文字加密

复制import string

# 凯撒密码：移位 3
plain = "hello, world"
shift = 3
lower = string.ascii_lowercase
cipher = ''.join(
    lower[(lower.index(c) + shift) % 26] if c in lower else c
    for c in plain
)
print(cipher)  # khoor, zruog

# 倒序
reversed_text = plain[::-1]
print(reversed_text)  # dlrow ,olleh

# 简单替换：a→x, b→y, c→z ...
table = str.maketrans(string.ascii_lowercase, string.ascii_lowercase[23:] + string.ascii_lowercase[:3])
substituted = plain.translate(table)
print(substituted)  # ebii1, xli2

复制package main

import (
	"fmt"
	"strings"
	"unicode"
)

// 凯撒移位（仅小写字母）
func caesar(s string, shift int) string {
	var b strings.Builder
	for _, r := range s {
		if unicode.IsLower(r) {
			r = rune((int(r-'a')+shift)%26 + 'a')
		}
		b.WriteRune(r)
	}
	return b.String()
}

func main() {
	plain := "hello, world"
	fmt.Println(caesar(plain, 3)) // khoor, zruog

	// 倒序
	runes := []rune(plain)
	for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
		runes[i], runes[j] = runes[j], runes[i]
	}
	fmt.Println(string(runes)) // dlrow ,olleh
}

复制// 凯撒密码（仅小写字母）
function caesar(str, shift) {
  return str.replace(/[a-z]/g, ch =>
    String.fromCharCode(((ch.charCodeAt(0) - 97 + shift) % 26) + 97)
  );
}

const plain = "hello, world";
console.log(caesar(plain, 3)); // khoor, zruog

// 倒序
console.log([...plain].reverse().join('')); // dlrow ,olleh

// Vigenere 加密（仅小写字母）
function vigenereEncrypt(plain, key) {
  let result = '';
  for (let i = 0, j = 0; i < plain.length; i++) {
    const c = plain[i];
    if (/[a-z]/.test(c)) {
      const shift = key[j % key.length].charCodeAt(0) - 97;
      result += String.fromCharCode((c.charCodeAt(0) - 97 + shift) % 26 + 97);
      j++;
    } else {
      result += c;
    }
  }
  return result;
}
console.log(vigenereEncrypt(plain, 'key')); // riovu, yqznv