我有私人PEM密钥文件，我使用签名的文件和数据加密。签名工作正常，我也能够验证另一个平台，但同时对数据进行加密，我收到以下错误：

I have private pem key file, I am using that file for signing and encrypting the data. Signing works fine and I am also able to verify on another platform, but while encrypting the data, I am getting the following the error:

04-04 09:55:51.821: E/AndroidRuntime(2725): FATAL EXCEPTION: Thread-102
04-04 09:55:51.821: E/AndroidRuntime(2725): java.lang.ArrayIndexOutOfBoundsException: too much data for RSA block
04-04 09:55:51.821: E/AndroidRuntime(2725):     at com.android.org.bouncycastle.jce.provider.JCERSACipher.engineDoFinal(JCERSACipher.java:457)
04-04 09:55:51.821: E/AndroidRuntime(2725):     at javax.crypto.Cipher.doFinal(Cipher.java:1106)
04-04 09:55:51.821: E/AndroidRuntime(2725):     at com.example.testsigning.MainActivity.rsaEncrypt(MainActivity.java:185)
04-04 09:55:51.821: E/AndroidRuntime(2725):     at com.example.testsigning.MainActivity$1.run(MainActivity.java:51)
04-04 09:55:51.821: E/AndroidRuntime(2725):     at java.lang.Thread.run(Thread.java:856)

以下是code片段中提取私人文件密钥：

Following is the code snippet to extract keys from private file:

// Read the file into string
String privKeyPEM = readFile("/mnt/sdcard/rsa_key");

privKeyPEM = privKeyPEM.replace("-----BEGIN RSA PRIVATE KEY-----", "");
privKeyPEM = privKeyPEM.replace("-----END RSA PRIVATE KEY-----", "");

// Base64 decode the data
byte[] encoded = Base64.decode(privKeyPEM, Base64.DEFAULT);

// PKCS8 decode the encoded RSA private key
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(encoded);
KeyFactory kf = KeyFactory.getInstance("RSA");
mPrivKey = kf.generatePrivate(keySpec);

RSAPrivateCrtKey privk = (RSAPrivateCrtKey) mPrivKey;

RSAPublicKeySpec pubKeySpec = new java.security.spec.RSAPublicKeySpec(
        privk.getPublicExponent(), privk.getModulus());

mPubKey = kf.generatePublic(pubKeySpec);

和以下是code段加密数据：

And following is the code snippet to encrypt the data:

Cipher cipher = Cipher.getInstance("RSA/None/OAEPWithSHA1AndMGF1Padding", "BC");
cipher.init(Cipher.ENCRYPT_MODE, mPubKey);
return cipher.doFinal("Hello World".getBytes()); // here is the problem

任何帮助解决这一问题将是非常美联社preciated。

Any help to resolve the issue would be highly appreciated.

问候，Yuvi

Regards, Yuvi

推荐答案

这个问题是从检索私有密钥的公共密钥，它应该是这样的：

The problem was in retrieving the public key from private key, It should be like this:

RSAPublicKeySpec pubKeySpec = new java.security.spec.RSAPublicKeySpec(
                privk.getModulus(), privk.getPublicExponent());

而不是：

RSAPublicKeySpec pubKeySpec = new java.security.spec.RSAPublicKeySpec(
        privk.getPublicExponent(), privk.getModulus());