From f044cba41a28bc84f960d3e2a4b23ced4fbb6351 Mon Sep 17 00:00:00 2001
From: Matt Corallo <git@bluematt.me>
Date: Mon, 29 Feb 2016 13:44:46 -0500
Subject: [PATCH] Add base58 support for blinded addresses

---
 src/base58.cpp      | 45 +++++++++++++++++++++++++++++++++++++++++++++
 src/base58.h        |  5 +++++
 src/chainparams.cpp |  3 +++
 src/chainparams.h   |  1 +
 4 files changed, 54 insertions(+)

diff --git a/src/base58.cpp b/src/base58.cpp
index d1d60a6f1d..80890e6153 100644
--- a/src/base58.cpp
+++ b/src/base58.cpp
@@ -240,13 +240,49 @@ bool CBitcoinAddress::Set(const CTxDestination& dest)
     return boost::apply_visitor(CBitcoinAddressVisitor(this), dest);
 }
 
+CBitcoinAddress& CBitcoinAddress::AddBlindingKey(const CPubKey& pubkey)
+{
+    if (!pubkey.IsValid()) {
+        return *this;
+    }
+    assert(pubkey.size() == 33);
+    assert(!IsBlinded());
+    std::vector<unsigned char> data = vchVersion;
+    data.insert(data.end(), pubkey.begin(), pubkey.end());
+    data.insert(data.end(), vchData.begin(), vchData.end());
+    SetData(Params().Base58Prefix(CChainParams::BLINDED_ADDRESS), &data[0], data.size());
+    return *this;
+}
+
+CPubKey CBitcoinAddress::GetBlindingKey() const
+{
+    assert(IsBlinded());
+    CPubKey pubkey(&vchData[1], &vchData[34]);
+    return pubkey;
+}
+
+bool CBitcoinAddress::IsBlinded(const CChainParams& params) const
+{
+    return (vchVersion == params.Base58Prefix(CChainParams::BLINDED_ADDRESS) && vchData.size() > 34);
+}
+
 bool CBitcoinAddress::IsValid() const
 {
     return IsValid(Params());
 }
 
+CBitcoinAddress CBitcoinAddress::GetUnblinded() const
+{
+    CBitcoinAddress subaddr;
+    subaddr.SetData(std::vector<unsigned char>(&vchData[0], &vchData[1]), &vchData[34], vchData.size() - 34);
+    return subaddr;
+}
+
 bool CBitcoinAddress::IsValid(const CChainParams& params) const
 {
+    if (IsBlinded(params)) {
+        return GetUnblinded().IsValid(params);
+    }
     bool fCorrectSize = vchData.size() == 20;
     bool fKnownVersion = vchVersion == params.Base58Prefix(CChainParams::PUBKEY_ADDRESS) ||
                          vchVersion == params.Base58Prefix(CChainParams::SCRIPT_ADDRESS);
@@ -255,6 +291,9 @@ bool CBitcoinAddress::IsValid(const CChainParams& params) const
 
 CTxDestination CBitcoinAddress::Get() const
 {
+    if (IsBlinded()) {
+        return GetUnblinded().Get();
+    }
     if (!IsValid())
         return CNoDestination();
     uint160 id;
@@ -269,6 +308,9 @@ CTxDestination CBitcoinAddress::Get() const
 
 bool CBitcoinAddress::GetKeyID(CKeyID& keyID) const
 {
+    if (IsBlinded()) {
+        return GetUnblinded().GetKeyID(keyID);
+    }
     if (!IsValid() || vchVersion != Params().Base58Prefix(CChainParams::PUBKEY_ADDRESS))
         return false;
     uint160 id;
@@ -279,6 +321,9 @@ bool CBitcoinAddress::GetKeyID(CKeyID& keyID) const
 
 bool CBitcoinAddress::IsScript() const
 {
+    if (IsBlinded()) {
+        return GetUnblinded().IsScript();
+    }
     return IsValid() && vchVersion == Params().Base58Prefix(CChainParams::SCRIPT_ADDRESS);
 }
 
diff --git a/src/base58.h b/src/base58.h
index cccebc9e0e..23700a92d5 100644
--- a/src/base58.h
+++ b/src/base58.h
@@ -117,6 +117,11 @@ public:
     CTxDestination Get() const;
     bool GetKeyID(CKeyID &keyID) const;
     bool IsScript() const;
+
+    CBitcoinAddress& AddBlindingKey(const CPubKey &pubkey);
+    CPubKey GetBlindingKey() const;
+    CBitcoinAddress GetUnblinded() const;
+    bool IsBlinded(const CChainParams& params = Params()) const;
 };
 
 /**
diff --git a/src/chainparams.cpp b/src/chainparams.cpp
index bcabcc0dc9..1f23e2401a 100644
--- a/src/chainparams.cpp
+++ b/src/chainparams.cpp
@@ -105,6 +105,7 @@ public:
         };
         base58Prefixes[PUBKEY_ADDRESS] = std::vector<unsigned char>(1,111);
         base58Prefixes[SCRIPT_ADDRESS] = std::vector<unsigned char>(1,196);
+        base58Prefixes[BLINDED_ADDRESS]= std::vector<unsigned char>(1,26);
         base58Prefixes[SECRET_KEY] =     std::vector<unsigned char>(1,239);
         base58Prefixes[EXT_PUBLIC_KEY] = boost::assign::list_of(0x04)(0x35)(0x87)(0xCF).convert_to_container<std::vector<unsigned char> >();
         base58Prefixes[EXT_SECRET_KEY] = boost::assign::list_of(0x04)(0x35)(0x83)(0x94).convert_to_container<std::vector<unsigned char> >();
@@ -121,6 +122,7 @@ public:
 
         base58Prefixes[PUBKEY_ADDRESS] = std::vector<unsigned char>(1,0);
         base58Prefixes[SCRIPT_ADDRESS] = std::vector<unsigned char>(1,5);
+        base58Prefixes[BLINDED_ADDRESS]= std::vector<unsigned char>(1,11);
         base58Prefixes[SECRET_KEY] =     std::vector<unsigned char>(1,128);
         base58Prefixes[EXT_PUBLIC_KEY] = boost::assign::list_of(0x04)(0x88)(0xB2)(0x1E).convert_to_container<std::vector<unsigned char> >();
         base58Prefixes[EXT_SECRET_KEY] = boost::assign::list_of(0x04)(0x88)(0xAD)(0xE4).convert_to_container<std::vector<unsigned char> >();
@@ -186,6 +188,7 @@ public:
         };
         base58Prefixes[PUBKEY_ADDRESS] = std::vector<unsigned char>(1,111);
         base58Prefixes[SCRIPT_ADDRESS] = std::vector<unsigned char>(1,196);
+        base58Prefixes[BLINDED_ADDRESS]= std::vector<unsigned char>(1,27);
         base58Prefixes[SECRET_KEY] =     std::vector<unsigned char>(1,239);
         base58Prefixes[EXT_PUBLIC_KEY] = boost::assign::list_of(0x04)(0x35)(0x87)(0xCF).convert_to_container<std::vector<unsigned char> >();
         base58Prefixes[EXT_SECRET_KEY] = boost::assign::list_of(0x04)(0x35)(0x83)(0x94).convert_to_container<std::vector<unsigned char> >();
diff --git a/src/chainparams.h b/src/chainparams.h
index bc09bf04f6..479314a3c8 100644
--- a/src/chainparams.h
+++ b/src/chainparams.h
@@ -46,6 +46,7 @@ public:
     enum Base58Type {
         PUBKEY_ADDRESS,
         SCRIPT_ADDRESS,
+        BLINDED_ADDRESS,
         SECRET_KEY,
         EXT_PUBLIC_KEY,
         EXT_SECRET_KEY,