java.io.IOException: 解密子字符串时最终确定密码时出错

Question

我运行遇到了一个问题，我不确定正确的解决方法。我用这个线程作为参考：

基本上我将一个字符串分成块并加密每个块。但是当需要以同样的方式解密时，它永远不会起作用。它总是给我这个烦人的异常：

"java.io.IOException: Error while finalizing cipher"

基本上我将字符串拆分如下：

static public class RSAString {
    private ArrayList<String> mChunkList = new ArrayList<String>();
    RSAString() {
        mChunkList.clear();
    }
    public ArrayList<String> getChunkList() {
        return mChunkList;
    }
    RSAString(String stringSrc) {
        if (stringSrc.length() < CHUNK_SIZE) {
            mChunkList.add(stringSrc);
        } else {
            int j = 0;
            for (int i = 0; i < stringSrc.length() / CHUNK_SIZE; i++) {
                String subString = stringSrc.substring(j, j + CHUNK_SIZE);
                mChunkList.add(subString);
                j += CHUNK_SIZE;
            }
            int leftOver = stringSrc.length() % CHUNK_SIZE;
            if (leftOver > 0) {
                String subString = stringSrc.substring(j, j + leftOver);
                mChunkList.add(subString);
            }
        }
    }
}

然后我用这个密码解密：

// This **DOES NOT** work
final String AndroidOpenSSLString = "AndroidOpenSSL";
final String AndroidKeyStoreBCWorkaroundString = "AndroidKeyStoreBCWorkaround";
mProvider = Build.VERSION.SDK_INT < Build.VERSION_CODES.M ? AndroidOpenSSLString : AndroidKeyStoreBCWorkaroundString;
Cipher outCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", mProvider);
outCipher.init(Cipher.DECRYPT_MODE, mPrivateKey);
for (String chunkEncrypted : rsaEcryptedText.getChunkList()) {
    byte[] cipherText = chunkEncrypted.getBytes("UTF-8");
    CipherInputStream cipherInputStream = new CipherInputStream(
            new ByteArrayInputStream(Base64.decode(cipherText, Base64.NO_WRAP)), outCipher);
    ArrayList<Byte> values = new ArrayList<>();
    int nextByte;
    while ((nextByte = cipherInputStream.read()) != -1) {
        values.add((byte) nextByte);
    }
    byte[] bytes = new byte[values.size()];
    for (int i = 0; i < bytes.length; i++) {
        bytes[i] = values.get(i);
    }
    decryptedString += new String(bytes, 0, bytes.length, "UTF-8");
    cipherInputStream.close();
    cipherInputStream.reset();
}

我发现的唯一解决方法是在每个新的子字符串中重新初始化密码。喜欢下面的技巧：

for (String chunkEncrypted : rsaEcryptedText.getChunkList()) {
    // This works, but I am re-initializing the out cypher every time!
    // super slow!!! WHY DO I HAVE TO DO THIS?
    Cipher outCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", mProvider);
    outCipher.init(Cipher.DECRYPT_MODE, mPrivateKey);
    byte[] cipherText = chunkEncrypted.getBytes("UTF-8");
    CipherInputStream cipherInputStream = new CipherInputStream(
            new ByteArrayInputStream(Base64.decode(cipherText, Base64.NO_WRAP)), outCipher);
    ArrayList<Byte> values = new ArrayList<>();
    int nextByte;
    while ((nextByte = cipherInputStream.read()) != -1) {
        values.add((byte) nextByte);
    }
    byte[] bytes = new byte[values.size()];
    for (int i = 0; i < bytes.length; i++) {
        bytes[i] = values.get(i);
    }
    decryptedString += new String(bytes, 0, bytes.length, "UTF-8");
    cipherInputStream.close();
    cipherInputStream.reset();
}

我的修复程序的问题是它使解密速度变慢。此外，即使我的子字符串尺寸较小（子字符串 int CHUNK_SIZE = 64），我仍然遇到相同的异常。

无论如何，我不知道是否有人能指出我用 RSA 加密解密长字符串的正确方法。

这是加密代码——不确定它在这种情况下是否重要——但它总是有效的：

Cipher inCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", mProvider);
inCipher.init(Cipher.ENCRYPT_MODE, mPublicKey);
RSAString rsaStringPlainText = new RSAString(plainText);
for (String chunkPlain : rsaStringPlainText.getChunkList()) {
    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
    CipherOutputStream cipherOutputStream = new CipherOutputStream(
            outputStream, inCipher);
    cipherOutputStream.write(chunkPlain.getBytes("UTF-8"));
    cipherOutputStream.flush();
    cipherOutputStream.close();
    byte[] ecryptedText = Base64.encode(outputStream.toByteArray(), Base64.NO_WRAP);
    encryptedStringOut.mChunkList.add(new String(ecryptedText));
}

Answer 1

RSA 不适合批量加密，因为它非常慢（与 AES 相比超过 1000 倍）。如果可以，请改用 AES 等对称加密算法。如果您需要 RSA 的两个密钥，请使用 Hybrid 加密，其中您使用随机对称密钥加密数据，然后使用 RSA 加密该密钥键。

对称加密的另一个好处是库自动支持批量加密，您无需在加密前将数据分成小块。

java.io.IOException: 解密子字符串时最终确定密码时出错

java.io.IOException: Error while finalizing cipher while decrypting sub-strings

encryption

android-keystore