89 lines
2.0 KiB
Go
89 lines
2.0 KiB
Go
package aeshelper
|
|
|
|
import (
|
|
"bytes"
|
|
"crypto/aes"
|
|
"crypto/cipher"
|
|
"crypto/md5"
|
|
"crypto/rand"
|
|
"encoding/base64"
|
|
"io"
|
|
)
|
|
|
|
// Encrypt text with the passphrase
|
|
func Encrypt(text string, passphrase string) string {
|
|
salt := make([]byte, 8)
|
|
if _, err := io.ReadFull(rand.Reader, salt); err != nil {
|
|
panic(err.Error())
|
|
}
|
|
|
|
key, iv := DeriveKeyAndIv(passphrase, string(salt))
|
|
|
|
block, err := aes.NewCipher([]byte(key))
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
|
|
pad := PKCS7Padding([]byte(text), block.BlockSize())
|
|
ecb := cipher.NewCBCEncrypter(block, []byte(iv))
|
|
encrypted := make([]byte, len(pad))
|
|
ecb.CryptBlocks(encrypted, pad)
|
|
|
|
return base64.StdEncoding.EncodeToString([]byte("Salted__" + string(salt) + string(encrypted)))
|
|
}
|
|
|
|
// Decrypt encrypted text with the passphrase
|
|
func Decrypt(encrypted string, passphrase string) string {
|
|
ct, _ := base64.StdEncoding.DecodeString(encrypted)
|
|
if len(ct) < 16 || string(ct[:8]) != "Salted__" {
|
|
return ""
|
|
}
|
|
|
|
salt := ct[8:16]
|
|
ct = ct[16:]
|
|
key, iv := DeriveKeyAndIv(passphrase, string(salt))
|
|
|
|
block, err := aes.NewCipher([]byte(key))
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
|
|
cbc := cipher.NewCBCDecrypter(block, []byte(iv))
|
|
dst := make([]byte, len(ct))
|
|
cbc.CryptBlocks(dst, ct)
|
|
|
|
return string(PKCS7Trimming(dst))
|
|
}
|
|
|
|
// PKCS7Padding PKCS7Padding
|
|
func PKCS7Padding(ciphertext []byte, blockSize int) []byte {
|
|
padding := blockSize - len(ciphertext)%blockSize
|
|
padtext := bytes.Repeat([]byte{byte(padding)}, padding)
|
|
return append(ciphertext, padtext...)
|
|
}
|
|
|
|
// PKCS7Trimming PKCS7Trimming
|
|
func PKCS7Trimming(encrypt []byte) []byte {
|
|
padding := encrypt[len(encrypt)-1]
|
|
return encrypt[:len(encrypt)-int(padding)]
|
|
}
|
|
|
|
// DeriveKeyAndIv DeriveKeyAndIv
|
|
func DeriveKeyAndIv(passphrase string, salt string) (string, string) {
|
|
salted := ""
|
|
dI := ""
|
|
|
|
for len(salted) < 48 {
|
|
md := md5.New()
|
|
md.Write([]byte(dI + passphrase + salt))
|
|
dM := md.Sum(nil)
|
|
dI = string(dM[:16])
|
|
salted = salted + dI
|
|
}
|
|
|
|
key := salted[0:32]
|
|
iv := salted[32:48]
|
|
|
|
return key, iv
|
|
}
|