写一个BreakCaesarCipher程序

Question

所以我有一个编程问题。我希望能够创建一个执行以下操作的breakCaesarCipher类：

1）拆分加密的消息

2）确定两个解密密钥

3）使用这些键创建CaesarCipherTwo实例。

4）调用解密方法。

我不知道从哪里开始。我对如何拆分加密邮件感到困惑。在上一课中，我们这样做了：

import edu.duke.*;

public class CaesarBreaker2 {
    public int[] countOccurrencesOfLetters(String message) {
        //snippet from lecture
        String alph = "abcdefghijklmnopqrstuvwxyz";
        int[] counts = new int[26];
        for (int k=0; k < message.length(); k++) {
            char ch = Character.toLowerCase(message.charAt(k));
            int dex = alph.indexOf(ch);
            if (dex != -1) {
                counts[dex] += 1;
            }
        }
        return counts;
    }
    public int maxIndex(int[] values) {
        int maxDex = 0;
        for (int k=0; k < values.length; k++) {
            if (values[k] > values[maxDex]) {
                maxDex = k;
            }
        }
        return maxDex;
    }
    public String decrypt(String encrypted) {
        CaesarCipher cc = new CaesarCipher();
        int[] freqs = countOccurrencesOfLetters(encrypted);
        int maxDex = maxIndex(freqs);
        int dkey = maxDex - 4;
        if (maxDex < 4) {
            dkey = 26 - (4-maxDex);
        }
        return cc.encrypt(encrypted,26-dkey);
    }
    public String halfOfString(String message, int start) {
        StringBuilder halfString = new StringBuilder();
        for (int index=start;index < message.length();index += 2) {
            halfString.append(message.charAt(index));
        }
        return halfString.toString();
    }
    public int getKey(String s) {
        int[] letterFreqs = countOccurrencesOfLetters(s);
        int maxDex = maxIndex(letterFreqs);
        int dkey = maxDex - 4;
        if (maxDex < 4) {
            dkey = 26 - (4-maxDex);
        }
        return 26-dkey;
    }
    public String decryptTwoKeys(String encrypted) {
        String firstHalfEncrypted = halfOfString(encrypted,0);
        String secondHalfEncrypted = halfOfString(encrypted,1);
        int firstHalfKey = getKey(firstHalfEncrypted);
        int secondHalfKey = getKey(secondHalfEncrypted);
        CaesarCipherTwo ccT = new CaesarCipherTwo();

        System.out.println("First key:\t" + firstHalfKey + "\nSecond key:\t"
                            + secondHalfKey);

        return ccT.encryptTwoKeys(encrypted,firstHalfKey,secondHalfKey);
    }
    public void testDecrypt() {
        FileResource fileResource = new FileResource();
        String encrypted = fileResource.asString();
        System.out.println("Encrypted message:\n" + encrypted);
        System.out.println("\nDecrypted message:\n" + decryptTwoKeys(encrypted));

        String encrypted2 = "Aal uttx hm aal Qtct Fhljha pl Wbdl. Pvxvxlx!";
        System.out.println("Encrypted message:\n" + encrypted2);
        System.out.println("\nDecrypted message:\n" + decryptTwoKeys(encrypted2));
    }
}

但我不明白如何转换此代码，因此它将在这个名为TestCaesarCipherTwo的新类中工作。以下是TestCaesarCipherTwo的代码：

import edu.duke.*;


public class TestCaesarCipherTwo {
   public int[] countOccurrencesOfLetters(String message) {
        //snippet from lecture
        String alph = "abcdefghijklmnopqrstuvwxyz";
        int[] counts = new int[26];
        for (int k=0; k < message.length(); k++) {
            char ch = Character.toLowerCase(message.charAt(k));
            int dex = alph.indexOf(ch);
            if (dex != -1) {
                counts[dex] += 1;
            }
        }
        return counts;
    }
    public int maxIndex(int[] values) {
        int maxDex = 0;
        for (int k=0; k < values.length; k++) {
            if (values[k] > values[maxDex]) {
                maxDex = k;
            }
        }
        return maxDex;
   }

   public String halfOfString(String message, int start) {
        StringBuilder halfString = new StringBuilder();
        for (int index=start;index < message.length();index += 2) {
            halfString.append(message.charAt(index));
        }
        return halfString.toString();

   }
      public void simpleTests() {
        FileResource fileResource = new FileResource();
        String fileAsString = fileResource.asString();
        CaesarCipherTwoKeys cctk = new CaesarCipherTwoKeys(17, 3);
        String encrypted = cctk.encrypt(fileAsString);
        System.out.println("Encrypted string:\n"+encrypted);
        String decrypted = cctk.decrypt(encrypted);
        System.out.println("Decrypted string:\n"+decrypted);

        String blindDecrypted = breakCaesarCipher(encrypted);
        System.out.println("Decrypted string using breakCaesarCipher():\n"+blindDecrypted);
   }
    public String breakCaesarCipher(String input) {
        int[] freqs = countOccurrencesOfLetters(input);
        int freqDex = maxIndex(freqs);
        int dkey = freqDex - 4;
        if (freqDex < 4) {
            dkey = 26 - (4-freqDex);
        }
        CaesarCipherTwoKeys cctk = new CaesarCipherTwoKeys(dkey);
        return cctk.decrypt(input);
   }
}

警告：此行上也有构造函数错误CaesarCipherTwoKeys cctk = new CaesarCipherTwoKeys（dkey）;在类CaesarCipherTwoKeys中声明CaesarCipherTwoKeys不能应用于给定类型; required int，int;找到了......

任何人都可以告诉我如何更改我的代码，以便我的breakCaesarCipher方法拆分加密的消息，确定用于加密消息的两个解密密钥，用这两个密钥创建CaesarCipherTwo的实例，并调用解密方法？欢迎任何建议。如果您想了解更多有关此问题性质的详细信息，请与我们联系。