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package crypto
import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"crypto/sha256"
"encoding/base64"
"fmt"
"io"
"lain/config"
)
func getKey() []byte {
hash := sha256.Sum256([]byte(config.Server.AppSecret))
return hash[:]
}
func Encrypt(plaintext string) (string, error) {
key := getKey()
block, err := aes.NewCipher(key)
if err != nil {
return "", err
}
gcm, err := cipher.NewGCM(block)
if err != nil {
return "", err
}
nonce := make([]byte, gcm.NonceSize())
if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
return "", err
}
ciphertext := gcm.Seal(nonce, nonce, []byte(plaintext), nil)
return base64.URLEncoding.EncodeToString(ciphertext), nil
}
func Decrypt(ciphertext string) (string, error) {
key := getKey()
ciphertextBytes, err := base64.URLEncoding.DecodeString(ciphertext)
if err != nil {
return "", err
}
block, err := aes.NewCipher(key)
if err != nil {
return "", err
}
gcm, err := cipher.NewGCM(block)
if err != nil {
return "", err
}
nonceSize := gcm.NonceSize()
if len(ciphertextBytes) < nonceSize {
return "", fmt.Errorf("ciphertext too short")
}
nonce, ciphertextBytes := ciphertextBytes[:nonceSize], ciphertextBytes[nonceSize:]
plaintextBytes, err := gcm.Open(nil, nonce, ciphertextBytes, nil)
if err != nil {
return "", err
}
return string(plaintextBytes), nil
}
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