diff --git a/src/Ledger.h b/src/Ledger.h
index 665f5a145c..aa0c77583f 100644
--- a/src/Ledger.h
+++ b/src/Ledger.h
@@ -161,12 +161,21 @@ public:
 	//
 
 	static uint256 getRippleIndex(const uint160& account, const uint160& extendTo, const uint160& currency);
+
 	static uint256 getRippleIndex(const uint160& account, const uint160& extendTo)
 	{ return getRippleIndex(account, extendTo, uint160()); }
+
 	static uint256 getRippleIndex(const NewcoinAddress& account, const NewcoinAddress& extendTo,
 	 const uint160& currency)
 	{ return getRippleIndex(account.getAccountID(), extendTo.getAccountID(), currency); }
 
+	static uint160 getOfferBase(const uint160& currencyIn, const uint160& accountIn,
+		const uint160& currencyOut, const uint160& accountOut);
+
+	static uint256 getOfferIndex(const uint160& offerBase, uint64 rate, int skip = 0);
+
+	static int getOfferSkip(const uint256& offerId);
+
 	bool isCompatible(boost::shared_ptr<Ledger> other);
 	bool signLedger(std::vector<unsigned char> &signature, const LocalHanko &hanko);
 
diff --git a/src/LedgerIndex.cpp b/src/LedgerIndex.cpp
index 97d74a2306..8fd3b65708 100644
--- a/src/LedgerIndex.cpp
+++ b/src/LedgerIndex.cpp
@@ -3,8 +3,60 @@
 
 uint256 Ledger::getRippleIndex(const uint160& accountID, const uint160& extendTo, const uint160& currency)
 { // Index is 160-bit account credit extended to, 96-bit XOR of extending account and currency
-	uint256 base=getAccountRootIndex(extendTo);
-	memcpy(base.begin() + (160/8), (accountID^currency).begin(), (256/8)-(160/8));
+	uint256 base = getAccountRootIndex(extendTo);
+	memcpy(base.begin() + (160 / 8), (accountID ^ currency).begin(), (256 / 8) - (160 / 8));
 	return base;
 }
+
+uint160 Ledger::getOfferBase(const uint160& currencyIn, const uint160& accountIn,
+	const uint160& currencyOut, const uint160& accountOut)
+{
+	bool inNative = !!currencyIn;
+	bool outNative = !!currencyOut;
+
+	if (inNative && outNative)
+		throw std::runtime_error("native to native offer");
+
+	Serializer s(80);
+
+	if (inNative)
+	{
+		if (!currencyIn) throw std::runtime_error("native currencies are untied");
+		s.add32(0); // prevent collisions by ensuring different lengths
+	}
+	else
+	{
+		if (!!currencyIn) throw std::runtime_error("national currencies must be tied");
+		s.add160(currencyIn);
+		s.add160(accountIn);
+	}
+
+	if (outNative)
+	{
+		if (!currencyOut) throw std::runtime_error("native currencies are untied");
+	}
+	else
+	{
+		if (!!currencyOut) throw std::runtime_error("national currencies must be tied");
+		s.add160(currencyOut);
+		s.add160(accountOut);
+	}
+
+	return s.getRIPEMD160();
+}
+
+uint256 Ledger::getOfferIndex(const uint160& offerBase, uint64 rate, int skip)
+{ // the node for an offer index
+	Serializer s;
+	s.add160(offerBase);
+	s.add64(rate);
+	s.add32(skip);
+	return s.get256(0);
+}
+
+int Ledger::getOfferSkip(const uint256& offerId)
+{ // how far ahead we skip if an index node is full
+	return *offerId.begin();
+}
+
 // vim:ts=4