60 lines
1.4 KiB
Go
60 lines
1.4 KiB
Go
package crypto
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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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"encoding/base64"
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"errors"
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"io"
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)
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// Encrypt uses AES-GCM with a 32 byte key
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func Encrypt(key []byte, plaintext string) (string, error) {
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if len(key) != 32 {
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return "", errors.New("invalid key length")
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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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aesgcm, 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, aesgcm.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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ct := aesgcm.Seal(nonce, nonce, []byte(plaintext), nil)
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return base64.StdEncoding.EncodeToString(ct), nil
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}
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func Decrypt(key []byte, cipherText string) (string, error) {
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if len(key) != 32 {
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return "", errors.New("invalid key length")
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}
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data, err := base64.StdEncoding.DecodeString(cipherText)
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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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aesgcm, 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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nonceSize := aesgcm.NonceSize()
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if len(data) < nonceSize {
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return "", errors.New("ciphertext too short")
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}
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nonce, ct := data[:nonceSize], data[nonceSize:]
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pt, err := aesgcm.Open(nil, nonce, ct, nil)
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if err != nil {
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return "", err
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}
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return string(pt), nil
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}
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