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package ext
import (
"bytes"
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"encoding/gob"
"fmt"
"io"
)
type Token struct {
UserID uint
Username string
}
var nonce []byte
func init() {
nonce = make([]byte, 12)
if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
fmt.Println("Erro while generating nonce " + err.Error())
panic(1)
}
}
func ReadToken(data []byte, key []byte) (*Token, error) {
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
aesgcm, err := cipher.NewGCM(block)
if err != nil {
panic(err.Error())
}
plaintext, err := aesgcm.Open(nil, nonce, data, nil)
if err != nil {
return nil, err
}
r := bytes.NewReader(plaintext)
var token Token
dec := gob.NewDecoder(r)
if err = dec.Decode(&token); err != nil {
return nil, err
}
return &token, nil
}
func WriteToken(token *Token, key []byte) ([]byte, error) {
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
aesgcm, err := cipher.NewGCM(block)
if err != nil {
return nil, err
}
var buffer bytes.Buffer
enc := gob.NewEncoder(&buffer)
if err := enc.Encode(token); err != nil {
return nil, err
}
ciphertext := aesgcm.Seal(nil, nonce, buffer.Bytes(), nil)
return ciphertext, nil
}
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