我一直在尝试创建一个java.security.PublicKey使用 Base64 编码的 ECC 公钥的实例。
MainActivity.java
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
try {
byte[] data = decodePublicKey("AsIAEFjzIcX+Kvhe8AmLoGUc8aYAEAwf5ecREGZ2u4RLxQuav/A=");
PublicKey publicKey = loadPublicKey("secp128r1", data);
Log.d(TAG, publicKey.toString());
} catch (SQLException | IOException | GeneralSecurityException e) {
Log.e(TAG, e.getMessage(), e);
}
}
private byte[] decodePublicKey(String s) throws UnsupportedEncodingException {
return Base64.decode(s, Base64.DEFAULT);
}
public PublicKey loadPublicKey(String curve, byte[] data)
throws SQLException, IOException, GeneralSecurityException {
Log.d(TAG, Arrays.toString(data));
// [2, -62, 0, 16, 88, -13, 33, -59, -2, 42, -8, 94, -16, 9, -117, -96, 101, 28, -15, -90, 0, 16, 12, 31, -27, -25, 17, 16, 102, 118, -69, -124, 75, -59, 11, -102, -65, -16]
Log.d(TAG, "Length :" + String.valueOf(data.length));
KeyFactory factory = KeyFactory.getInstance("EC", "SC");
ECNamedCurveParameterSpec spec = ECNamedCurveTable.getParameterSpec(curve);
ECCurve eccCurve = spec.getCurve();
Log.d(TAG, "Curve: " + curve);
EllipticCurve ellipticCurve = EC5Util.convertCurve(eccCurve, spec.getSeed());
// decoding point fails,
// line no 66.
ECPoint point = ECPointUtil.decodePoint(ellipticCurve, data);
ECParameterSpec params = EC5Util.convertSpec(ellipticCurve, spec);
ECPublicKeySpec keySpec = new ECPublicKeySpec(point, params);
return factory.generatePublic(keySpec);
}
日志猫：
Process: com.example.eccdemo, PID: 21151
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.eccdemo/com.example.eccdemo.MainActivity}: java.lang.IllegalArgumentException: Incorrect length for compressed encoding
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2329)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2389)
at android.app.ActivityThread.access$900(ActivityThread.java:147)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1296)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:898)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693)
Caused by: java.lang.IllegalArgumentException: Incorrect length for compressed encoding
at org.spongycastle.math.ec.ECCurve.decodePoint(ECCurve.java:349)
at org.spongycastle.jce.ECPointUtil.decodePoint(ECPointUtil.java:52)
at com.example.eccdemo.MainActivity.loadPublicKey(MainActivity.java:66)
at com.example.eccdemo.MainActivity.onCreate(MainActivity.java:45)
at android.app.Activity.performCreate(Activity.java:5933)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2282)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2389)
at android.app.ActivityThread.access$900(ActivityThread.java:147)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1296)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:898)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693)
进一步检查：
在 Logcat 中，在打印解码后的字节时，它们实际上与服务器上的不同：
Log.d(TAG, Arrays.toString(data));
[2, -62, 0, 16, 88, -13, 33, -59, -2, 42, -8, 94, -16, 9, -117, -96, 101, 28, -15, -90, 0, 16, 12, 31, -27, -25, 17, 16, 102, 118, -69, -124, 75, -59, 11, -102, -65, -16]
在 python 控制台中：
In [131]: [_ for _ in ap.public_key.tobytes()]
Out[131]: [2, 194, 0, 16, 88, 243, 33, 197, 254, 42, 248, 94, 240, 9, 139, 160, 101, 28, 241, 166, 0, 16, 12, 31, 229, 231, 17, 16, 102, 118, 187, 132, 75, 197, 11, 154, 191, 240]
如果有人可以解释这种异常的原因，并且还可以帮助我在小片段上PublicKey从字符串中获取实例，那就太好了。
参考：
http://www.programcreek.com/java-api-examples/index.php?api=org.bouncycastle.asn1.ASN1InputStream
http://www.bouncycastle.org/wiki/display/JA1/Elliptic+Curve+Key+Pair+Generation+and+Key+Factories
提前致谢！！
更新：
当尝试使用下面的行加载 ASN1Primitive 时，它会引发以下异常：
ASN1Primitive.fromByteArray(data);
例外：
java.io.IOException: DER length more than 4 bytes: 66
at org.spongycastle.asn1.ASN1InputStream.readLength(ASN1InputStream.java:347)
at org.spongycastle.asn1.ASN1InputStream.readLength(ASN1InputStream.java:112)
at org.spongycastle.asn1.ASN1InputStream.readObject(ASN1InputStream.java:237)
at org.spongycastle.asn1.ASN1Primitive.fromByteArray(ASN1Primitive.java:30)
at com.example.eccdemo.MainActivity.onCreate(MainActivity.java:48)
at android.app.Activity.performCreate(Activity.java:5933)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2282)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2389)
at android.app.ActivityThread.access$900(ActivityThread.java:147)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1296)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:898)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693)