如何在Java中使用AES算法解密加密字符串?
我不能用Java解密AES加密的文本。这是我的密码:如何在Java中使用AES算法解密加密字符串?,java,string,encryption,aes,Java,String,Encryption,Aes,我不能用Java解密AES加密的文本。这是我的密码: import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.SecretKey; import javax.xml.bind.DatatypeConverter; public class aesencrypt { public static void main(String[] args) throws Exception {
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.xml.bind.DatatypeConverter;
public class aesencrypt {
public static void main(String[] args) throws Exception {
String plainText = "Hello World";
System.out.println("Original Text:" + plainText);
SecretKey secKey = getSecretEncryptionKey();
System.out.println("AES Key (Hex Form):"+bytesToHex(secKey.getEncoded()));
String encryptedText = bytesToHex(encryptText(plainText, secKey));
System.out.println("Encrypted Text (Hex Form):"+encryptedText);
String decryptedText = decryptText(encryptedText, secKey);
System.out.println("Descrypted Text:"+decryptedText);
}
public static SecretKey getSecretEncryptionKey() throws Exception{
KeyGenerator generator = KeyGenerator.getInstance("AES");
generator.init(128); // The AES key size in number of bits
SecretKey secKey = generator.generateKey();
return secKey;
}
public static byte[] encryptText(String plainText,SecretKey secKey) throws Exception{
// AES defaults to AES/ECB/PKCS5Padding in Java 7
Cipher aesCipher = Cipher.getInstance("AES");
aesCipher.init(Cipher.ENCRYPT_MODE, secKey);
byte[] byteCipherText = aesCipher.doFinal(plainText.getBytes());
return byteCipherText;
}
public static String decryptText(String encrypted, SecretKey secKey) throws Exception {
// AES defaults to AES/ECB/PKCS5Padding in Java 7
Cipher aesCipher = Cipher.getInstance("AES");
aesCipher.init(Cipher.DECRYPT_MODE, secKey);
byte[] bytePlainText = aesCipher.doFinal(encrypted.getBytes());
return new String(bytePlainText);
}
private static String bytesToHex(byte[] hash) {
return DatatypeConverter.printHexBinary(hash);
}
}
运行此操作时,以下输出中出现错误:
Original Text:Hello World
AES Key (Hex Form):4690FFCDC7B5E8B128F5BF45F0920527
Encrypted Text (Hex Form):7C092F40D592F9DF83F3D4E976612928
Exception in thread "main" javax.crypto.BadPaddingException: Given final block not properly padded
at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:989)
at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:845)
at com.sun.crypto.provider.AESCipher.engineDoFinal(AESCipher.java:446)
at javax.crypto.Cipher.doFinal(Cipher.java:2165)
at aesencrypt.decryptText(aesencrypt.java:38)
at aesencrypt.main(aesencrypt.java:15)
我已经搜索了堆栈溢出和搜索引擎,但实际上找不到解决方案
问题解决
更新:问题已解决,感谢您提供的解决方案
修订守则:
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.xml.bind.DatatypeConverter;
public class aesencrypt {
public static void main(String[] args) throws Exception {
String plainText = "Hello World";
System.out.println("Original Text:" + plainText);
SecretKey secKey = getSecretEncryptionKey();
System.out.println("AES Key (Hex Form):"+bytesToHex(secKey.getEncoded()));
String encryptedText = bytesToHex(encryptText(plainText, secKey));
System.out.println("Encrypted Text (Hex Form):"+encryptedText);
String decryptedText = decryptText(encryptedText, secKey);
System.out.println("Decrypted Text:"+decryptedText);
}
public static SecretKey getSecretEncryptionKey() throws Exception{
KeyGenerator generator = KeyGenerator.getInstance("AES");
generator.init(128);
SecretKey secKey = generator.generateKey();
return secKey;
}
public static byte[] encryptText(String plainText,SecretKey secKey) throws Exception{
Cipher aesCipher = Cipher.getInstance("AES");
aesCipher.init(Cipher.ENCRYPT_MODE, secKey);
byte[] byteCipherText = aesCipher.doFinal(plainText.getBytes());
return byteCipherText;
}
public static String decryptText(String encrypted, SecretKey secKey) throws Exception {
Cipher aesCipher = Cipher.getInstance("AES");
aesCipher.init(Cipher.DECRYPT_MODE, secKey);
byte[] bytePlainText = aesCipher.doFinal(hexToByte(encrypted));
return new String(bytePlainText);
}
private static String bytesToHex(byte[] hash) {
return DatatypeConverter.printHexBinary(hash);
}
private static byte[] hexToByte(String txt) {
return DatatypeConverter.parseHexBinary(txt);
}
}
以下是输出:
Original Text:Hello World
AES Key (Hex Form):84526F32BEDDBEA5BFBCDE241AD9BBA2
Encrypted Text (Hex Form):25378032E5F52575B7CEF311D45F00BD
Decrypted Text:Hello World
看看你在做什么:
String encryptedText = bytesToHex(encryptText(plainText, secKey));
String decryptedText = decryptText(encryptedText, secKey);
在这里,您可以将纯文本转换为字节(使用有损的、依赖于平台的getBytes()
,顺便说一句,您应该使用UTF8)
然后加密这些字节并得到一个字节数组。然后将这个字节数组编码为十六进制
因此,反向操作是:从十六进制解码为字节,然后解密这些字节,然后从描述的字节构造一个字符串
但你现在做的是:
String encryptedText = bytesToHex(encryptText(plainText, secKey));
String decryptedText = decryptText(encryptedText, secKey);
其中decryptText()执行以下操作:
所以,你永远不会使用十六进制解码。如果一边使用
bytesToHex()
,另一边则需要使用hexToBytes()
。该异常意味着用于解密的密钥被错误使用,必须使用它。:)@JerylCook您可以清楚地看到,解密中使用的密钥变量secKey与加密中使用的完全相同。那么,密钥怎么可能是错误的呢?请看下面的答案。这与解码密钥的方式不同…这就是为什么会出现填充错误。问题已经解决,但我仍然想知道如何将十六进制密钥转换为原始密钥。例如://它以十六进制形式存储密钥
字符串hexSecKey=bytesToHex(getsecretincryptionkey().getEncoded())
//如何从十六进制密钥获取原始密钥?
SecretKey secKey=???
从这里得到答案: