updates

server/internal/services/crypto.go

@@ -0,0 +1,72 @@
+package services
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"os"
+)
+
+func encryptionKey() ([]byte, error) {
+	raw := os.Getenv("KEY_ENCRYPTION_KEY")
+	if raw == "" {
+		return nil, fmt.Errorf("KEY_ENCRYPTION_KEY is not set")
+	}
+	key, err := hex.DecodeString(raw)
+	if err != nil || len(key) != 32 {
+		return nil, fmt.Errorf("KEY_ENCRYPTION_KEY must be a 64-character hex string (32 bytes)")
+	}
+	return key, nil
+}
+
+func encryptPrivateKey(plaintext string) (string, error) {
+	key, err := encryptionKey()
+	if err != nil {
+		return "", err
+	}
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return "", err
+	}
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return "", err
+	}
+	nonce := make([]byte, gcm.NonceSize())
+	if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
+		return "", err
+	}
+	sealed := gcm.Seal(nonce, nonce, []byte(plaintext), nil)
+	return hex.EncodeToString(sealed), nil
+}
+
+func decryptPrivateKey(ciphertextHex string) (string, error) {
+	key, err := encryptionKey()
+	if err != nil {
+		return "", err
+	}
+	data, err := hex.DecodeString(ciphertextHex)
+	if err != nil {
+		return "", fmt.Errorf("invalid ciphertext encoding")
+	}
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return "", err
+	}
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return "", err
+	}
+	nonceSize := gcm.NonceSize()
+	if len(data) < nonceSize {
+		return "", fmt.Errorf("ciphertext too short")
+	}
+	plaintext, err := gcm.Open(nil, data[:nonceSize], data[nonceSize:], nil)
+	if err != nil {
+		return "", fmt.Errorf("decryption failed")
+	}
+	return string(plaintext), nil
+}