Adding StreamCipher::seek interface, supporting seek in ChaCha, and also adding ChaCha8 support

2 files changed, 6 insertions, 0 deletions

diff --git a/src/lib/stream/rc4/rc4.cpp b/src/lib/stream/rc4/rc4.cpp
index 895f38091..a4dea9e2b 100644
--- a/src/lib/stream/rc4/rc4.cpp
+++ b/src/lib/stream/rc4/rc4.cpp
@@ -113,4 +113,8 @@ void RC4::clear()
 */
 RC4::RC4(size_t s) : m_SKIP(s) {}
 
+void RC4::seek(u64bit)
+   {
+   throw Exception("RC4 does not support seeking");
+   }
 }
diff --git a/src/lib/stream/rc4/rc4.h b/src/lib/stream/rc4/rc4.h
index f166a2772..88798fae6 100644
--- a/src/lib/stream/rc4/rc4.h
+++ b/src/lib/stream/rc4/rc4.h
@@ -39,6 +39,8 @@ class BOTAN_DLL RC4 final : public StreamCipher
       explicit RC4(size_t skip = 0);
 
       ~RC4() { clear(); }
+
+      void seek(u64bit offset) override;
    private:
       void key_schedule(const byte[], size_t) override;
       void generate();