golang实现pyffx

package main

import (
    "bytes"
    "crypto/aes"
    "crypto/cipher"
    "crypto/rand"
    "crypto/sha1"
    "fmt"
    "strconv"
)

const (
    blocksize = 8
)

var (
    seed = []byte("0123456789abcdef")
)

func main() {
    key := []byte("this is a secret key")
    text := []byte("hello world")

    // 初始化
    parameters, err := cipherSuite(key)
    if err != nil {
        panic(err)
    }

    // 加密
    ciphertext := encrypt(text, parameters)
    fmt.Println("ciphertext:", ciphertext)

    // 解密
    plaintext := decrypt(ciphertext, parameters)
    fmt.Println("plaintext:", plaintext)
}

func cipherSuite(key []byte) (cipher.Block, error) {
    // 计算密钥的散列值
    keyDigest := sha1.Sum(key)

    // 生成参数
    params := make([]byte, 20)
    copy(params, keyDigest[:])

    // 生成加密器
    block, err := aes.NewCipher(params)
    if err != nil {
        return nil, err
    }

    return block, nil
}

func encrypt(plaintext []byte, parameters cipher.Block) []byte {
    // 对明文进行补位操作
    padLength := blocksize - len(plaintext)%blocksize
    padded := append(plaintext, bytes.Repeat([]byte{byte(padLength)}, padLength)...)

    // 对补位后的明文进行加密
    ciphertext := make([]byte, len(padded))
    for i := 0; i < len(padded); i += blocksize {
        parameters.Encrypt(ciphertext[i:i+blocksize], padded[i:i+blocksize])
    }

    // 对密文进行编码
    encoded := make([]byte, hex.EncodedLen(len(ciphertext)))
    hex.Encode(encoded, ciphertext)

    return encoded
}

func decrypt(encoded []byte, parameters cipher.Block) []byte {
    // 对密文进行解码
    decoded := make([]byte, hex.DecodedLen(len(encoded)))
    _, err := hex.Decode(decoded, encoded)
    if err != nil {
        panic(err)
    }

    // 对解码后的密文进行解密
    padded := make([]byte, len(decoded))
    for i := 0; i < len(decoded); i += blocksize {
        parameters.Decrypt(padded[i:i+blocksize], decoded[i:i+blocksize])
    }

    // 对解密后的明文进行去位操作
    padLength := int(padded[len(padded)-1])
    plaintext := padded[:len(padded)-padLength]

    return plaintext
}

func randInt(seed []byte, i int) int {
    r, _ := strconv.Atoi(randString(seed, i))
    return r
}

func randString(seed []byte, i int) string {
    var pt string
    for x := range seed {
        pt += strconv.Itoa(int(seed[x]))
    }
    res := ""
    for x := range pt {
        var n int
        if x+i >= len(pt) {
            n = int(pt[x])
        } else {
            n = int(pt[x+i])
        }
        res += strconv.Itoa(n%10 + randInt(seed, i+1))
    }
    return res
}