问题描述
import android.os.Bundle;
import android.util.Base64;
import android.widget.Toast;
import org.bouncycastle.jce.provider.BouncyCastleProvider; // implementation 'org.bouncycastle:bcprov-jdk16:1.46'
import java.security.KeyFactory;
import java.security.PublicKey;
import java.security.Security;
import java.security.Signature;
import java.security.spec.X509EncodedKeySpec;
import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity {
static final String PUBLIC_KEY = "MFYwEAYHKoZIzj0CAQYFK4EEAAoDQgAEMEV3EPREEDc0t4MPeuYgreLMHMVfD7iYJ2Cnkd0ucwf3GYVySvYTttMVMNMEKF554NYmdrOlqwo2s8J2tKt/oQ==";
static final String DATA = "Hello";
static final String SIGNATURE = "MEUCIQCsuI4OcBAyA163kiWji1lb7xAtC8S0znf62EpdA+U4zQIgBcLbXtcuxXHcwQ9/DmiVfoiigKnefeYgpVXZzjIuYn8=";
static boolean verifyData() throws Exception {
PublicKey pk = getPublicKey();
byte[] signatureBytes = Base64.decode(SIGNATURE,Base64.NO_WRAP);
Signature signature = Signature.getInstance("SHA256withECDSA","BC");
signature.initVerify(pk);
signature.update(DATA.getBytes("UTF-8"));
return signature.verify(signatureBytes);
}
static PublicKey getPublicKey() throws Exception {
Security.addProvider(new BouncyCastleProvider());
KeyFactory keyFactory = KeyFactory.getInstance("EC","BC");
X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(Base64.decode(PUBLIC_KEY,Base64.NO_WRAP));
PublicKey key = keyFactory.generatePublic(x509EncodedKeySpec);
return key;
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
try {
Toast.makeText(this,verifyData() + "",Toast.LENGTH_LONG).show();
} catch (Exception e) {
Toast.makeText(this,"Failure: " + e.getMessage(),Toast.LENGTH_LONG).show();
e.printStackTrace();
}
}
}
上面的代码执行ECDSA数字签名验证。此代码在Android P以下的每个Android版本上均能正常工作。在Android P上,我会遇到此异常。
java.security.NoSuchAlgorithmException: The BC provider no longer provides an implementation for Signature.SHA1withRSA. Please see https://android-developers.googleblog.com/2018/03/cryptography-changes-in-android-p.html for more details.
因此,如here所述,我试图从这些语句中删除提供者参数,如下所示:
Signature signature = Signature.getInstance("SHA256withECDSA");
KeyFactory keyFactory = KeyFactory.getInstance("EC");
但是它没有解决问题?怎么来的?现在,我遇到了这个异常:
java.security.InvalidKeyException: com.android.org.conscrypt.OpenSSLX509CertificateFactory$ParsingException: Error parsing public key
可能的解决方案之一是将targetSdkVersion降低到27,但这还不够好。有更好的解决方案吗?
解决方法
我可以在机器上重现该问题(Android P,API级别28)。该问题的一种可能解决方案是在添加BC Provider之前删除预安装的版本:
Security.removeProvider("BC");
Security.addProvider(new BouncyCastleProvider());
或者:
Security.removeProvider("BC");
Security.insertProviderAt(new BouncyCastleProvider(),1);
此外,必须明确指定BC Provider:
KeyFactory keyFactory = KeyFactory.getInstance("EC","BC");
...
Signature signature = Signature.getInstance("SHA256withECDSA","BC");
在这个星座中,可以验证签名。
与较低的API级别相比,不同的行为可能与在Android P here中实现的有关BC Provider的更改有关。