
        PublicKey rsaPub = rsaKeyFactory.generatePublic(rsaPublicKeySpec);
        System.out.println(rsaPub);
    }
}

我将寻找一个已经完成此操作的库，而不是手工完成此操作，尽管库的建议与StackOverflow无关。