com.dahuatech.hutool.crypto.symmetric.Vigenere Maven / Gradle / Ivy

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Dahua ICC Open API SDK for Java

There is a newer version: 1.0.13.7

package com.dahuatech.hutool.crypto.symmetric;

/**
 * 维吉尼亚密码实现。

 * 人们在恺撒移位密码的基础上扩展出多表密码，称为维吉尼亚密码。

 * 算法实现来自：https://github.com/zhaorenjie110/SymmetricEncryptionAndDecryption
 *
 * @author looly,zhaorenjie110
 * @since 4.4.1
 */
public class Vigenere {

  /**
   * 加密
   *
   * @param data 数据
   * @param cipherKey 密钥
   * @return 密文
   */
  public static String encrypt(CharSequence data, CharSequence cipherKey) {
    final int dataLen = data.length();
    final int cipherKeyLen = cipherKey.length();

    final char[] cipherArray = new char[dataLen];
    for (int i = 0; i < dataLen / cipherKeyLen + 1; i++) {
      for (int t = 0; t < cipherKeyLen; t++) {
        if (t + i * cipherKeyLen < dataLen) {
          final char dataChar = data.charAt(t + i * cipherKeyLen);
          final char cipherKeyChar = cipherKey.charAt(t);
          cipherArray[t + i * cipherKeyLen] = (char) ((dataChar + cipherKeyChar - 64) % 95 + 32);
        }
      }
    }

    return String.valueOf(cipherArray);
  }

  /**
   * 解密
   *
   * @param data 密文
   * @param cipherKey 密钥
   * @return 明文
   */
  public static String decrypt(CharSequence data, CharSequence cipherKey) {
    final int dataLen = data.length();
    final int cipherKeyLen = cipherKey.length();

    final char[] clearArray = new char[dataLen];
    for (int i = 0; i < dataLen; i++) {
      for (int t = 0; t < cipherKeyLen; t++) {
        if (t + i * cipherKeyLen < dataLen) {
          final char dataChar = data.charAt(t + i * cipherKeyLen);
          final char cipherKeyChar = cipherKey.charAt(t);
          if (dataChar - cipherKeyChar >= 0) {
            clearArray[t + i * cipherKeyLen] = (char) ((dataChar - cipherKeyChar) % 95 + 32);
          } else {
            clearArray[t + i * cipherKeyLen] = (char) ((dataChar - cipherKeyChar + 95) % 95 + 32);
          }
        }
      }
    }
    return String.valueOf(clearArray);
  }
}