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).

10 files changed, 64 insertions, 92 deletions

diff --git a/src/stream/arc4/arc4.h b/src/stream/arc4/arc4.h
index aa2cea7fe..3f92fa914 100644
--- a/src/stream/arc4/arc4.h
+++ b/src/stream/arc4/arc4.h
@@ -19,13 +19,16 @@ namespace Botan {
 class BOTAN_DLL ARC4 : public StreamCipher
    {
    public:
+      void cipher(const byte in[], byte out[], u32bit length);
+
       void clear() throw();
       std::string name() const;
+
       StreamCipher* clone() const { return new ARC4(SKIP); }
+
       ARC4(u32bit = 0);
       ~ARC4() { clear(); }
    private:
-      void cipher(const byte[], byte[], u32bit);
       void key_schedule(const byte[], u32bit);
       void generate();
 
diff --git a/src/stream/info.txt b/src/stream/info.txt
index 295c73708..f8f4b22d5 100644
--- a/src/stream/info.txt
+++ b/src/stream/info.txt
@@ -6,7 +6,6 @@ define STREAM_CIPHER
 
 <add>
 stream_cipher.h
-stream_cipher.cpp
 </add>
 
 <requires>
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;
 
diff --git a/src/stream/stream_cipher.cpp b/src/stream/stream_cipher.cpp
deleted file mode 100644
index 68bb5d4f0..000000000
--- a/src/stream/stream_cipher.cpp
+++ /dev/null
@@ -1,30 +0,0 @@
-/**
-* Stream Cipher Default Implementation for IV and Seek
-* (C) 1999-2007 Jack Lloyd
-*
-* Distributed under the terms of the Botan license
-*/
-
-#include <botan/stream_cipher.h>
-
-namespace Botan {
-
-/*
-* Default StreamCipher Resync Operation
-*/
-void StreamCipher::resync(const byte[], u32bit length)
-   {
-   if(length)
-      throw Exception("The stream cipher " + name() +
-                      " does not support resyncronization");
-   }
-
-/*
-* Default StreamCipher Seek Operation
-*/
-void StreamCipher::seek(u32bit)
-   {
-   throw Exception("The stream cipher " + name() + " does not support seek()");
-   }
-
-}
diff --git a/src/stream/stream_cipher.h b/src/stream/stream_cipher.h
index 8ea359131..d6abb37fc 100644
--- a/src/stream/stream_cipher.h
+++ b/src/stream/stream_cipher.h
@@ -18,53 +18,40 @@ namespace Botan {
 class BOTAN_DLL StreamCipher : public SymmetricAlgorithm
    {
    public:
-      const u32bit IV_LENGTH;
-
-      /**
-      * Encrypt a message.
-      * @param i the plaintext
-      * @param o the byte array to hold the output, i.e. the ciphertext
-      * @param len the length of both i and o
-      */
-      void encrypt(const byte i[], byte o[], u32bit len) { cipher(i, o, len); }
-
       /**
-      * Decrypt a message.
-      * @param i the ciphertext to decrypt
-      * @param o the byte array to hold the output, i.e. the plaintext
-      * @param len the length of both i and o
+      * Encrypt or decrypt a message
+      * @param in the plaintext
+      * @param out the byte array to hold the output, i.e. the ciphertext
+      * @param len the length of both in and out in bytes
       */
-      void decrypt(const byte i[], byte o[], u32bit len) { cipher(i, o, len); }
+      virtual void cipher(const byte in[], byte out[], u32bit len) = 0;
 
       /**
-      * Encrypt a message.
-      * @param in the plaintext as input, after the function has
-      * returned it will hold the ciphertext
-
-      * @param len the length of in
+      * Encrypt or decrypt a message
+      * @param buf the plaintext / ciphertext
+      * @param len the length of buf in bytes
       */
-      void encrypt(byte in[], u32bit len) { cipher(in, in, len); }
-
-      /**
-      * Decrypt a message.
-      * @param in the ciphertext as input, after the function has
-      * returned it will hold the plaintext
-      * @param len the length of in
-      */
-      void decrypt(byte in[], u32bit len) { cipher(in, in, len); }
+      void cipher1(byte buf[], u32bit len)
+         { cipher(buf, buf, len); }
 
       /**
       * Resync the cipher using the IV
       * @param iv the initialization vector
       * @param iv_len the length of the IV in bytes
       */
-      virtual void resync(const byte iv[], u32bit iv_len);
+      virtual void set_iv(const byte[], u32bit iv_len)
+         {
+         if(iv_len)
+            throw Exception("The stream cipher " + name() +
+                            " does not support resyncronization");
+         }
 
       /**
-      * Seek ahead in the stream.
-      * @param len the length to seek ahead.
+      * @param iv_len the length of the IV in bytes
+      * @return if the length is valid for this algorithm
       */
-      virtual void seek(u32bit len);
+      virtual bool valid_iv_length(u32bit iv_len) const
+         { return (iv_len == 0); }
 
       /**
       * Get a new object representing the same algorithm as *this
@@ -76,15 +63,15 @@ class BOTAN_DLL StreamCipher : public SymmetricAlgorithm
       */
       virtual void clear() throw() = 0;
 
-      StreamCipher(u32bit key_min, u32bit key_max = 0,
-                   u32bit key_mod = 1,
-                   u32bit iv_len = 0) :
-         SymmetricAlgorithm(key_min, key_max, key_mod),
-         IV_LENGTH(iv_len) {}
+      /**
+      * StreamCipher constructor
+      */
+      StreamCipher(u32bit key_min,
+                   u32bit key_max = 0,
+                   u32bit key_mod = 1) :
+         SymmetricAlgorithm(key_min, key_max, key_mod) {}
 
       virtual ~StreamCipher() {}
-   private:
-      virtual void cipher(const byte[], byte[], u32bit) = 0;
    };
 
 }
diff --git a/src/stream/turing/turing.cpp b/src/stream/turing/turing.cpp
index 1e2203480..8336a70a7 100644
--- a/src/stream/turing/turing.cpp
+++ b/src/stream/turing/turing.cpp
@@ -257,15 +257,15 @@ void Turing::key_schedule(const byte key[], u32bit length)
       S3[i] = (W3 & 0xFFFFFF00) | C3;
       }
 
-   resync(0, 0);
+   set_iv(0, 0);
    }
 
 /*
 * Resynchronization
 */
-void Turing::resync(const byte iv[], u32bit length)
+void Turing::set_iv(const byte iv[], u32bit length)
    {
-   if(length % 4 != 0 || length > 16)
+   if(!valid_iv_length(length))
       throw Invalid_IV_Length(name(), length);
 
    SecureVector<u32bit> IV(length / 4);
diff --git a/src/stream/turing/turing.h b/src/stream/turing/turing.h
index 455d3c612..59290f640 100644
--- a/src/stream/turing/turing.h
+++ b/src/stream/turing/turing.h
@@ -18,14 +18,18 @@ namespace Botan {
 class BOTAN_DLL Turing : public StreamCipher
    {
    public:
+      void cipher(const byte in[], byte out[], u32bit length);
+      void set_iv(const byte[], u32bit);
+
+      bool valid_iv_length(u32bit iv_len) const
+         { return (iv_len % 4 == 0 && iv_len <= 16); }
+
       void clear() throw();
       std::string name() const { return "Turing"; }
       StreamCipher* clone() const { return new Turing; }
       Turing() : StreamCipher(4, 32, 4) { position = 0; }
    private:
-      void cipher(const byte[], byte[], u32bit);
       void key_schedule(const byte[], u32bit);
-      void resync(const byte[], u32bit);
       void generate();
 
       static u32bit fixedS(u32bit);
diff --git a/src/stream/wid_wake/wid_wake.cpp b/src/stream/wid_wake/wid_wake.cpp
index 1dc0fd7f9..56f938fac 100644
--- a/src/stream/wid_wake/wid_wake.cpp
+++ b/src/stream/wid_wake/wid_wake.cpp
@@ -110,16 +110,17 @@ void WiderWake_41_BE::key_schedule(const byte key[], u32bit)
    T[X] = Z;
 
    position = 0;
-   const byte iv[8] = { 0 };
-   resync(iv, 8);
+
+   const byte ZEROS[8] = { 0 };
+   set_iv(ZEROS, sizeof(ZEROS));
    }
 
 /*
 * Resynchronization
 */
-void WiderWake_41_BE::resync(const byte iv[], u32bit length)
+void WiderWake_41_BE::set_iv(const byte iv[], u32bit length)
    {
-   if(length != 8)
+   if(!valid_iv_length(length))
       throw Invalid_IV_Length(name(), length);
 
    for(u32bit j = 0; j != 4; ++j)
diff --git a/src/stream/wid_wake/wid_wake.h b/src/stream/wid_wake/wid_wake.h
index 4720afdb2..a037a056e 100644
--- a/src/stream/wid_wake/wid_wake.h
+++ b/src/stream/wid_wake/wid_wake.h
@@ -18,14 +18,18 @@ namespace Botan {
 class BOTAN_DLL WiderWake_41_BE : public StreamCipher
    {
    public:
+      void cipher(const byte[], byte[], u32bit);
+      void set_iv(const byte[], u32bit);
+
+      bool valid_iv_length(u32bit iv_len) const
+         { return (iv_len == 8); }
+
       void clear() throw();
       std::string name() const { return "WiderWake4+1-BE"; }
       StreamCipher* clone() const { return new WiderWake_41_BE; }
-      WiderWake_41_BE() : StreamCipher(16, 16, 1, 8) {}
+      WiderWake_41_BE() : StreamCipher(16, 16, 1) {}
    private:
-      void cipher(const byte[], byte[], u32bit);
       void key_schedule(const byte[], u32bit);
-      void resync(const byte[], u32bit);
 
       void generate(u32bit);