first commit

crypto/crypto.go

@@ -0,0 +1,62 @@
+package crypto
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"fmt"
+	"io"
+)
+
+func Encrypt(text string, key []byte) (string, error) {
+	plaintext := []byte(text)
+
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return "", err
+	}
+
+	aesGCM, err := cipher.NewGCM(block)
+	if err != nil {
+		return "", err
+	}
+
+	nonce := make([]byte, aesGCM.NonceSize())
+	if _, err = io.ReadFull(rand.Reader, nonce); err != nil {
+		return "", err
+	}
+
+	ciphertext := aesGCM.Seal(nonce, nonce, plaintext, nil)
+	return base64.StdEncoding.EncodeToString(ciphertext), nil
+}
+
+func Decrypt(encrypted string, key []byte) (string, error) {
+	data, err := base64.StdEncoding.DecodeString(encrypted)
+	if err != nil {
+		return "", err
+	}
+
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return "", err
+	}
+
+	aesGCM, err := cipher.NewGCM(block)
+	if err != nil {
+		return "", err
+	}
+
+	nonceSize := aesGCM.NonceSize()
+	if len(data) < nonceSize {
+		return "", fmt.Errorf("ciphertext too short")
+	}
+
+	nonce, ciphertext := data[:nonceSize], data[nonceSize:]
+	plaintext, err := aesGCM.Open(nil, nonce, ciphertext, nil)
+	if err != nil {
+		return "", err
+	}
+
+	return string(plaintext), nil
+}