96 lines
2.1 KiB
Go
96 lines
2.1 KiB
Go
package tool
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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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"errors"
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"io"
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)
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// AES加密（CBC模式，PKCS7填充）
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func AesEncrypt(data []byte, key []byte) (string, error) {
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block, err := aes.NewCipher(key)
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if err != nil {
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return "", err
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}
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// 添加PKCS7填充
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data = pkcs7Pad(data, block.BlockSize())
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// 创建存储密文的buffer，前aes.BlockSize字节存储IV
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ciphertext := make([]byte, aes.BlockSize+len(data))
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iv := ciphertext[:aes.BlockSize]
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if _, err := io.ReadFull(rand.Reader, iv); err != nil {
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return "", err
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}
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// CBC加密
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mode := cipher.NewCBCEncrypter(block, iv)
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mode.CryptBlocks(ciphertext[aes.BlockSize:], data)
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return base64.StdEncoding.EncodeToString(ciphertext), nil
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}
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// AES解密（CBC模式，PKCS7填充）
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func AesDecrypt(encrypted string, key []byte) ([]byte, error) {
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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ciphertext, err := base64.StdEncoding.DecodeString(encrypted)
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if err != nil {
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return nil, err
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}
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if len(ciphertext) < aes.BlockSize {
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return nil, errors.New("ciphertext too short")
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}
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iv := ciphertext[:aes.BlockSize]
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ciphertext = ciphertext[aes.BlockSize:]
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if len(ciphertext)%aes.BlockSize != 0 {
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return nil, errors.New("ciphertext is not a multiple of the block size")
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}
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// CBC解密
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mode := cipher.NewCBCDecrypter(block, iv)
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mode.CryptBlocks(ciphertext, ciphertext)
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// 去除PKCS7填充
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return pkcs7Unpad(ciphertext)
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}
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// PKCS7填充
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func pkcs7Pad(data []byte, blockSize int) []byte {
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padding := blockSize - (len(data) % blockSize)
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padText := bytes.Repeat([]byte{byte(padding)}, padding)
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return append(data, padText...)
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}
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// PKCS7去除填充
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func pkcs7Unpad(data []byte) ([]byte, error) {
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length := len(data)
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if length == 0 {
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return nil, errors.New("empty input")
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}
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padding := int(data[length-1])
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if padding > length || padding == 0 {
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return nil, errors.New("invalid padding")
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}
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// 验证填充字节是否正确
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for i := length - padding; i < length; i++ {
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if int(data[i]) != padding {
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return nil, errors.New("invalid padding")
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}
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}
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return data[:length-padding], nil
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}
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