diff --git a/internal/chain/model.go b/internal/chain/model.go
index 6d261c4..3ec3bfd 100644
--- a/internal/chain/model.go
+++ b/internal/chain/model.go
@@ -17,4 +17,6 @@ type UserWallet struct {
 	Address          string         `json:"address"   gorm:"type:varchar(40);uniqueIndex;not null"`
 	EncryptedPrivKey string         `json:"-"         gorm:"type:varchar(512);not null"`
 	EncNonce         string         `json:"-"         gorm:"type:varchar(48);not null"`
+	KeyVersion       int            `json:"-"         gorm:"type:tinyint;default:1;not null"`
+	HKDFSalt         string         `json:"-"         gorm:"type:varchar(32)"` // 16 bytes hex, nullable for v1
 }