Add key length multiple

2 files changed, 8 insertions, 5 deletions

diff --git a/src/algo_base/key_spec.h b/src/algo_base/key_spec.h
index 73cd9126f..15881c1a6 100644
--- a/src/algo_base/key_spec.h
+++ b/src/algo_base/key_spec.h
@@ -79,6 +79,13 @@ class BOTAN_DLL Key_Length_Specification
          return keylen_mod;
          }
 
+      Key_Length_Specification multiple(size_t n) const
+         {
+         return Key_Length_Specification(n * min_keylen,
+                                         n * max_keylen,
+                                         n * keylen_mod);
+         }
+
    private:
       size_t min_keylen, max_keylen, keylen_mod;
    };
diff --git a/src/modes/xts/xts.cpp b/src/modes/xts/xts.cpp
index dffba824e..80b7ed7f3 100644
--- a/src/modes/xts/xts.cpp
+++ b/src/modes/xts/xts.cpp
@@ -83,11 +83,7 @@ size_t XTS_Mode::minimum_final_size() const
 
 Key_Length_Specification XTS_Mode::key_spec() const
    {
-   const Key_Length_Specification spec = cipher().key_spec();
-
-   return Key_Length_Specification(2*spec.minimum_keylength(),
-                                   2*spec.maximum_keylength(),
-                                   2*spec.keylength_multiple());
+   return cipher().key_spec().multiple(2);
    }
 
 size_t XTS_Mode::default_nonce_size() const