java javax.crypto.BadPaddingException：解密错误
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javax.crypto.BadPaddingException: Decryption error
提问by jenny kenith
Here is the error I have got when run my Encode & Decode Class.
这是我在运行编码和解码类时遇到的错误。
javax.crypto.BadPaddingException: Decryption error
at sun.security.rsa.RSAPadding.unpadV15(RSAPadding.java:380)
at sun.security.rsa.RSAPadding.unpad(RSAPadding.java:291)
at com.sun.crypto.provider.RSACipher.doFinal(RSACipher.java:365)
at com.sun.crypto.provider.RSACipher.engineDoFinal(RSACipher.java:391)
at javax.crypto.Cipher.doFinal(Cipher.java:2087)
at RSAEncDecDemo.decryptData(RSAEncDecDemo.java:64)
at RSAEncDecDemo.main(RSAEncDecDemo.java:47)
java.lang.NullPointerException
at java.lang.String.<init>(String.java:556)
at RSAEncDecDemo.decryptData(RSAEncDecDemo.java:70)
at RSAEncDecDemo.main(RSAEncDecDemo.java:47)
Here is the source code of RSAEncDecDemo.java class file.
这里是 RSAEncDecDemo.java 类文件的源代码。
public class RSAEncDecDemo {
private static final String PUBLIC_KEY_FILE = "lk.public.key";
private static final String PRIVATE_KEY_FILE = "lk.private.key";
@SuppressWarnings("restriction")
public static void main(String[] args) throws IOException {
try {
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
keyPairGenerator.initialize(2048);
KeyPair keyPair = keyPairGenerator.generateKeyPair();
PublicKey publicKey = keyPair.getPublic();
PrivateKey privateKey = keyPair.getPrivate();
writeStringkey(PUBLIC_KEY_FILE,new BASE64Encoder().encode(publicKey.getEncoded()));
writeStringkey(PRIVATE_KEY_FILE,new BASE64Encoder().encode(privateKey.getEncoded()));
String demoString = "123346";
RSAEncDecDemo rsa = new RSAEncDecDemo();
String decrypted = rsa.decryptData(demoString);
String msisdn = decrypted.substring(0,decrypted.indexOf("|"));
} catch (Exception e) {
e.printStackTrace();
}
}
private String decryptData(String strData) throws IOException {
byte[] data = DatatypeConverter.parseHexBinary(strData);
byte[] descryptedData = null;
try {
PrivateKey privateKey = readPrivateKeyFromFile(PRIVATE_KEY_FILE);
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
descryptedData = cipher.doFinal(data);
} catch (Exception e) {
e.printStackTrace();
}
return new String(descryptedData);
}
@SuppressWarnings("restriction")
public PrivateKey readPrivateKeyFromFile(String fileName)throws IOException, NoSuchAlgorithmException,InvalidKeySpecException {
String publicK = readStringKey(fileName);
byte[] keyBytes = new BASE64Decoder().decodeBuffer(publicK);
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory fact = KeyFactory.getInstance("RSA");
return fact.generatePrivate(keySpec);
}
public PrivateKey readPrivateKeyFromFileold(String fileName)throws IOException {
FileInputStream fis = null;
ObjectInputStream ois = null;
try {
fis = new FileInputStream(new File(fileName));
ois = new ObjectInputStream(fis);
BigInteger modulus = (BigInteger) ois.readObject();
BigInteger exponent = (BigInteger) ois.readObject();
RSAPrivateKeySpec rsaPrivateKeySpec = new RSAPrivateKeySpec(modulus, exponent);
KeyFactory fact = KeyFactory.getInstance("RSA");
PrivateKey privateKey = fact.generatePrivate(rsaPrivateKeySpec);
return privateKey;
} catch (Exception e) {
e.printStackTrace();
} finally {
if (ois != null) {
ois.close();
if (fis != null) {
fis.close();
}
}
}
return null;
}
public static void writeStringkey(String fileName, String data) {
try {
FileWriter out = new FileWriter(new File(fileName));
out.write(data);
out.close();
} catch (IOException e) {
}
}
public static String readStringKey(String fileName) {
BufferedReader reader = null;
StringBuffer fileData = null;
try {
fileData = new StringBuffer(2048);
reader = new BufferedReader(new FileReader(fileName));
char[] buf = new char[1024];
int numRead = 0;
while ((numRead = reader.read(buf)) != -1) {
String readData = String.valueOf(buf, 0, numRead);
fileData.append(readData);
buf = new char[1024];
}
reader.close();
} catch (Exception e) {
} finally {
if (reader != null) {
reader = null;
}
}
return fileData.toString();
}
}
Where is mistaken point.? Decryption part is give that error.
Whole class uploaded here
LINK TO SOURCE CODE
错点在哪里。？解密部分给出了那个错误。
全班在这里上传
链接到源代码
-Thanks
-谢谢
回答by Maarten Bodewes
In principle a ciphertext should be indistinguishable from random. That said, ciphers do place constraints on the domain (size and possible values). In the case of RSA PKCS#1 - which is the default mode for "RSA" within the Oracle provider - the output must be precisely the key size (in bytes). Furthermore, the value must be smaller than the modulus.
原则上，密文应该与随机无法区分。也就是说，密码确实对域（大小和可能的值）施加了限制。在 RSA PKCS#1 的情况下 - 这是 Oracle 提供程序中“RSA”的默认模式 - 输出必须恰好是密钥大小（以字节为单位）。此外，该值必须小于模数。
Now assume that you've just shown us a demo value (because the exception doesn't match the input) and the size of the ciphertext is correct. In that case you would get an unpadding exception when either:
现在假设您刚刚向我们展示了一个演示值（因为异常与输入不匹配）并且密文的大小是正确的。在这种情况下，您将在以下任一情况下获得取消填充异常：
- the private key doesn't match the public key used;
- the wrong padding mode (e.g. OAEP) was used to create the ciphertext;
- the ciphertext was altered (e.g. due to an invalid conversion to a string).
- 私钥与使用的公钥不匹配；
- 使用错误的填充模式（例如 OAEP）来创建密文；
- 密文被更改（例如，由于向字符串的无效转换）。
You would have to try until you find the culprit, without the required information we cannot test this for you.
您必须尝试直到找到罪魁祸首，如果没有所需的信息，我们将无法为您测试。
