72 lines
1.5 KiB
Go
72 lines
1.5 KiB
Go
package secretbox
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"crypto/sha256"
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"encoding/base64"
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"errors"
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"io"
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)
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func DeriveKey(secret string) []byte {
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sum := sha256.Sum256([]byte(secret))
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return sum[:]
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}
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func Encrypt(key []byte, plaintext string) (string, error) {
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if plaintext == "" {
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return "", nil
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}
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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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gcm, err := cipher.NewGCM(block)
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if err != nil {
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return "", err
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}
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nonce := make([]byte, gcm.NonceSize())
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if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
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return "", err
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}
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out := gcm.Seal(nonce, nonce, []byte(plaintext), nil)
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return base64.StdEncoding.EncodeToString(out), nil
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}
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func Decrypt(key []byte, encoded string) (string, error) {
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if encoded == "" {
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return "", nil
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}
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raw, err := base64.StdEncoding.DecodeString(encoded)
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if err != nil {
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return "", err
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}
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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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gcm, err := cipher.NewGCM(block)
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if err != nil {
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return "", err
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}
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if len(raw) < gcm.NonceSize() {
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return "", errors.New("ciphertext too short")
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}
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nonce, ciphertext := raw[:gcm.NonceSize()], raw[gcm.NonceSize():]
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plain, err := gcm.Open(nil, nonce, ciphertext, nil)
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if err != nil {
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return "", err
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}
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return string(plain), nil
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}
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func RandomToken(n int) (string, error) {
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b := make([]byte, n)
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if _, err := io.ReadFull(rand.Reader, b); err != nil {
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return "", err
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}
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return base64.RawURLEncoding.EncodeToString(b), nil
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}
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