1 files changed, 47 insertions, 0 deletions
diff --git a/src/lib/modes/cipher_mode.h b/src/lib/modes/cipher_mode.h
index 691852214..19c0af150 100644
--- a/src/lib/modes/cipher_mode.h
+++ b/src/lib/modes/cipher_mode.h
@@ -9,6 +9,7 @@
 #define BOTAN_CIPHER_MODE_H__
 
 #include <botan/transform.h>
+#include <botan/stream_cipher.h>
 
 namespace Botan {
 
@@ -25,6 +26,52 @@ class BOTAN_DLL Cipher_Mode : public Keyed_Transform
       virtual bool authenticated() const { return false; }
    };
 
+class BOTAN_DLL Stream_Cipher_Mode : public Cipher_Mode
+   {
+   public:
+      Stream_Cipher_Mode(StreamCipher* cipher) : m_cipher(cipher) {}
+
+      void update(secure_vector<byte>& buf, size_t offset) override
+         {
+         if(offset < buf.size())
+            m_cipher->cipher1(&buf[offset], buf.size() - offset);
+         }
+
+      void finish(secure_vector<byte>& buf, size_t offset) override
+         { return update(buf, offset); }
+
+      size_t output_length(size_t input_length) const override { return input_length; }
+
+      size_t update_granularity() const override { return 64; /* arbitrary */ }
+
+      size_t minimum_final_size() const override { return 0; }
+
+      size_t default_nonce_length() const override { return 0; }
+
+      bool valid_nonce_length(size_t nonce_len) const override
+         { return m_cipher->valid_iv_length(nonce_len); }
+
+      Key_Length_Specification key_spec() const override { return m_cipher->key_spec(); }
+
+      std::string name() const override { return m_cipher->name(); }
+
+      void clear() override { return m_cipher->clear(); }
+
+   private:
+      secure_vector<byte> start_raw(const byte nonce[], size_t nonce_len) override
+         {
+         m_cipher->set_iv(nonce, nonce_len);
+         return secure_vector<byte>();
+         }
+
+      void key_schedule(const byte key[], size_t length)
+         {
+         m_cipher->set_key(key, length);
+         }
+
+      std::unique_ptr<StreamCipher> m_cipher;
+   };
+
 BOTAN_DLL Cipher_Mode* get_cipher_mode(const std::string& algo_spec, Cipher_Dir direction);
 
 }