非法块大小异常当使用填充密码解密时，输入长度必须是16的倍数 [英] Illegal Block Size Exception Input length must be multiple of 16 when decrypting with padded cipher
问题描述
在我的应用程序中，我使用secretKey加密和解密数据。为此，我使用AES算法。但是我在解密时遇到异常，使用密钥在三个已经加密的值中有一个值。
In my application I am encrypting and decrypting data using secretKey. For that I am using AES algorithm. But I am getting exception in decrypt, one value out of three already encrypted values using secret key.
例外情况是：
Illegal Block Size Exception Input length must be multiple of 16 when decrypting with padded cipher.
以下是我的代码：
encyrpt值的函数
public static String symmetricEncrypt(String text, String secretKey) {
BASE64Decoder decoder = new BASE64Decoder();
byte[] raw;
String encryptedString;
SecretKeySpec skeySpec;
BASE64Encoder bASE64Encoder = new BASE64Encoder();
byte[] encryptText = text.getBytes();
Cipher cipher;
try {
raw = decoder.decodeBuffer(secretKey);
skeySpec = new SecretKeySpec(raw, "AES");
cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
encryptedString = bASE64Encoder.encode(cipher.doFinal(encryptText));
}
catch (Exception e) {
e.printStackTrace();
return "Error";
}
return encryptedString;
}
解密价值的功能
public static String symmetricDecrypt(String text, String secretKey) {
BASE64Decoder decoder = new BASE64Decoder();
BASE64Decoder base64Decoder = new BASE64Decoder();
Cipher cipher;
String encryptedString;
byte[] encryptText = null;
byte[] raw;
SecretKeySpec skeySpec;
try {
raw = decoder.decodeBuffer(secretKey);
skeySpec = new SecretKeySpec(raw, "AES");
encryptText = base64Decoder.decodeBuffer(text);
cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
encryptedString = new String(cipher.doFinal(encryptText));
} catch (Exception e) {
e.printStackTrace();
return "Error";
}
return encryptedString;
}
以下是我正在加密和解密的值
Following are the values that I am encrypting and decrypting
String secretKey = "XMzDdG4D03CKm2IxIWQw7g==";
String value1= "ABCD";
String enctypedValue1= "3uweh4pzoVyH1uODQmVNJA==";
String enctypedValue2= "37PTC20w4DMZYjG3f+GWepSvAbEJUccMXwS/lXilLav1qM/PrCTdontw5/82OdC1zzyhDEsFVRGo rV6gXAQcm+Zai15hliiUQ8l8KRMtUl4=";
String value4= "20000";
/** Ecnryption and decryption of value1 **/
String encryptedValue1= symmetricEncrypt(value1, secretKey);
String decryptedValue1 = symmetricDecrypt(encryptedValue1, secretKey);
/** Decryption of enctypedValue1 **/
String decryptedValue2 = symmetricDecrypt(enctypedValue1, secretKey);
System.out.println(decryptedValue2);
/** Decryption of enctypedValue2 (Not decrypted)**/
String decryptedValue3 = symmetricDecrypt(enctypedValue2, secretKey);
System.out.println(decryptedValue3);
/** Ecnryption and decryption of value4 **/
String encryptedValue4= symmetricEncrypt(value4, secretKey);
String decryptedValue4 = symmetricDecrypt(encryptedValue4, secretKey);
在测试函数中，我编写了以下三个测试用例。
In the test function, I have written the following three test cases.
- 使用密钥加密和解密的新值（value1）。
- 两个示例加密值（enctypedValue1，enctypedValue2）正在使用相同的密钥解密。 encryptedValue2在使用相同的密钥解密时出现问题。
- 使用密钥加密和解密的新值（value4）。
在解密encryptedValue2时，我收到以下异常：
On decrypting encryptedValue2 I am getting the following exception:
Illegal Block Size Exception Input length must be multiple of 16 when decrypting with padded cipher
以下是我迄今为止所得到的。
Following is what I have derived till now.
-
有问题的值在解码时似乎有问题，它返回81长度数组，无法解密？
The problematic value seems to have a problem while decoding it, it returns 81 length array which is unable to get decrypted?
如果发生这个问题，它应该发生在所有值上。
If this problem was to happen it should have happened to all the values.
是这是一个特定于值的问题，或者它与填充有关，或者它可以在不同的浏览器上有不同的行为，不同的操作系统？
Is this a value specific problem or it is something related to padding or it can have a different behavior on different browser, different os?
推荐答案
我能够毫无问题地运行代码。但是，我使用Apache的Base64进行编码/解码...也许你的Base64有bug。如果你自己写的，很有可能你错过了一些案例。对于真正的生产代码，使用经过严格测试的库，例如Apache。
I was able to run the code without any problem. However, I used Apache's Base64 for encoding/decoding...maybe your Base64 has bugs. If you wrote it yourself, there is a big chance that you missed some cases. For real production code, use heavily tested libraries such as Apache's.
你可以在这里找到我用于Base64的库： http://commons.apache.org/proper/commons-codec/download_codec.cgi
You can find the library that I used for Base64 here: http://commons.apache.org/proper/commons-codec/download_codec.cgi
以下是完整的工作代码：
Here is the full working code:
package security.symmatric;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Base64;
public class AES {
public static String symmetricEncrypt(String text, String secretKey) {
byte[] raw;
String encryptedString;
SecretKeySpec skeySpec;
byte[] encryptText = text.getBytes();
Cipher cipher;
try {
raw = Base64.decodeBase64(secretKey);
skeySpec = new SecretKeySpec(raw, "AES");
cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
encryptedString = Base64.encodeBase64String(cipher.doFinal(encryptText));
}
catch (Exception e) {
e.printStackTrace();
return "Error";
}
return encryptedString;
}
public static String symmetricDecrypt(String text, String secretKey) {
Cipher cipher;
String encryptedString;
byte[] encryptText = null;
byte[] raw;
SecretKeySpec skeySpec;
try {
raw = Base64.decodeBase64(secretKey);
skeySpec = new SecretKeySpec(raw, "AES");
encryptText = Base64.decodeBase64(text);
cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
encryptedString = new String(cipher.doFinal(encryptText));
} catch (Exception e) {
e.printStackTrace();
return "Error";
}
return encryptedString;
}
public static void main(String[] args) {
String secretKey = "XMzDdG4D03CKm2IxIWQw7g==";
String value1= "ABCD";
String enctypedValue1= "3uweh4pzoVyH1uODQmVNJA==";
String enctypedValue2= "37PTC20w4DMZYjG3f+GWepSvAbEJUccMXwS/lXilLav1qM/PrCTdontw5/82OdC1zzyhDEsFVRGo rV6gXAQcm+Zai15hliiUQ8l8KRMtUl4=";
String value4= "20000";
/** Ecnryption and decryption of value1 **/
String encryptedValue1= symmetricEncrypt(value1, secretKey);
String decryptedValue1 = symmetricDecrypt(encryptedValue1, secretKey);
System.out.println(decryptedValue1);
/** Decryption of enctypedValue1 **/
String decryptedValue2 = symmetricDecrypt(enctypedValue1, secretKey);
System.out.println(decryptedValue2);
/** Decryption of enctypedValue2 **/
String decryptedValue3 = symmetricDecrypt(enctypedValue2, secretKey);
System.out.println(decryptedValue3);
/** Ecnryption and decryption of value4 **/
String encryptedValue4= symmetricEncrypt(value4, secretKey);
String decryptedValue4 = symmetricDecrypt(encryptedValue4, secretKey);
System.out.println(decryptedValue4);
}
}
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