diff --git a/stepmania/src/crypto51/mqueue.cpp b/stepmania/src/crypto51/mqueue.cpp
index 2bac976c8f..b24bc0752d 100644
--- a/stepmania/src/crypto51/mqueue.cpp
+++ b/stepmania/src/crypto51/mqueue.cpp
@@ -68,115 +68,4 @@ const byte * MessageQueue::Spy(unsigned int &contiguousSize) const
 
 // *************************************************************
 
-unsigned int EqualityComparisonFilter::MapChannel(const std::string &channel) const
-{
-	if (channel == m_firstChannel)
-		return 0;
-	else if (channel == m_secondChannel)
-		return 1;
-	else
-		return 2;
-}
-
-unsigned int EqualityComparisonFilter::ChannelPut2(const std::string &channel, const byte *inString, unsigned int length, int messageEnd, bool blocking)
-{
-	if (!blocking)
-		throw BlockingInputOnly("EqualityComparisonFilter");
-
-	unsigned int i = MapChannel(channel);
-
-	if (i == 2)
-		return Output(3, inString, length, messageEnd, blocking, channel);
-	else if (m_mismatchDetected)
-		return 0;
-	else
-	{
-		MessageQueue &q1 = m_q[i], &q2 = m_q[1-i];
-
-		if (q2.AnyMessages() && q2.MaxRetrievable() < length)
-			goto mismatch;
-
-		while (length > 0 && q2.AnyRetrievable())
-		{
-			unsigned int len = length;
-			const byte *data = q2.Spy(len);
-			len = STDMIN(len, length);
-			if (memcmp(inString, data, len) != 0)
-				goto mismatch;
-			inString += len;
-			length -= len;
-			q2.Skip(len);
-		}
-
-		q1.Put(inString, length);
-
-		if (messageEnd)
-		{
-			if (q2.AnyRetrievable())
-				goto mismatch;
-			else if (q2.AnyMessages())
-				q2.GetNextMessage();
-			else if (q2.NumberOfMessageSeries() > 0)
-				goto mismatch;
-			else
-				q1.MessageEnd();
-		}
-
-		return 0;
-
-mismatch:
-		return HandleMismatchDetected(blocking);
-	}
-}
-
-void EqualityComparisonFilter::ChannelInitialize(const std::string &channel, const NameValuePairs &parameters, int propagation)
-{
-	unsigned int i = MapChannel(channel);
-
-	if (i == 2)
-		PropagateInitialize(parameters, propagation, channel);
-	else
-	{
-		m_q[i].Initialize();
-		m_mismatchDetected = false;
-	}
-}
-
-bool EqualityComparisonFilter::ChannelMessageSeriesEnd(const std::string &channel, int propagation, bool blocking)
-{
-	unsigned int i = MapChannel(channel);
-
-	if (i == 2)
-	{
-		OutputMessageSeriesEnd(4, propagation, blocking, channel);
-		return false;
-	}
-	else if (m_mismatchDetected)
-		return false;
-	else
-	{
-		MessageQueue &q1 = m_q[i], &q2 = m_q[1-i];
-
-		if (q2.AnyRetrievable() || q2.AnyMessages())
-			goto mismatch;
-		else if (q2.NumberOfMessageSeries() > 0)
-			return Output(2, (const byte *)"\1", 1, 0, blocking) != 0;
-		else
-			q1.MessageSeriesEnd();
-
-		return false;
-
-mismatch:
-		return HandleMismatchDetected(blocking);
-	}
-}
-
-bool EqualityComparisonFilter::HandleMismatchDetected(bool blocking)
-{
-	m_mismatchDetected = true;
-	if (m_throwIfNotEqual)
-		throw MismatchDetected();
-	return Output(1, (const byte *)"\0", 1, 0, blocking) != 0;
-}
-
 NAMESPACE_END
diff --git a/stepmania/src/crypto51/mqueue.h b/stepmania/src/crypto51/mqueue.h
index edc701a75e..eed93122d9 100644
--- a/stepmania/src/crypto51/mqueue.h
+++ b/stepmania/src/crypto51/mqueue.h
@@ -61,31 +61,6 @@ private:
 };
 
 
-//! A filter that checks messages on two channels for equality
-class EqualityComparisonFilter : public Unflushable<Multichannel<Filter> >
-{
-public:
-	struct MismatchDetected : public Exception {MismatchDetected() : Exception(DATA_INTEGRITY_CHECK_FAILED, "EqualityComparisonFilter: did not receive the same data on two channels") {}};
-
-	/*! if throwIfNotEqual is false, this filter will output a '\0' byte when it detects a mismatch, '\1' otherwise */
-	EqualityComparisonFilter(BufferedTransformation *attachment=NULL, bool throwIfNotEqual=true, const std::string &firstChannel="0", const std::string &secondChannel="1")
-		: Unflushable<Multichannel<Filter> >(attachment), m_throwIfNotEqual(throwIfNotEqual), m_mismatchDetected(false)
-		, m_firstChannel(firstChannel), m_secondChannel(secondChannel) {}
-
-	unsigned int ChannelPut2(const std::string &channel, const byte *begin, unsigned int length, int messageEnd, bool blocking);
-
-	void ChannelInitialize(const std::string &channel, const NameValuePairs &parameters=g_nullNameValuePairs, int propagation=-1);
-	bool ChannelMessageSeriesEnd(const std::string &channel, int propagation=-1, bool blocking=true);
-
-private:
-	unsigned int MapChannel(const std::string &channel) const;
-	bool HandleMismatchDetected(bool blocking);
-
-	bool m_throwIfNotEqual, m_mismatchDetected;
-	std::string m_firstChannel, m_secondChannel;
-	MessageQueue m_q[2];
-};
-
 NAMESPACE_END
 
 NAMESPACE_BEGIN(std)