From 7db055f1abb9371a4607efd06f0047d28283a1e6 Mon Sep 17 00:00:00 2001
From: Nadav Kohen <nadavk25@gmail.com>
Date: Fri, 13 Dec 2019 17:58:19 -0600
Subject: [PATCH] Respond to Review on Transactions.md

---
 Transactions.md | 81 ++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 63 insertions(+), 18 deletions(-)

diff --git a/Transactions.md b/Transactions.md
index cb2715e..6a72641 100644
--- a/Transactions.md
+++ b/Transactions.md
@@ -12,26 +12,26 @@
   * Total Local Collateral: `CurrencyUnit`
   * Total Remote Collateral: `CurrencyUnit`
   * Fee Rate: `FeeUnit`
-  * Output Type: `OutputType`
 
 Where
   - Local something something Remote
   - The sum of each `Funding Inputs`' value is at least that of its `Total Collateral`
   - `Funding Public Key`s are both 33-byte compressed public keys
-  - `nLockTime` is in the past
-  - `Output Type` is one of `Raw`, `P2SH`, `P2WSH`, or `P2SH-P2WSH`
+  - `nLockTime` is in the past (rather than just using 0)
+    - for privacy purposes and also to prevent [fee snipping](https://github.com/zkSNACKs/WalletWasabi/issues/2500)
+  - Both `Change ScriptPubKey`s must be either `P2WSH/P2WPKH`, or `P2SH-P2WSH/P2SH-P2WPKH`
 ### <a name="FundingGlobal">Global</a>
   * nLockTime
 ### <a name="FundingInputs">Inputs</a>
   * Local Funding Inputs
   * Remote Funding Inputs
 ### <a name="FundingOutputs">Outputs</a>
-  * Output Type(DLC Funding Output)
+  * P2WSH(DLC Funding Output)
   * Local Change ScriptPubKey
   * Remote Change ScriptPubKey
 
 Where
-  - `Output Type(DLC Funding Output)`'s value is `Total Local Collateral + Total Remote Collateral`
+  - `P2WSH(DLC Funding Output)`'s value is `Total Local Collateral + Total Remote Collateral`
   - `DLC Funding Output`'s script is
    
         OP_2 <Local Funding Public Key> <Remote Funding Public Key> OP_2 OP_CHECKMULTISIG
@@ -49,25 +49,24 @@ Where
   * Timeout: `UInt32`
   * DLC Funding Output: `ScriptPubKey`
   * Fee Rate: `FeeUnit`
-  * Output Type: `OutputType`
   
 Where
   - `Oracle Signature Point` is the 33-byte public key associated with this CET's outcome
   - Both `CET Public Key`s are 33-byte compressed public keys
   - `Local Paytout + Remote Payout = (DLC Funding Output).value`
-  - `nLockTime` is in the past
+  - `nLockTime` is in the past (rather than just using 0)
+    - for privacy purposes and also to prevent [fee snipping](https://github.com/zkSNACKs/WalletWasabi/issues/2500)
   - `DLC Funding Output` is of the form [specified above](#FundingOutputs)
-  - `Output Type` is one of `Raw`, `P2SH`, `P2WSH`, or `P2SH-P2WSH`
 ### <a name="CETGlobal">Global</a>
   * nLockTime
 ### <a name="CETInputs">Inputs</a>
-  * Input Spending(OutputType(DLC Funding Output))
+  * Input Spending(P2WSH(DLC Funding Output))
 ### <a name="CETOutputs">Outputs</a>
-  * OutputType(ToLocalOutput)
-  * OutputType(ToRemoteOutput)
+  * P2WSH(ToLocalOutput)
+  * ToRemoteOutput
   
 Where
-  - `ToLocalOutput.value = Local Payout - Local Fee`
+  - `P2WSH(ToLocalOutput).value = Local Payout - Local Fee`
   - `ToRemoteOutput.value = Remote Payout - Remote Fee`
   - `Local Fee = Remote Fee`
   - `ToLocalOutput`'s script is:
@@ -81,7 +80,9 @@ Where
         
   - `ToRemoteOutput`'s script is:
   
-        OP_DUP OP_HASH160 <Hash160(Remote CET Public Key)> OP_EQUALVERIFY OP_CHECKSIG
+        OP_0 <Hash160(Remote CET Public Key)>
+        
+    Which is `P2WPKH(Remote CET Public Key)`
   
 ## Refund Transaction
 ### <a name="RefundKnownValues">Known Values</a>
@@ -92,17 +93,15 @@ Where
   * Timeout: `UInt32`
   * DLC Funding Output: `ScriptPubKey`
   * Fee Rate: `FeeUnit`
-  * Output Type: `OutputType`
   
 Where
   - Both `Refund Public Key`s are 33-byte compressed public keys
   - `Total Local Collateral + Total Remote Collateral = (DLC Funding Output).value`
   - `DLC Funding Output` is of the form [specified above](#FundingOutputs)
-  - `Output Type` is one of `Raw`, `P2SH`, `P2WSH`, or `P2SH-P2WSH`
 ### <a name="RefundGlobal">Global</a>
   * nLockTime is `Timeout`
 ### <a name="RefundInputs">Inputs</a>
-  * Input Spending(OutputType(DLC Funding Output))
+  * Input Spending(P2WSH(DLC Funding Output))
 ### <a name="RefundOutputs">Outputs</a>
   * ToLocalOutput
   * ToRemoteOutput
@@ -113,8 +112,54 @@ Where
   - `Local Fee / Total Local Collateral = Remote Fee / Total Remote Collateral`
   - `ToLocalOutput`'s script is:
   
-        OP_DUP OP_HASH160 <Hash160(Local Refund Public Key)> OP_EQUALVERIFY OP_CHECKSIG
+        OP_0 <Hash160(Local Refund Public Key)>
+        
+    Which is `P2WPKH(Local Refund Public Key)`
   
   - `ToRemoteOutput`'s script is:
   
-        OP_DUP OP_HASH160 <Hash160(Remote Refund Public Key)> OP_EQUALVERIFY OP_CHECKSIG
+        OP_0 <Hash160(Remote Refund Public Key)>
+        
+    Which is `P2WPKH(Remote Refund Public Key)`
+
+## Closing Transaction (Unilateral)
+### <a name="ClosingKnownValues">Known Values</a>
+  * Local Unilateral Public Key: `ECPublicKey`
+  * nLockTime: `UInt32`
+  * ToLocalOutput: `ScriptPubKey`
+  * Fee Rate: `FeeUnit`
+
+Where
+  - `ToLocalOutput` is of the form [specified above](#CETOutputs)
+  - `nLockTime` is in the past (rather than just using 0)
+    - for privacy purposes and also to prevent [fee snipping](https://github.com/zkSNACKs/WalletWasabi/issues/2500)
+### <a name="ClosingGlobal">Global</a>
+  * nLockTime
+### <a name="ClosingInputs">Inputs</a>
+  * Input Spending(P2WSH(ToLocalOutput))
+### <a name="ClosingOutputs">Outputs</a>
+  * P2WPKH(Local Unilateral Public Key)
+
+Where
+  - `P2WPKH(Local Unilateral Public Key)`'s value is `P2WSH(ToLocalOutput).value - fee`
+
+## Closing Transaction (Justice)
+### <a name="ClosingKnownValues">Known Values</a>
+  * Local Justice Public Key: `ECPublicKey`
+  * nLockTime: `UInt32`
+  * Remote's ToLocalOutput: `ScriptPubKey`
+  * Fee Rate: `FeeUnit`
+  
+Where
+  - `Remote's ToLocalOutput` is of the form [specified above](#CETOutputs)
+  - `nLockTime` is in the past (rather than just using 0)
+    - for privacy purposes and also to prevent [fee snipping](https://github.com/zkSNACKs/WalletWasabi/issues/2500)
+### <a name="ClosingGlobal">Global</a>
+  * nLockTime
+### <a name="ClosingInputs">Inputs</a>
+  * Input Spending(P2WSH(Remote's ToLocalOutput))
+### <a name="ClosingOutputs">Outputs</a>
+  * P2WPKH(Local Justice Public Key)
+
+Where
+  - `P2WPKH(Local Justice Public Key)`'s value is `P2WSH(Remote's ToLocalOutput).value - fee`