了解主流加密方式：离散、对称与非对称加密算法

package main

import (
  "crypto/aes"
  "crypto/cipher"
  "crypto/rand"
  "crypto/rsa"
  "crypto/sha256"
  "encoding/hex"
  "fmt"
  "io"
)

// 离散加密 - 哈希函数示例
func hashEncryption(data []byte) string {
  hash := sha256.Sum256(data)
  return hex.EncodeToString(hash[:])
}

// 对称加密 - AES示例
func symmetricEncryption(plaintext []byte, key []byte) ([]byte, error) {
  block, err := aes.NewCipher(key)
  if err != nil {
    return nil, err
  }

  // 使用随机IV向量
  ciphertext := make([]byte, aes.BlockSize+len(plaintext))
  iv := ciphertext[:aes.BlockSize]
  if _, err := io.ReadFull(rand.Reader, iv); err != nil {
    return nil, err
  }

  // 使用CBC模式进行加密
  mode := cipher.NewCBCEncrypter(block, iv)
  mode.CryptBlocks(ciphertext[aes.BlockSize:], plaintext)

  return ciphertext, nil
}

// 非对称加密 - RSA示例
func asymmetricEncryption(plaintext []byte, publicKey *rsa.PublicKey) ([]byte, error) {
  ciphertext, err := rsa.EncryptPKCS1v15(rand.Reader, publicKey, plaintext)
  if err != nil {
    return nil, err
  }
  return ciphertext, nil
}

func main() {
  // 离散加密示例 - 哈希函数
  hashedValue := hashEncryption([]byte("Hello, World!"))
  fmt.Println("Hashed value:", hashedValue)

  // 对称加密示例 - AES
  key := []byte("1234567890123456") // 16字节密钥
  plaintext := []byte("Hello, World!")

  ciphertext, err := symmetricEncryption(plaintext, key)
  if err != nil {
    fmt.Println("Error during symmetric encryption:", err)
    return
  }

  fmt.Println("Ciphertext:", ciphertext)

  // 非对称加密示例 - RSA
  privateKey, err := rsa.GenerateKey(rand.Reader, 2048)
  if err != nil {
    fmt.Println("Error generating RSA key pair:", err)
    return
  }

  publicKey := &privateKey.PublicKey
  ciphertext, err = asymmetricEncryption(plaintext, publicKey)
  if err != nil {
    fmt.Println("Error during asymmetric encryption:", err)
    return
  }

  fmt.Println("Ciphertext:", ciphertext)
}