Cleanups/random changes in the stream cipher code:

Remove encrypt, decrypt - replace by cipher() and cipher1()

Remove seek() - not well supported/tested, I want to redo with a new interface
once CTR and OFB modes become stream ciphers.

Rename resync to set_iv()

Remove StreamCipher::IV_LENGTH and add StreamCipher::valid_iv_length() to
allow multiple IV lengths (as for instance Turing allows, as would Salsa20
if XSalsa20 were supported).

2 files changed, 12 insertions, 8 deletions

diff --git a/src/stream/salsa20/salsa20.cpp b/src/stream/salsa20/salsa20.cpp
index 9c7c811f0..a147cdb45 100644
--- a/src/stream/salsa20/salsa20.cpp
+++ b/src/stream/salsa20/salsa20.cpp
@@ -162,15 +162,15 @@ void Salsa20::key_schedule(const byte key[], u32bit length)
       }
 
    const byte ZERO[8] = { 0 };
-   resync(ZERO, sizeof(ZERO));
+   set_iv(ZERO, sizeof(ZERO));
    }
 
 /*
 * Return the name of this type
 */
-void Salsa20::resync(const byte iv[], u32bit length)
+void Salsa20::set_iv(const byte iv[], u32bit length)
    {
-   if(length != IV_LENGTH)
+   if(!valid_iv_length(length))
       throw Invalid_IV_Length(name(), length);
 
    state[6] = load_le<u32bit>(iv, 0);
@@ -207,7 +207,7 @@ void Salsa20::clear() throw()
 /*
 * Salsa20 Constructor
 */
-Salsa20::Salsa20() : StreamCipher(16, 32, 16, 8)
+Salsa20::Salsa20() : StreamCipher(16, 32, 16)
    {
    clear();
    }
diff --git a/src/stream/salsa20/salsa20.h b/src/stream/salsa20/salsa20.h
index 3dbfddb50..a3e9a3706 100644
--- a/src/stream/salsa20/salsa20.h
+++ b/src/stream/salsa20/salsa20.h
@@ -18,17 +18,21 @@ namespace Botan {
 class BOTAN_DLL Salsa20 : public StreamCipher
    {
    public:
+      void cipher(const byte in[], byte out[], u32bit length);
+
+      void set_iv(const byte iv[], u32bit iv_len);
+
+      bool valid_iv_length(u32bit iv_len) const
+         { return (iv_len == 8); }
+
       void clear() throw();
       std::string name() const;
       StreamCipher* clone() const { return new Salsa20; }
 
-      void resync(const byte[], u32bit);
-
       Salsa20();
       ~Salsa20() { clear(); }
    private:
-      void cipher(const byte[], byte[], u32bit);
-      void key_schedule(const byte[], u32bit);
+      void key_schedule(const byte key[], u32bit key_len);
 
       SecureBuffer<u32bit, 16> state;