Question

使用public_key.der进行加密可以完美无缺，但使用public_key.der进行解密则无法完成。已使用String通过我的服务器Java生成使用openssl解密的base64_encoded private_key.pem。

我收到一个LogCat错误：RSA块的数据太多。我很确定情况并非如此，因为private_key.pem的加密数据是文本“hello”。

这是我的MainActivity.class（应该与Java解密非常相似）

public class Main extends Activity {

    // Decrypt tester

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        String plainText = "hello";
        // Base64 Encoded
        String encryptedText = "SWfL6wpS87SsvByIfLO1W5Gg/gOMqtplNtqBrDELfQav0ipCy0BddHpTlmlgQO+6HRY2JWsw6hp5rlmmBJG722Ujc4Rm5MZr8BbKWMgX89rvmvUG/YeswTjHZsrzbx6k6krChM55dsJCU3JSXPMIcTTgRxVValgLeCfX1SwoOpNZ2m4WQAhX6NrSYwSXGLUHfrguQogTpU5wEcDQ0HR4vBlQO5fU8z2MwoP50Vs8f+4EysEwSy9ezsYHWDtW8M9t3EuF8Roq++/Y8GLASrYZxuAA0IPHGvR9Qufa04i7HlAAsDu9LQuOGUf35KkpFoCx0XyuA0qppccGdqHuK5IIoQ==";
        try {
            String encrypted = encrypt(getAssets().open("public_key.der"), plainText);
            Log.d("Encrypted", encrypted);
            // Returns a base64 encoded string.

            Log.d("TAG", "Decryption start");

            String decrypted = decrypt(getAssets().open("public_key.der"), encryptedText);
            Log.d("Decrypted", decrypted);
        } catch (Exception e) {
            Log.e("TEST", Log.getStackTraceString(e));
        }
    }

    public static String encrypt(InputStream stream, String plaintext) throws IOException, NoSuchAlgorithmException, InvalidKeySpecException,
            NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {

        byte[] encodedKey = new byte[stream.available()];
        stream.read(encodedKey);
        X509EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(encodedKey);
        KeyFactory kf = KeyFactory.getInstance("RSA");
        PublicKey pkPublic = kf.generatePublic(publicKeySpec);

        Cipher pkCipher = Cipher.getInstance("RSA/ECB/PKCS1PADDING");
        pkCipher.init(Cipher.ENCRYPT_MODE, pkPublic);
        byte[] encryptedInByte = pkCipher.doFinal(plaintext.getBytes());

        String encryptedInString = new String(Base64Coder.encode(encryptedInByte));

        return encryptedInString;
    }

    public static String decrypt(InputStream stream, String encrypted) throws IOException, NoSuchAlgorithmException, InvalidKeySpecException,
            NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {

        byte[] encodedKey = new byte[stream.available()];
        stream.read(encodedKey);
        X509EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(encodedKey);
        KeyFactory kf = KeyFactory.getInstance("RSA");
        PublicKey pkPublic = kf.generatePublic(publicKeySpec);

        Cipher pkCipher = Cipher.getInstance("RSA/ECB/PKCS1PADDING");
        pkCipher.init(Cipher.DECRYPT_MODE, pkPublic);
        byte[] decryptedInByte = pkCipher.doFinal(encrypted.getBytes());
        String decryptedInString = new String(Base64Coder.encode(decryptedInByte));
        return decryptedInString;
    }
}

这是我的Base64Decoder

public class Base64Coder {

    private static char[] map1 = new char[64];
    static {
        int i = 0;
        for (char c = 'A'; c <= 'Z'; c++)
            map1[i++] = c;
        for (char c = 'a'; c <= 'z'; c++)
            map1[i++] = c;
        for (char c = '0'; c <= '9'; c++)
            map1[i++] = c;
        map1[i++] = '+';
        map1[i++] = '/';
    }

    private static byte[] map2 = new byte[128];
    static {
        for (int i = 0; i < map2.length; i++)
            map2[i] = -1;
        for (int i = 0; i < 64; i++)
            map2[map1[i]] = (byte) i;
    }

    public static String encodeString(String s) {
        return new String(encode(s.getBytes()));
    }

    public static char[] encode(byte[] in) {
        return encode(in, in.length);
    }

    public static char[] encode(byte[] in, int iLen) {
        int oDataLen = (iLen * 4 + 2) / 3;
        int oLen = ((iLen + 2) / 3) * 4;
        char[] out = new char[oLen];
        int ip = 0;
        int op = 0;
        while (ip < iLen) {
            int i0 = in[ip++] & 0xff;
            int i1 = ip < iLen ? in[ip++] & 0xff : 0;
            int i2 = ip < iLen ? in[ip++] & 0xff : 0;
            int o0 = i0 >>> 2;
            int o1 = ((i0 & 3) << 4) | (i1 >>> 4);
            int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6);
            int o3 = i2 & 0x3F;
            out[op++] = map1[o0];
            out[op++] = map1[o1];
            out[op] = op < oDataLen ? map1[o2] : '=';
            op++;
            out[op] = op < oDataLen ? map1[o3] : '=';
            op++;
        }
        return out;
    }

    public static String decodeString(String s) {
        return new String(decode(s));
    }

    public static byte[] decode(String s) {
        return decode(s.toCharArray());
    }

    public static byte[] decode(char[] in) {
        int iLen = in.length;
        if (iLen % 4 != 0) throw new IllegalArgumentException("Length of Base64 encoded input string is not a multiple of 4.");
        while (iLen > 0 && in[iLen - 1] == '=')
            iLen--;
        int oLen = (iLen * 3) / 4;
        byte[] out = new byte[oLen];
        int ip = 0;
        int op = 0;
        while (ip < iLen) {
            int i0 = in[ip++];
            int i1 = in[ip++];
            int i2 = ip < iLen ? in[ip++] : 'A';
            int i3 = ip < iLen ? in[ip++] : 'A';
            if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127) throw new IllegalArgumentException("Illegal character in Base64 encoded data.");
            int b0 = map2[i0];
            int b1 = map2[i1];
            int b2 = map2[i2];
            int b3 = map2[i3];
            if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0) throw new IllegalArgumentException("Illegal character in Base64 encoded data.");
            int o0 = (b0 << 2) | (b1 >>> 4);
            int o1 = ((b1 & 0xf) << 4) | (b2 >>> 2);
            int o2 = ((b2 & 3) << 6) | b3;
            out[op++] = (byte) o0;
            if (op < oLen) out[op++] = (byte) o1;
            if (op < oLen) out[op++] = (byte) o2;
        }
        return out;
    }
}

这是Logcat输出。第82行是byte[] decryptedInByte = pkCipher.doFinal(encrypted.getBytes());

03-15 01:02:23.855: E/TEST(16749): java.lang.ArrayIndexOutOfBoundsException: too much data for RSA block
03-15 01:02:23.855: E/TEST(16749):  at com.android.org.bouncycastle.jce.provider.JCERSACipher.engineDoFinal(JCERSACipher.java:457)
03-15 01:02:23.855: E/TEST(16749):  at javax.crypto.Cipher.doFinal(Cipher.java:1111)
03-15 01:02:23.855: E/TEST(16749):  at com.example.testing.app.Main.decrypt(Main.java:82)
03-15 01:02:23.855: E/TEST(16749):  at com.example.testing.app.Main.onCreate(Main.java:46)
03-15 01:02:23.855: E/TEST(16749):  at android.app.Activity.performCreate(Activity.java:5163)
03-15 01:02:23.855: E/TEST(16749):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
03-15 01:02:23.855: E/TEST(16749):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2061)
03-15 01:02:23.855: E/TEST(16749):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2122)
03-15 01:02:23.855: E/TEST(16749):  at android.app.ActivityThread.access$600(ActivityThread.java:140)
03-15 01:02:23.855: E/TEST(16749):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1228)
03-15 01:02:23.855: E/TEST(16749):  at android.os.Handler.dispatchMessage(Handler.java:99)
03-15 01:02:23.855: E/TEST(16749):  at android.os.Looper.loop(Looper.java:137)
03-15 01:02:23.855: E/TEST(16749):  at android.app.ActivityThread.main(ActivityThread.java:4895)
03-15 01:02:23.855: E/TEST(16749):  at java.lang.reflect.Method.invokeNative(Native Method)
03-15 01:02:23.855: E/TEST(16749):  at java.lang.reflect.Method.invoke(Method.java:511)
03-15 01:02:23.855: E/TEST(16749):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:994)
03-15 01:02:23.855: E/TEST(16749):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:761)
03-15 01:02:23.855: E/TEST(16749):  at dalvik.system.NativeStart.main(Native Method)

public_key.pem

private_key.pem

Answer 1

我在解密方法中遇到了错误的调用。正确的电话如下......

public static String decrypt(InputStream stream, String encrypted) throws IOException, NoSuchAlgorithmException, InvalidKeySpecException,
        NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {

    byte[] encodedKey = new byte[stream.available()];
    stream.read(encodedKey);
    X509EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(encodedKey);
    KeyFactory kf = KeyFactory.getInstance("RSA");
    PublicKey pkPublic = kf.generatePublic(publicKeySpec);

    Cipher pkCipher = Cipher.getInstance("RSA/ECB/PKCS1PADDING");
    pkCipher.init(Cipher.DECRYPT_MODE, pkPublic);

    byte[] decoded = Base64Coder.decode(encrypted);
    byte[] decryptedInByte = pkCipher.doFinal(decoded);
    return new String(decryptedInByte);
}

执行RSA解密时出错

1 个答案: