Add user management

backend/internal/security/password.go

@@ -0,0 +1,13 @@
+package security
+
+import "golang.org/x/crypto/bcrypt"
+
+func HashPassword(password string) (string, error) {
+	bytes, err := bcrypt.GenerateFromPassword([]byte(password), 14)
+	return string(bytes), err
+}
+
+func CheckPasswordHash(password, hash string) bool {
+	err := bcrypt.CompareHashAndPassword([]byte(hash), []byte(password))
+	return err == nil
+}