Use ROUNDS constant for ChaChaTLS

2 files changed, 9 insertions, 13 deletions

diff --git a/chacha.cpp b/chacha.cpp
index 9d0f357e..321ebbaf 100644
--- a/chacha.cpp
+++ b/chacha.cpp
@@ -384,7 +384,7 @@ void ChaChaTLS_Policy::CipherSetKey(const NameValuePairs &params, const byte *ke
     CRYPTOPP_ASSERT(key); CRYPTOPP_ASSERT(length == 32);

 

     // ChaChaTLS is always 20 rounds. Fetch Rounds() to avoid a spurious failure.

-    int rounds = params.GetIntValueWithDefault(Name::Rounds(), m_rounds);

+    int rounds = params.GetIntValueWithDefault(Name::Rounds(), ROUNDS);

     if (rounds != 20)

         throw InvalidRounds(ChaChaTLS::StaticAlgorithmName(), rounds);

 

@@ -423,12 +423,6 @@ void ChaChaTLS_Policy::CipherResynchronize(byte *keystreamBuffer, const byte *IV
     get(m_state[13])(m_state[14])(m_state[15]);

 }

 

-void ChaChaTLS_Policy::CipherResynchronize(byte *keystreamBuffer, word32 initialBlock, const byte *IV, size_t length)

-{

-    m_state[16] = initialBlock;

-    this->CipherResynchronize(keystreamBuffer, IV, length);

-}

-

 void ChaChaTLS_Policy::SeekToIteration(lword iterationCount)

 {

     // Should we throw here??? If the initial block counter is

@@ -454,14 +448,15 @@ void ChaChaTLS_Policy::OperateKeystream(KeystreamOperation operation,
 {

     word32 discard=0;

     ChaCha_OperateKeystream(operation, m_state, m_state[12], discard,

-            m_rounds, output, input, iterationCount);

+            ROUNDS, output, input, iterationCount);

 

     // If this fires it means ChaCha_OperateKeystream generated a counter

     // block carry that was discarded. The problem is, the RFC does not

     // specify what should happen when the counter block wraps. All we can

     // do is inform the user that something bad may happen because we don't

     // know what we should do.

-    // Also see https://github.com/weidai11/cryptopp/issues/790.

+    // Also see https://github.com/weidai11/cryptopp/issues/790 and

+    // https://mailarchive.ietf.org/arch/msg/cfrg/gsOnTJzcbgG6OqD8Sc0GO5aR_tU

     CRYPTOPP_ASSERT(discard==0);

 }

 

diff --git a/chacha.h b/chacha.h
index 9be96253..9551b344 100644
--- a/chacha.h
+++ b/chacha.h
@@ -114,7 +114,6 @@ protected:
     void CipherSetKey(const NameValuePairs &params, const byte *key, size_t length);

     void OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount);

     void CipherResynchronize(byte *keystreamBuffer, const byte *IV, size_t length);

-	void CipherResynchronize(byte *keystreamBuffer, word32 initialBlock, const byte *IV, size_t length);

     bool CipherIsRandomAccess() const {return true;}

     void SeekToIteration(lword iterationCount);

     unsigned int GetAlignment() const;

@@ -124,7 +123,7 @@ protected:
     std::string AlgorithmProvider() const;

 

     FixedSizeAlignedSecBlock<word32, 16+1> m_state;

-    CRYPTOPP_CONSTANT(m_rounds = ChaChaTLS_Info::ROUNDS)

+    CRYPTOPP_CONSTANT(ROUNDS = ChaChaTLS_Info::ROUNDS)

 };

 

 /// \brief ChaCha-TLS stream cipher

@@ -135,8 +134,10 @@ protected:
 ///   <tt>TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>,

 ///   <tt>TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256</tt>, and

 ///   <tt>TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>.

-/// \sa <a href="https://tools.ietf.org/html/rfc8439">ChaCha20 and Poly1305 for

-///   IETF Protocols</a> and <A HREF="https://github.com/weidai11/cryptopp/issues/790">Issue

+/// \sa <a href="https://tools.ietf.org/html/rfc8439">RFC 8439, ChaCha20 and

+///   Poly1305 for IETF Protocols</a>, <A HREF="https://mailarchive.ietf.org/arch/msg/cfrg/gsOnTJzcbgG6OqD8Sc0GO5aR_tU">How

+///   to handle block counter wrap in IETF's ChaCha algorithm?</A> and

+///   <A HREF="https://github.com/weidai11/cryptopp/issues/790">Issue

 ///   790, ChaChaTLS results when counter block wraps</A>.

 /// \since Crypto++ 8.1

 struct ChaChaTLS : public ChaChaTLS_Info, public SymmetricCipherDocumentation