密码

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package main
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import ("fmt")
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func XORCipher(data []byte, key string) []byte {
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  keyBytes := []byte(key)
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  keyLen := len(keyBytes)
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  result := make([]byte, len(data))
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  for i := range data {
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    keyByte := keyBytes[i%keyLen]
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    intermediate := data[i] ^ keyByte
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    shifted := (intermediate << 3) | (intermediate >> 5)
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    result[i] = shifted
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  }
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  return result
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}
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func main() {
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  flag := "flag{*************}"
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  key := "s3cr3tK3y"
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  dataToEncrypt := []byte(flag)
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  encryptedData := XORCipher(dataToEncrypt, key)
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  fmt.Printf("Ciphertext: ")
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  for _, b := range encryptedData {
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    fmt.Printf("%02x", b)
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  }
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  // Output: a8fa10a842b1fb8b0061a29a12185998185992901278
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}

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package main
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import ("fmt")
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// 解密函数，逆运算
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func Decrypt(cipher []byte, key string) []byte {
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  keyBytes := []byte(key)
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  keyLen := len(keyBytes)
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  result := make([]byte, len(cipher))
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  for i := range cipher {
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    // 逆：循环右移3位，还原intermediate
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    intermediate := (cipher[i] >> 3) | (cipher[i] << 5)
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    keyByte := keyBytes[i%keyLen]
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    result[i] = intermediate ^ keyByte
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  }
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  return result
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}
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func main() {
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  // 题目给出的密文hex
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  hexStr := "a8fa10a842b1fb8b0061a29a12185998185992901278"
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  key := "s3cr3tK3y"
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  // 把hex转byte数组
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  var cipher []byte
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  for i := 0; i < len(hexStr); i += 2 {
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    var b byte
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    fmt.Sscanf(hexStr[i:i+2], "%02x", &b)
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    cipher = append(cipher, b)
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  }
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  plain := Decrypt(cipher, key)
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  fmt.Println("Decrypted flag:", string(plain))
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}

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import requests
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import random
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import re
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url = "http://127.0.0.1:49598"
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for _ in range(1000):
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    ip = f"{random.randint(1,255)}.{random.randint(1,255)}.{random.randint(1,255)}.{random.randint(1,255)}"
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    headers = {
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        "X-Forwarded-For": ip
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    }
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    res = requests.get(url, headers=headers)
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    html = res.text
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    # 修改正则：<br>后面抓取所有字符，直到换行
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    match = re.search(r"<br>(.+)", html)
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    if match:
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        content = match.group(1).strip()
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        print(f"IP:{ip:15} | 内容: {content}")
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        if "flag{" in content:
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            print("\n✅✅✅找到FLAG！！", content)
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            break