我正在做一个项目，我需要使用AES加密字符串。 该程序需要能够接受一个String并以十六进制形式输出一个加密的字符串以及一个密钥，或者使用用户指定的密钥和字符串来输出未加密的文本（也就是说，该程序必须能够在不同的实例中完成这两项操作，即我应该能够在计算机上输入“ 1234”并取出“加密文本：asdf密钥：ghjk”；我的朋友应该能够输入“加密文本：asdf KEy ：ghjk”，然后退出“ 1234”）
这是我到目前为止的内容：
package betterencryption;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.util.Scanner;
public class BetterEncryption {
public static String asHex (byte buf[]) { //asHex works just fine, it's the main that's
//giving me trouble
StringBuffer strbuf = new StringBuffer(buf.length * 2);
int i;
for (i = 0; i < buf.length; i++) {
if (((int) buf[i] & 0xff) < 0x10)
strbuf.append("0");
strbuf.append(Long.toString((int) buf[i] & 0xff, 16));
}
return strbuf.toString();
}
public static void main(String[] args) throws Exception {
Scanner sc = new Scanner(System.in);
KeyGenerator kgen = KeyGenerator.getInstance("AES");kgen.init(128);
SecretKey skey = kgen.generateKey();
byte[] bytes = skey.getEncoded();
SecretKeySpec skeySpec = new SecretKeySpec(bytes, "AES");
Cipher cipher = Cipher.getInstance("AES");
System.out.print("Do you want to encrypt or unencrypt?\n");/*This is a weird way of doing it,*/
String choice = sc.next(); char cc = choice.charAt(2); /*I know, but this part checks to see if*/
if(cc=='c'){ /*the program is to encrypt or unencrypt*/
System.out.print("Enter a string to encrypt: "); /* a string. The 'encrypt' function works.*/
String message = sc.next();
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] encrypted = cipher.doFinal((args.length == 0 ? message : args[0]).getBytes());
System.out.println("Encrypted string: " + asHex(encrypted)+"\nKey: "+asHex(bytes));
//^This^ section actually works! The code outputs an encrypted string and everything.
//It's beautiful
//Unfortunately getting that string back into readable text has been problematic
//Which is where you guys come in!
//Hopefully
}
if(true){
System.out.print("\nEnter the encrypted string: "); String encryptedString = sc.next();
System.out.print("\nEnter the key: "); String keyString = sc.next();
int len = encryptedString.length(); /*this section converts the user-input string*/
byte[] encrypted = new byte[len / 2]; /*into an array of bytes*/
for (int i = 0; i < len; i += 2) { /*I'm not sure if it works, though*/
encrypted[i / 2] = (byte) ((Character.digit(encryptedString.charAt(i), 16) << 4)+
Character.digit(encryptedString.charAt(i+1), 16));
cipher.init(Cipher.DECRYPT_MODE, skeySpec); /*as you can see, I haven't even begun to implement*/
byte[] original = cipher.doFinal(encrypted);/*a way to allow the user-input key to be used.*/
String originalString = new String(original);
System.out.println("\nOriginal string: "+originalString); //I'm really quite stuck.
//can you guys help?
}
}
}
}
好吧，希望有人能帮助我。
编辑：
我最大的问题是将String encryptionString转换为sKeySpec，并弄清楚如何防止“ unencrypt”功能给用户一个错误，指出他们输入的字符串未正确填充。 我知道这是不对的，因为我尝试了对String进行加密，然后将其加密形式粘贴到uncryptor中只是为了得到一个错误。 如果我消除了所有的“ if”条件，并且只对它加密了一个字符串，然后在同一实例中对其进行了解密，则该程序运行良好。 我认为这是由于保留了keyGen的随机密钥