Add T::provider() to allow user to inquire about implementation used

For block ciphers, stream ciphers, hashes, MACs, and cipher modes.
Cipher_Mode already had it, with a slightly different usage.

2 files changed, 12 insertions, 0 deletions

diff --git a/src/lib/modes/aead/gcm/gcm.cpp b/src/lib/modes/aead/gcm/gcm.cpp
index e23551cb4..590c0d0ce 100644
--- a/src/lib/modes/aead/gcm/gcm.cpp
+++ b/src/lib/modes/aead/gcm/gcm.cpp
@@ -185,6 +185,16 @@ std::string GCM_Mode::name() const
    return (m_cipher_name + "/GCM");
    }
 
+const char* GCM_Mode::provider() const
+   {
+#if defined(BOTAN_HAS_GCM_CLMUL)
+   if(CPUID::has_clmul())
+      return "clmul";
+#endif
+
+   return "base";
+   }
+
 size_t GCM_Mode::update_granularity() const
    {
    return m_BS;
diff --git a/src/lib/modes/aead/gcm/gcm.h b/src/lib/modes/aead/gcm/gcm.h
index ba0d6cad8..f0176f36a 100644
--- a/src/lib/modes/aead/gcm/gcm.h
+++ b/src/lib/modes/aead/gcm/gcm.h
@@ -36,6 +36,8 @@ class BOTAN_DLL GCM_Mode : public AEAD_Mode
       size_t tag_size() const override { return m_tag_size; }
 
       void clear() override;
+
+      const char* provider() const override;
    protected:
       GCM_Mode(BlockCipher* cipher, size_t tag_size);