diff --git a/libwhisper/BloomFilter.h b/libwhisper/BloomFilter.h
index 32ac15043..02cc80505 100644
--- a/libwhisper/BloomFilter.h
+++ b/libwhisper/BloomFilter.h
@@ -88,7 +88,7 @@ template <unsigned N>
 bool TopicBloomFilterBase<N>::isBitSet(FixedHash<N> const& _h, unsigned _index)
 {
 	unsigned iByte = _index / 8;
-	unsigned iBit = _index & 0x7;
+	unsigned iBit = _index % 8;
 	return (_h[iByte] & c_powerOfTwoBitMmask[iBit]) != 0;
 }
 
@@ -96,7 +96,7 @@ template <unsigned N>
 void TopicBloomFilterBase<N>::setBit(FixedHash<N>& _h, unsigned _index)
 {
 	unsigned iByte = _index / 8;
-	unsigned iBit = _index & 0x7;
+	unsigned iBit = _index % 8;
 	_h[iByte] |= c_powerOfTwoBitMmask[iBit];
 }
 
diff --git a/libwhisper/Message.cpp b/libwhisper/Message.cpp
index 435811a3b..dd72ff734 100644
--- a/libwhisper/Message.cpp
+++ b/libwhisper/Message.cpp
@@ -170,7 +170,7 @@ void Envelope::proveWork(unsigned _ms)
 	chrono::high_resolution_clock::time_point then = chrono::high_resolution_clock::now() + chrono::milliseconds(_ms);
 	while (chrono::high_resolution_clock::now() < then)
 		// do it rounds of 1024 for efficiency
-		for (unsigned i = 0; i < 1024; ++i)
+		for (unsigned i = 0; i < 1024; ++i, ++d[1])
 		{
 			auto fbs = dev::sha3(chuck).firstBitSet();
 			if (fbs > bestBitSet)
@@ -178,8 +178,6 @@ void Envelope::proveWork(unsigned _ms)
 				bestBitSet = fbs;
 				m_nonce = (h256::Arith)d[1];
 			}
-
-			incrementHash(d[1]);
 		}
 }
 
diff --git a/libwhisper/Message.h b/libwhisper/Message.h
index fb89576e9..ae61f210a 100644
--- a/libwhisper/Message.h
+++ b/libwhisper/Message.h
@@ -81,7 +81,6 @@ public:
 	void proveWork(unsigned _ms);
 
 	bool matchesBloomFilter(TopicBloomFilterHash const& f) const;
-	static void incrementHash(h256& _h) { for (unsigned i = h256::size; i > 0 && !++_h[--i]; ) {} }
 
 private:
 	Envelope(unsigned _exp, unsigned _ttl, AbridgedTopics const& _topic): m_expiry(_exp), m_ttl(_ttl), m_topic(_topic) {}