From a868d2740748b8fe8c9276951739061c237038bd Mon Sep 17 00:00:00 2001
From: Daniel Cousens <github@dcousens.com>
Date: Thu, 19 Oct 2017 11:22:17 +1100
Subject: [PATCH] TxBuilder: add support for RSBuffer type keyPairs and
 .publicKey

---
 src/transaction_builder.js  | 13 +++++++++----
 test/transaction_builder.js | 13 +++++++++++++
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/src/transaction_builder.js b/src/transaction_builder.js
index e2469e4..4892e06 100644
--- a/src/transaction_builder.js
+++ b/src/transaction_builder.js
@@ -667,7 +667,8 @@ function canSign (input) {
 }
 
 TransactionBuilder.prototype.sign = function (vin, keyPair, redeemScript, hashType, witnessValue, witnessScript) {
-  if (keyPair.network !== this.network) throw new Error('Inconsistent network')
+  // TODO: remove keyPair.network matching in 4.0.0
+  if (keyPair.network && keyPair.network !== this.network) throw new TypeError('Inconsistent network')
   if (!this.inputs[vin]) throw new Error('No input at index: ' + vin)
   hashType = hashType || Transaction.SIGHASH_ALL
 
@@ -680,7 +681,7 @@ TransactionBuilder.prototype.sign = function (vin, keyPair, redeemScript, hashTy
     throw new Error('Inconsistent redeemScript')
   }
 
-  var kpPubKey = keyPair.getPublicKeyBuffer()
+  var kpPubKey = keyPair.publicKey || keyPair.getPublicKeyBuffer()
   if (!canSign(input)) {
     if (witnessValue !== undefined) {
       if (input.value !== undefined && input.value !== witnessValue) throw new Error('Input didn\'t match witnessValue')
@@ -699,14 +700,18 @@ TransactionBuilder.prototype.sign = function (vin, keyPair, redeemScript, hashTy
   } else {
     signatureHash = this.tx.hashForSignature(vin, input.signScript, hashType)
   }
+
   // enforce in order signing of public keys
   var signed = input.pubKeys.some(function (pubKey, i) {
     if (!kpPubKey.equals(pubKey)) return false
     if (input.signatures[i]) throw new Error('Signature already exists')
-    if (!keyPair.compressed &&
+    if (kpPubKey.length !== 33 &&
       input.signType === scriptTypes.P2WPKH) throw new Error('BIP143 rejects uncompressed public keys in P2WPKH or P2WSH')
 
-    input.signatures[i] = keyPair.sign(signatureHash).toScriptSignature(hashType)
+    var signature = keyPair.sign(signatureHash)
+    if (Buffer.isBuffer(signature)) signature = ECSignature.fromRSBuffer(signature)
+
+    input.signatures[i] = signature.toScriptSignature(hashType)
     return true
   })
 
diff --git a/test/transaction_builder.js b/test/transaction_builder.js
index 82dda19..bcc331e 100644
--- a/test/transaction_builder.js
+++ b/test/transaction_builder.js
@@ -294,6 +294,19 @@ describe('TransactionBuilder', function () {
   })
 
   describe('sign', function () {
+    it('supports the alternative abstract interface { publicKey, sign }', function () {
+      var keyPair = {
+        publicKey: Buffer.alloc(33, 0x03),
+        sign: function (hash) { return Buffer.alloc(64) }
+      }
+
+      var txb = new TransactionBuilder()
+      txb.addInput('ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff', 1)
+      txb.addOutput('1111111111111111111114oLvT2', 100000)
+      txb.sign(0, keyPair)
+      assert.equal(txb.build().toHex(), '0100000001ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff010000002c0930060201000201000121030303030303030303030303030303030303030303030303030303030303030303ffffffff01a0860100000000001976a914000000000000000000000000000000000000000088ac00000000')
+    })
+
     fixtures.invalid.sign.forEach(function (f) {
       it('throws on ' + f.exception + (f.description ? ' (' + f.description + ')' : ''), function () {
         var txb = construct(f, true)