最近在逆向某Android App的时候复制了里面一段Java写的RSA解密代码，把它放在Windows上执行，结果发现解密失败，刚开始以为是密文数据或者公钥数据弄错了，调试了下发现密文数据或者公钥数据都没问题，问题发生在通过公钥数据生成公钥，在Window上生成的公钥是Sun RSA public key，在Android上生成的公钥是OpenSSLRSAPublicKey，原因可能和Jdk版本有关系：Window上使用的是SunJdk，Android上使用的是OpenJdk。

Windows：

public class ExampleUnitTest {

@Test

public void testGetPublicKey() {

try{

KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");

keyPairGenerator.initialize(1024);

KeyPair keyPair = keyPairGenerator.generateKeyPair();

RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();

System.out.println(publicKey);

}catch (Exception e){

}

}

}

Sun RSA public key, 1024 bits

modulus: 95213884349438225170527524041975750351683444678161946275254426695337973208253569775466173664279298747653058061430975492241277502919945076896996944444736550396126983267986003483379392361465058231916774917978538137429201243314904997369770567867017186086453893426267549310093584324574550363215845297101263978509

public exponent: 65537

Android：

public class ExampleInstrumentedTest {

@Test

public void testGetPublicKey() {

try{

KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");

keyPairGenerator.initialize(1024);

KeyPair keyPair = keyPairGenerator.generateKeyPair();

RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();

Log.d("Test", "testGetPublicKey: "+publicKey);

}catch (Exception e){

}

}

}

testGetPublicKey: OpenSSLRSAPublicKey{modulus=cbeecbec35b18cde50f2f201e441f5d9b57dacb2ba780a2f93152295d7661e822a570035e55217234d3f6070794faf28d5c3975fd62e1cfbf714cd379c8ee2166544a555e3f89c0be9074f8acccced9a9e1a8071a6c30abeea3bc5c8565dd34fd34794da50cb74e68c5f93e9f0925b60f87c89aacb25a9e357fd819ef0cf5a11,publicExponent=10001}