com.siashan.toolkit.crypt.symmetric.Vigenere Maven / Gradle / Ivy
package com.siashan.toolkit.crypt.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
*
* 从开源项目 Hutool 复制而来
* @author siashan
* @since 1.0.7
*/
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);
}
}