88 lines
2.1 KiB
Go
88 lines
2.1 KiB
Go
package cryptoaes
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import (
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"bytes"
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"encoding/base64"
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"fmt"
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)
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// Encrypt 加密算法
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func Encrypt(key, plaintext string) (string, error) {
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keyByte := []byte(key)
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plaintextByte := []byte(plaintext)
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// 创建一个 AES 块
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block, err := aes.NewCipher(keyByte)
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if err != nil {
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return "", err
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}
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// 对明文进行填充
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padding := aes.BlockSize - (len(plaintext) % aes.BlockSize)
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padText := append(plaintextByte, bytes.Repeat([]byte{byte(padding)}, padding)...)
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ciphertext := make([]byte, aes.BlockSize+len(padText))
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// 生成随机的 IV
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iv := ciphertext[:aes.BlockSize]
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if _, err := rand.Read(iv); err != nil {
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return "", err
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}
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// 解密数据
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mode := cipher.NewCBCEncrypter(block, iv)
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mode.CryptBlocks(ciphertext[aes.BlockSize:], padText)
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return base64.StdEncoding.EncodeToString(ciphertext), nil
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}
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// Decrypt 解密算法
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func Decrypt(key, ciphertext string) (string, error) {
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ciphertextByte, err := base64.StdEncoding.DecodeString(ciphertext)
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if err != nil {
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return "", err
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}
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// 长度检查：包含IV且为BlockSize倍数
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if len(ciphertextByte) < aes.BlockSize {
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return "", fmt.Errorf("ciphertext too short")
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}
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if len(ciphertextByte)%aes.BlockSize != 0 {
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return "", fmt.Errorf("ciphertext is not a multiple of the block size")
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}
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// 创建一个 AES 块
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block, err := aes.NewCipher([]byte(key))
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if err != nil {
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return "", err
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}
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// 提取 IV
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iv := ciphertextByte[:aes.BlockSize]
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// 提取密文
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ciphertextByteWithoutIV := ciphertextByte[aes.BlockSize:]
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if len(ciphertextByteWithoutIV) == 0 {
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return "", fmt.Errorf("ciphertext empty")
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}
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// 创建一个 CBC 模式的 AES 解密器
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mode := cipher.NewCBCDecrypter(block, iv)
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// 解密数据
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decrypted := make([]byte, len(ciphertextByteWithoutIV))
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mode.CryptBlocks(decrypted, ciphertextByteWithoutIV)
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// 去除填充字节
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padding := int(decrypted[len(decrypted)-1])
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if padding < 1 || padding > aes.BlockSize || padding > len(decrypted) {
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return "", fmt.Errorf("invalid padding")
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}
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decrypted = decrypted[:len(decrypted)-padding]
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return string(decrypted), nil
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}
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