diff --git a/latest/fund_p2sh_p2wpkh.js b/latest/fund_p2sh_p2wpkh.js
new file mode 100644
index 0000000..d252aa6
--- /dev/null
+++ b/latest/fund_p2sh_p2wpkh.js
@@ -0,0 +1,26 @@
+var bitcoin = require('../src/index.js')
+var bscript = bitcoin.script
+var crypto = bitcoin.crypto
+var networks = bitcoin.networks
+var TransactionBuilder = bitcoin.TransactionBuilder
+
+var network = networks.testnet
+var entropy = new Buffer('14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac')
+var root = bitcoin.HDNode.fromSeedBuffer(entropy, network)
+var address = root.keyPair.getAddress()
+var wif = root.keyPair.toWIF()
+console.log(address)
+console.log(wif)
+
+var txid = '06fc7b675a31bfe3f05dab40d0cd8c044a9b2e890c696a53449d970a4adc6d52'
+var vout = 0
+var p2shScript = bscript.witnessPubKeyHash.output.encode(crypto.hash160(root.keyPair.getPublicKeyBuffer()))
+var scriptPubKey = bscript.scriptHash.output.encode(crypto.hash160(p2shScript))
+var amount = 22000
+
+var txb = new TransactionBuilder(network)
+txb.addInput(txid, vout, 0xffffffff)
+txb.addOutput(scriptPubKey, amount - 5000)
+txb.sign(0, root.keyPair)
+var tx = txb.build()
+console.log(tx.toBuffer().toString('hex'))
diff --git a/latest/fund_p2sh_p2wsh.js b/latest/fund_p2sh_p2wsh.js
new file mode 100644
index 0000000..39a2822
--- /dev/null
+++ b/latest/fund_p2sh_p2wsh.js
@@ -0,0 +1,29 @@
+var bitcoin = require('../src/index.js')
+var bscript = bitcoin.script
+var crypto = bitcoin.crypto
+var networks = bitcoin.networks
+var TransactionBuilder = bitcoin.TransactionBuilder
+
+var network = networks.testnet
+var entropy = new Buffer('14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac')
+var root = bitcoin.HDNode.fromSeedBuffer(entropy, network)
+
+var pubkeyhash = crypto.hash160(root.keyPair.getPublicKeyBuffer())
+
+var txid = 'beb647db98bda750f8202e6bc3441781ea5cfc6e3630c9d0ae47b0bfb111c249'
+var vout = 1
+var txOut = {
+  script: bscript.pubKeyHash.output.encode(pubkeyhash),
+  value: 100000
+}
+
+var witnessScript = txOut.script
+var p2shScript = bscript.witnessScriptHash.output.encode(crypto.sha256(witnessScript))
+var scriptPubKey = bscript.scriptHash.output.encode(crypto.hash160(p2shScript))
+
+var txb = new TransactionBuilder(network)
+txb.addInput(txid, vout, 0xffffffff, txOut.script)
+txb.addOutput(scriptPubKey, txOut.value - 10000)
+txb.sign(0, root.keyPair)
+var tx = txb.build()
+console.log(tx.toBuffer().toString('hex'))
diff --git a/latest/fund_p2sh_p2wsh_multisig.js b/latest/fund_p2sh_p2wsh_multisig.js
new file mode 100644
index 0000000..4a232a6
--- /dev/null
+++ b/latest/fund_p2sh_p2wsh_multisig.js
@@ -0,0 +1,32 @@
+var bitcoin = require('../src/index.js')
+var bscript = bitcoin.script
+var crypto = bitcoin.crypto
+var networks = bitcoin.networks
+var TransactionBuilder = bitcoin.TransactionBuilder
+
+var network = networks.testnet
+var entropy = new Buffer('14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac')
+var root = bitcoin.HDNode.fromSeedBuffer(entropy, network)
+var root2 = root.derive(1)
+
+var pubkeyhash = crypto.hash160(root.keyPair.getPublicKeyBuffer())
+
+var txid = 'aed14f8e918c6e7cc9347391b790f765030b07e6985fbb146bf3f6b25ddc0043'
+var vout = 0
+var txOut = {
+  script: bscript.pubKeyHash.output.encode(pubkeyhash),
+  value: 22000
+}
+
+var multisig = bscript.multisig.output.encode(2, [root.getPublicKeyBuffer(), root2.getPublicKeyBuffer()])
+var p2shScript = bscript.witnessScriptHash.output.encode(crypto.sha256(multisig))
+var scriptPubKey = bscript.scriptHash.output.encode(crypto.hash160(p2shScript))
+
+var txb = new TransactionBuilder(network)
+txb.addInput(txid, vout, 0xffffffff, txOut.script)
+txb.addOutput(scriptPubKey, txOut.value - 5000)
+txb.sign(0, root.keyPair)
+var tx = txb.build()
+console.log(tx.toBuffer().toString('hex'))
+
+// b5e7c1d911b078c754770fc372bc92096ce2605ac6b785f91ec7df0a5034ec69
diff --git a/latest/fund_p2wpkh.js b/latest/fund_p2wpkh.js
new file mode 100644
index 0000000..d26f39b
--- /dev/null
+++ b/latest/fund_p2wpkh.js
@@ -0,0 +1,29 @@
+var bitcoin = require('../src/index.js')
+var bscript = bitcoin.script
+var crypto = bitcoin.crypto
+var networks = bitcoin.networks
+var TransactionBuilder = bitcoin.TransactionBuilder
+
+var network = networks.testnet
+var entropy = new Buffer('14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac')
+var root = bitcoin.HDNode.fromSeedBuffer(entropy, network)
+var address = root.keyPair.getAddress()
+var wif = root.keyPair.toWIF()
+console.log(address)
+console.log(wif)
+
+var pubkeyhash = crypto.hash160(root.keyPair.getPublicKeyBuffer())
+
+var txid = '9aa8d1a1c5df0afccf76e84df1029062b65a98dad68e13cc765aef88ab378dd0'
+var vout = 0
+var scriptPubKey = bscript.pubKeyHash.output.encode(pubkeyhash)
+var amount = 22000
+
+var toSegwitPubkey = bscript.witnessPubKeyHash.output.encode(pubkeyhash)
+
+var txb = new TransactionBuilder(network)
+txb.addInput(txid, vout, 0xffffffff, scriptPubKey)
+txb.addOutput(toSegwitPubkey, amount - 5000)
+txb.sign(0, root.keyPair)
+var tx = txb.build()
+console.log(tx.toBuffer().toString('hex'))
diff --git a/latest/fund_p2wsh.js b/latest/fund_p2wsh.js
new file mode 100644
index 0000000..d5820fa
--- /dev/null
+++ b/latest/fund_p2wsh.js
@@ -0,0 +1,26 @@
+var bitcoin = require('../src/index.js')
+var bscript = bitcoin.script
+var crypto = bitcoin.crypto
+var networks = bitcoin.networks
+var TransactionBuilder = bitcoin.TransactionBuilder
+
+var network = networks.testnet
+var entropy = new Buffer('14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac')
+var root = bitcoin.HDNode.fromSeedBuffer(entropy, network)
+console.log(root.getAddress())
+var pubkeyhash = crypto.hash160(root.keyPair.getPublicKeyBuffer())
+
+var txid = '79f560d078eacf4cf9381544b15c400773fddd6bbfb1064956e0c345d39be260'
+var vout = 0
+var scriptPubKey = bscript.pubKeyHash.output.encode(pubkeyhash)
+var amount = 70000
+
+var witnessScriptHash = crypto.sha256(scriptPubKey)
+var toP2WSH = bscript.witnessScriptHash.output.encode(witnessScriptHash)
+
+var txb = new TransactionBuilder(network)
+txb.addInput(txid, vout, 0xffffffff, scriptPubKey)
+txb.addOutput(toP2WSH, amount - 5000)
+txb.sign(0, root.keyPair)
+var tx = txb.build()
+console.log(tx.toBuffer().toString('hex'))
diff --git a/latest/spend_p2sh_p2wpkh.js b/latest/spend_p2sh_p2wpkh.js
new file mode 100644
index 0000000..13e9799
--- /dev/null
+++ b/latest/spend_p2sh_p2wpkh.js
@@ -0,0 +1,46 @@
+var bitcoin = require('../src/index.js')
+
+var bscript = bitcoin.script
+var crypto = bitcoin.crypto
+var networks = bitcoin.networks
+// var baddress = bitcoin.address
+var TransactionBuilder = bitcoin.TransactionBuilder
+var TxSigner = bitcoin.TxSigner
+var network = networks.testnet
+
+var entropy = new Buffer('14bdfeac14bdfeac14bdfeac1100feac14bdfeac14bdfeac14bdfeac14bdfeac') // my entropy
+var root = bitcoin.HDNode.fromSeedBuffer(entropy, network)
+
+var pubkeyhash = crypto.hash160(root.keyPair.getPublicKeyBuffer())
+// redeem script
+var toSegwitPubkey = bscript.witnessPubKeyHash.output.encode(pubkeyhash)
+// aixo es l-envoltori del p2sh crec
+var p2sh = bscript.scriptHash.output.encode(crypto.hash160(toSegwitPubkey))
+// on hem rebut la pasta inicial
+// var receiveAddress = baddress.toBase58Check(crypto.hash160(toSegwitPubkey), network.scriptHash)
+
+// txhash de la tx que estem gastant
+var txhashUnspent = 'b085099291d44edecfb3a98384f4266282964fe7b0a12d6db9169698cb7e6487'
+var vout = 0
+// on gastarem la pasta despres
+
+var myaddress = '2N6stcWuMpLgt4nkiaEFXP6p9J9VKRHCwDJ'
+
+var txOut = {
+  script: p2sh,
+  value: 30000
+}
+
+var txb = new TransactionBuilder(network)
+txb.addInput(txhashUnspent, vout, 0xffffffff, p2sh)
+txb.addOutput(myaddress, txOut.value - 5000)
+
+var unsigned = txb.buildIncomplete()
+var signer = new TxSigner(unsigned)
+signer.sign(0, root.keyPair, {
+  scriptPubKey: txOut.script,
+  redeemScript: toSegwitPubkey,
+  value: txOut.value
+})
+var txd = signer.done()
+console.log(txd.toBufferWithWitness().toString('hex'))
diff --git a/latest/spend_p2sh_p2wsh.js b/latest/spend_p2sh_p2wsh.js
new file mode 100644
index 0000000..069d008
--- /dev/null
+++ b/latest/spend_p2sh_p2wsh.js
@@ -0,0 +1,39 @@
+var bitcoin = require('../src/index.js')
+
+var bscript = bitcoin.script
+var crypto = bitcoin.crypto
+var networks = bitcoin.networks
+var TransactionBuilder = bitcoin.TransactionBuilder
+var TxSigner = bitcoin.TxSigner
+
+var network = networks.testnet
+var entropy = new Buffer('14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac')
+var root = bitcoin.HDNode.fromSeedBuffer(entropy, network)
+
+var pubkeyhash = crypto.hash160(root.keyPair.getPublicKeyBuffer())
+var witnessScript = bscript.pubKeyHash.output.encode(pubkeyhash)
+var p2shScript = bscript.witnessScriptHash.output.encode(crypto.sha256(witnessScript))
+var scriptPubKey = bscript.scriptHash.output.encode(crypto.hash160(p2shScript))
+
+var txid = '2f789c63bb88c0ca844cf9ab5c59e1d6e935fa9ae6d6b5bc2c5251fca549f09d'
+var vout = 0
+var txOut = {
+  script: scriptPubKey,
+  value: 90000
+}
+
+var builder = new TransactionBuilder(network)
+builder.addInput(txid, vout, 0xffffffff, txOut.script)
+builder.addOutput('2N6stcWuMpLgt4nkiaEFXP6p9J9VKRHCwDJ', 10000)
+
+var unsigned = builder.buildIncomplete()
+var signer = new TxSigner(unsigned)
+signer.sign(0, root.keyPair, {
+  scriptPubKey: txOut.scriptPubKey,
+  redeemScript: p2shScript,
+  witnessScript: witnessScript,
+  value: txOut.value
+})
+
+var txd = signer.done()
+console.log(txd.toBuffer().toString('hex'))
diff --git a/latest/spend_p2sh_p2wsh_multisig.js b/latest/spend_p2sh_p2wsh_multisig.js
new file mode 100644
index 0000000..1e6de0e
--- /dev/null
+++ b/latest/spend_p2sh_p2wsh_multisig.js
@@ -0,0 +1,47 @@
+var bitcoin = require('../src/index.js')
+var bscript = bitcoin.script
+var crypto = bitcoin.crypto
+var networks = bitcoin.networks
+var TransactionBuilder = bitcoin.TransactionBuilder
+var TxSigner = bitcoin.TxSigner
+
+var network = networks.testnet
+var entropy = new Buffer('14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac')
+var root = bitcoin.HDNode.fromSeedBuffer(entropy, network)
+var root2 = root.derive(1)
+
+// var address = root.keyPair.getAddress()
+// var wif = root.keyPair.toWIF()
+// console.log(address)
+// console.log(wif)
+
+var multisig = bscript.multisig.output.encode(2, [root.getPublicKeyBuffer(), root2.getPublicKeyBuffer()])
+var p2shScript = bscript.witnessScriptHash.output.encode(crypto.sha256(multisig))
+var scriptPubKey = bscript.scriptHash.output.encode(crypto.hash160(p2shScript))
+
+var txid = '5d614b47c75ca29a16086e7866de7522e59a09491bbd7e914923f5aabc62616a'
+var vout = 0
+var txOut = {
+  script: scriptPubKey,
+  value: 15000
+}
+
+var builder = new TransactionBuilder(network)
+builder.addInput(txid, vout, 0xffffffff, txOut.script)
+builder.addOutput('2N6stcWuMpLgt4nkiaEFXP6p9J9VKRHCwDJ', 10000)
+
+var unsigned = builder.buildIncomplete()
+var signer = new TxSigner(unsigned)
+
+var data = {
+  scriptPubKey: txOut.script,
+  value: txOut.value,
+  redeemScript: p2shScript,
+  witnessScript: multisig
+}
+
+signer.sign(0, root.keyPair, data)
+signer.sign(0, root2.keyPair, data)
+
+var txd = signer.done()
+console.log(txd.toBuffer().toString('hex'))
diff --git a/latest/spend_p2wpkh.js b/latest/spend_p2wpkh.js
new file mode 100644
index 0000000..16d4f58
--- /dev/null
+++ b/latest/spend_p2wpkh.js
@@ -0,0 +1,38 @@
+var bitcoin = require('../src/index.js')
+var bscript = bitcoin.script
+var crypto = bitcoin.crypto
+var networks = bitcoin.networks
+var TransactionBuilder = bitcoin.TransactionBuilder
+var TxSigner = bitcoin.TxSigner
+
+var network = networks.testnet
+var entropy = new Buffer('14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac')
+var root = bitcoin.HDNode.fromSeedBuffer(entropy, network)
+var address = root.keyPair.getAddress()
+var wif = root.keyPair.toWIF()
+console.log(address)
+console.log(wif)
+
+var pubkeyhash = crypto.hash160(root.keyPair.getPublicKeyBuffer())
+var txid = 'cca0f194d0ca770737121532497f82b3b4eb861df462bbb26978e53acfec7de8'
+var vout = 0
+
+var txOut = {
+  script: bscript.witnessPubKeyHash.output.encode(pubkeyhash),
+  value: 17000
+}
+
+var builder = new TransactionBuilder(network)
+builder.addInput(txid, vout, 0xffffffff, txOut.script)
+builder.addOutput('2N6stcWuMpLgt4nkiaEFXP6p9J9VKRHCwDJ', txOut.value - 5000)
+
+var unsigned = builder.buildIncomplete()
+var signer = new TxSigner(unsigned)
+signer.sign(0, root.keyPair, {
+  scriptPubKey: txOut.script,
+  value: txOut.value
+})
+
+var txd = signer.done()
+
+console.log(txd.toBuffer().toString('hex'))
diff --git a/latest/spend_p2wsh.js b/latest/spend_p2wsh.js
new file mode 100644
index 0000000..d9c2afd
--- /dev/null
+++ b/latest/spend_p2wsh.js
@@ -0,0 +1,42 @@
+var bitcoin = require('../src/index.js')
+var bscript = bitcoin.script
+var crypto = bitcoin.crypto
+var networks = bitcoin.networks
+var TransactionBuilder = bitcoin.TransactionBuilder
+var TxSigner = bitcoin.TxSigner
+
+var network = networks.testnet
+var entropy = new Buffer('14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac14bdfeac')
+var root = bitcoin.HDNode.fromSeedBuffer(entropy, network)
+// var address = root.keyPair.getAddress()
+// var wif = root.keyPair.toWIF()
+// console.log(address)
+// console.log(wif)
+
+var pubkeyhash = crypto.hash160(root.keyPair.getPublicKeyBuffer())
+var witnessScript = bscript.pubKeyHash.output.encode(pubkeyhash)
+var scriptHash = crypto.sha256(witnessScript)
+var scriptPubKey = bscript.witnessScriptHash.output.encode(scriptHash)
+var txid = '6d1c2682f553889e3887762fcf4669ab3844c6803d6c5c366bc2909bbe33cbf9'
+var vout = 0
+
+var txOut = {
+  script: scriptPubKey,
+  value: 65000
+}
+
+var builder = new TransactionBuilder(network)
+builder.addInput(txid, vout, 0xffffffff, txOut.script)
+builder.addOutput('2N6stcWuMpLgt4nkiaEFXP6p9J9VKRHCwDJ', 10000)
+
+var unsigned = builder.buildIncomplete()
+var signer = new TxSigner(unsigned)
+signer.sign(0, root.keyPair, {
+  scriptPubKey: scriptPubKey,
+  witnessScript: witnessScript,
+  value: txOut.value
+})
+
+var txd = signer.done()
+console.log(txd.toBuffer().toString('hex'))
+
diff --git a/src/index.js b/src/index.js
index 25b3da5..a03687b 100644
--- a/src/index.js
+++ b/src/index.js
@@ -5,7 +5,7 @@ module.exports = {
   HDNode: require('./hdnode'),
   Transaction: require('./transaction'),
   TransactionBuilder: require('./transaction_builder'),
-
+  TxSigner: require('./transaction_signer'),
   address: require('./address'),
   bufferutils: require('./bufferutils'),
   crypto: require('./crypto'),
diff --git a/src/transaction.js b/src/transaction.js
index 2e9f028..33424c6 100644
--- a/src/transaction.js
+++ b/src/transaction.js
@@ -34,7 +34,8 @@ Transaction.SIGHASH_SINGLE = 0x03
 Transaction.SIGHASH_ANYONECANPAY = 0x80
 Transaction.ADVANCED_TRANSACTION_MARKER = 0x00
 Transaction.ADVANCED_TRANSACTION_FLAG = 0x01
-
+Transaction.SIG_V0 = 0
+Transaction.SIG_V1 = 1
 var EMPTY_SCRIPT = new Buffer(0)
 var EMPTY_WITNESS = []
 var ZERO = new Buffer('0000000000000000000000000000000000000000000000000000000000000000', 'hex')
diff --git a/src/transaction_signer.js b/src/transaction_signer.js
new file mode 100644
index 0000000..122d0b4
--- /dev/null
+++ b/src/transaction_signer.js
@@ -0,0 +1,516 @@
+var bscript = require('./script')
+var OPS = require('./opcodes.json')
+var bscriptNumber = require('./script_number')
+var bcrypto = require('./crypto')
+var bufferEquals = require('buffer-equals')
+var typeforce = require('typeforce')
+var types = require('./types')
+var ECPair = require('./ecpair')
+var ECSignature = require('./ecsignature')
+var Transaction = require('./transaction')
+var EMPTY_SCRIPT = new Buffer(0)
+var SIGNABLE_SCRIPTS = [
+  bscript.types.MULTISIG,
+  bscript.types.P2PKH,
+  bscript.types.P2PK
+]
+
+var ALLOWED_P2SH_SCRIPTS = [
+  bscript.types.MULTISIG,
+  bscript.types.P2PKH,
+  bscript.types.P2PK,
+  bscript.types.P2WSH,
+  bscript.types.P2WPKH
+]
+
+function calculateSigHash (tx, nIn, scriptCode, sigHashType, sigVersion, txOutAmount) {
+  return sigVersion === 1
+    ? tx.hashForWitnessV0(nIn, scriptCode, txOutAmount, sigHashType)
+    : tx.hashForSignature(nIn, scriptCode, sigHashType)
+}
+
+function sortMultisigs (tx, nIn, txOutValue, ecsigs, publicKeys, scriptCode, sigVersion) {
+  var results = []
+  var hash
+  var ikey = 0
+  var isig = 0
+  var sig, key
+  var success = true
+  var sigsCount = ecsigs.length
+  var keysCount = publicKeys.length
+  while (success && ecsigs.length > 0) {
+    sig = ECSignature.parseScriptSignature(ecsigs[isig])
+    key = ECPair.fromPublicKeyBuffer(publicKeys[ikey])
+    hash = calculateSigHash(tx, nIn, scriptCode, sig.hashType, sigVersion, txOutValue)
+    if (key.verify(hash, sig.signature)) {
+      isig++
+      results[key.getPublicKeyBuffer().toString('binary')] = ecsigs[isig]
+    }
+    ikey++
+    if (sigsCount > keysCount) {
+      success = false
+    }
+  }
+
+  return results
+}
+
+function calculateSignature (tx, nIn, key, scriptCode, sigHashType, sigVersion, txOutValue) {
+  var hash = calculateSigHash(tx, nIn, scriptCode, sigHashType, sigVersion, txOutValue)
+  return key.sign(hash).toScriptSignature(sigHashType)
+}
+
+function pushOnlyRead (op) {
+  if (op === OPS.OP_0) {
+    return new Buffer()
+  } else if (op instanceof Buffer) {
+    return op
+  } else if (op === OPS.OP_1NEGATE || op >= OPS.OP_1 && op <= OPS.OP_16) {
+    return bscriptNumber.encode(op - 0x50)
+  } else {
+    throw new Error('Should only be run on a push-only script')
+  }
+}
+
+function pushOnlyWrite (buffer) {
+  if (!(buffer instanceof Buffer)) {
+    throw new Error('Non-buffer passed to pushOnlyWrite')
+  }
+
+  if (buffer.length === 0) {
+    return OPS.OP_0
+  } else if (buffer.length === 1 && (buffer[0] === 0x81 || buffer[0] >= 1 && buffer[0] <= 16)) {
+    return bscriptNumber.decode(buffer)
+  } else {
+    return buffer
+  }
+}
+
+function evalPushOnly (script) {
+  return bscript.decompile(script).map(pushOnlyRead)
+}
+
+function pushAll (chunks) {
+  return bscript.compile(chunks.map(pushOnlyWrite))
+}
+
+function solveScript (scriptCode) {
+  if (!(scriptCode instanceof Buffer)) {
+    throw new Error('Argument 0 for solveScript must be a Buffer')
+  }
+
+  var outputType = bscript.classifyOutput(scriptCode)
+  var canSign = SIGNABLE_SCRIPTS.indexOf(outputType) !== -1
+  var solvedBy = null
+  var requiredSigs = null
+
+  switch (outputType) {
+    // We can only determine the relevant hash from these, not if it's signable
+    case bscript.types.P2SH:
+      solvedBy = bscript.scriptHash.output.decode(scriptCode)
+      break
+    case bscript.types.P2WSH:
+      solvedBy = bscript.witnessScriptHash.output.decode(scriptCode)
+      break
+
+    // We can immediately solve signatures for these
+    // When adding a new script type, edit here
+    case bscript.types.P2WPKH:
+      requiredSigs = 1
+      solvedBy = bscript.witnessPubKeyHash.output.decode(scriptCode)
+      break
+    case bscript.types.P2PK:
+      requiredSigs = 1
+      solvedBy = bscript.pubKey.output.decode(scriptCode)
+      break
+    case bscript.types.P2PKH:
+      requiredSigs = 1
+      solvedBy = bscript.pubKeyHash.output.decode(scriptCode)
+      break
+    case bscript.types.MULTISIG:
+      solvedBy = bscript.multisig.output.decode(scriptCode)
+      requiredSigs = solvedBy.m
+      break
+  }
+
+  return {
+    type: outputType,
+    script: scriptCode,
+    canSign: canSign,
+    solvedBy: solvedBy,
+    requiredSigs: requiredSigs
+  }
+}
+
+/**
+ * Design goals
+ *
+ *  - tolerate arbitrary sigHashType's on signatures
+ *  - given tx, nIn, txOut, we can reliably check a redeemScript and eventual witnessScript at signing
+ *  - reliably extract signatures from a signed input
+ *  - create, and re-serialize given minimal state
+ *  - clear separation of 'standard scripts' and the various script-hash scripts
+ *
+ * @param tx - the transaction we want to sign
+ * @param nIn - the input we will sign here
+ * @param opts
+ */
+function InSigner (tx, nIn, opts) {
+  if ((tx instanceof Transaction) === false) {
+    throw new Error('A transaction is required for InSigner')
+  }
+  if (opts.scriptPubKey === undefined) {
+    throw new Error('A value for scriptPubKey is required')
+  }
+
+  this.tx = tx
+  this.nIn = nIn
+  this.publicKeys = []
+  this.signatures = []
+  this.requiredSigs = null
+  this.solve(opts)
+  this.extractSig()
+}
+
+InSigner.prototype.isFullySigned = function () {
+  return this.requiredSigs !== null && this.requiredSigs === this.signatures.length
+}
+
+InSigner.prototype.extractStandard = function (solution, chunks, sigVersion) {
+  var signatures = []
+  var publicKeys = []
+  var decoded
+
+  // only SIGNABLE_SCRIPTS can be extracted here
+  if (solution.type === bscript.types.P2PK) {
+    if (bscript.pubKey.input.check(chunks)) {
+      decoded = bscript.pubKey.input.decode(chunks)
+      signatures[0] = decoded.signature
+      publicKeys[0] = solution.solvedBy
+    }
+  } else if (solution.type === bscript.types.P2PKH) {
+    if (bscript.pubKeyHash.input.check(chunks)) {
+      decoded = bscript.pubKeyHash.input.decode(chunks)
+      signatures[0] = decoded.signature
+      publicKeys[0] = decoded.pubKey
+    }
+  } else if (solution.type === bscript.types.MULTISIG) {
+    if (bscript.multisig.input.check(chunks)) {
+      publicKeys = solution.solvedBy.publicKeys
+      signatures = bscript.multisig.input.decode(chunks, true)
+
+      // We need to map signature to the pubkey index in order to re-serialize
+      var sigs = sortMultisigs(this.tx, this.nIn, this.txOut.value, signatures, publicKeys, solution.script, sigVersion)
+      for (var i = 0, l = publicKeys.length; i < l; i++) {
+        var str = publicKeys[ i ].getPublicKeyBuffer().toString('binary')
+        if (sigs[ str ] !== undefined && bscript.isCanonicalSignature(sigs[str])) {
+          signatures[ i ] = sigs[ str ]
+        }
+      }
+    }
+  } else {
+    throw new Error('Never call extractStandardFromChunks on a non-SIGNABLE script')
+  }
+
+  return [signatures, publicKeys]
+}
+
+InSigner.prototype.solve = function (opts) {
+  var solution = solveScript(opts.scriptPubKey)
+  if (solution.type === bscript.types.NONSTANDARD) {
+    throw new Error('txOut script is non-standard')
+  }
+
+  this.scriptPubKey = solution
+  if (solution.type === bscript.types.P2SH) {
+    var scriptHash = solution.solvedBy
+    if (!(opts.redeemScript instanceof Buffer)) {
+      throw new Error('Redeem script required to solve utxo')
+    }
+
+    if (!scriptHash.equals(bcrypto.hash160(opts.redeemScript))) {
+      throw new Error('Redeem script does not match txOut script hash')
+    }
+
+    solution = solveScript(opts.redeemScript)
+    if (ALLOWED_P2SH_SCRIPTS.indexOf(solution.type)) {
+      this.redeemScript = solution
+    } else {
+      throw new Error('Unsupported P2SH script')
+    }
+  }
+
+  if (solution.type === bscript.types.P2WPKH) {
+    if (!types.Satoshi(opts.value)) {
+      throw new Error('Value is required for witness-key-hash')
+    }
+    this.value = opts.value
+  } else if (solution.type === bscript.types.P2WSH) {
+    var witnessScriptHash = solution.solvedBy
+    if (!(opts.witnessScript instanceof Buffer)) {
+      throw new Error('P2WSH script required to solve utxo')
+    }
+    if (!types.Satoshi(opts.value)) {
+      throw new Error('Value is required for witness-script-hash')
+    }
+    if (!bufferEquals(bcrypto.sha256(opts.witnessScript), witnessScriptHash)) {
+      throw new Error('Witness script does not match txOut script hash')
+    }
+    this.witnessScript = solveScript(opts.witnessScript)
+    this.value = opts.value
+    if (SIGNABLE_SCRIPTS.indexOf(this.witnessScript.type) === -1) {
+      throw new Error('witness script is not supported')
+    }
+  }
+}
+
+InSigner.prototype.extractSig = function () {
+  // Attempt decoding of the input scriptSig and witness
+  var input = this.tx.ins[this.nIn]
+  var solution = this.scriptPubKey
+  if (solution.canSign) {
+    [this.signatures, this.publicKeys] = this.extractStandard(solution, evalPushOnly(input.script), Transaction.SIG_V0)
+  }
+
+  if (solution.type === bscript.types.P2SH) {
+    if (bscript.scriptHash.input.check(input.script)) {
+      var p2sh = bscript.scriptHash.input.decode(input.script)
+      if (!p2sh.redeemScript.equals(this.redeemScript.script)) {
+        throw new Error('Redeem script from scriptSig does not match')
+      }
+      if (this.redeemScript.canSign) {
+        [this.signatures, this.publicKeys] = this.extractStandard(solution, evalPushOnly(p2sh.redeemScriptSig), Transaction.SIG_V0)
+      }
+      solution = this.redeemScript
+    }
+  }
+
+  if (solution.type === bscript.types.P2WPKH) {
+    if (input.witness.length === 2) {
+      var witnessKeyHash = solution.solvedBy
+      if (!witnessKeyHash.equals(bcrypto.hash160(input.witness[1]))) {
+        throw new Error('Public key does not match key-hash')
+      }
+
+      [this.signatures, this.publicKeys] = this.extractStandard(bscript.types.P2PKH, input.witness)
+    }
+  } else if (solution.type === bscript.types.P2WSH) {
+    if (input.witness.length > 0) {
+      if (!this.witnessScript.equals(input.witness[ input.witness.length - 1 ])) {
+        throw new Error('Witness script does not match')
+      }
+
+      if (this.witnessScript.canSign) {
+        [ this.signatures, this.publicKeys ] = this.extractStandard(solution, input.witness.slice(0, -1), Transaction.SIG_V1)
+      }
+    }
+  }
+}
+
+function signStandard (tx, nIn, txOutValue, signatures, publicKeys, key, solution, sigHashType, sigVersion) {
+  // Only SIGNABLE_SCRIPTS can be signed here
+  var didSign = false
+  var keyBuffer = key.getPublicKeyBuffer()
+  if (solution.type === bscript.types.P2PK) {
+    if (bufferEquals(keyBuffer, solution.solvedBy)) {
+      signatures = [calculateSignature(tx, nIn, key, solution.script, sigHashType, sigVersion, txOutValue)]
+      publicKeys = [keyBuffer]
+      didSign = true
+    }
+  } else if (solution.type === bscript.types.P2PKH) {
+    if (bufferEquals(bcrypto.hash160(keyBuffer), solution.solvedBy)) {
+      signatures = [calculateSignature(tx, nIn, key, solution.script, sigHashType, sigVersion, txOutValue)]
+      publicKeys = [keyBuffer]
+      didSign = true
+    }
+  } else if (solution.type === bscript.types.MULTISIG) {
+    for (var i = 0, keyLen = solution.solvedBy.pubKeys.length; i < keyLen; i++) {
+      publicKeys[i] = solution.solvedBy.pubKeys[i]
+      if (bufferEquals(keyBuffer, publicKeys[i])) {
+        didSign = true
+        signatures[i] = calculateSignature(tx, nIn, key, solution.script, sigHashType, sigVersion, txOutValue)
+      }
+    }
+  } else {
+    throw new Error('signStandard can only sign SIGNABLE_SCRIPTS')
+  }
+
+  if (!didSign) {
+    throw new Error('Signing input with wrong private key')
+  }
+
+  return [signatures, publicKeys]
+}
+
+InSigner.prototype.sign = function (key, sigHashType) {
+  sigHashType = sigHashType || Transaction.SIGHASH_ALL
+
+  // Attempt to solve the txOut script
+  var solution = this.scriptPubKey
+  if (solution.canSign) {
+    [this.signatures, this.publicKeys] = signStandard(this.tx, this.nIn, undefined, this.signatures, this.publicKeys, key, solution, sigHashType, Transaction.SIG_V0)
+  }
+
+  // If the spkPubKeyHash was solvable, and the type is P2SH, we try again with the redeemScript
+  if (solution.type === bscript.types.P2SH) {
+    // solution updated, type is the type of the redeemScript
+    solution = this.redeemScript
+    if (bscript.P2SH_SCRIPTS.indexOf(solution.type)) {
+      if (solution.canSign) {
+        [this.signatures, this.publicKeys] = signStandard(this.tx, this.nIn, undefined, this.signatures, this.publicKeys, key, solution, sigHashType, Transaction.SIG_V0)
+      }
+    }
+  }
+
+  if (solution.type === bscript.types.P2WPKH) {
+    var p2wpkh = solveScript(bscript.pubKeyHash.output.encode(solution.solvedBy));
+    [this.signatures, this.publicKeys] = signStandard(this.tx, this.nIn, this.value, this.signatures, this.publicKeys, key, p2wpkh, sigHashType, Transaction.SIG_V1)
+  } else if (solution.type === bscript.types.P2WSH) {
+    solution = this.witnessScript
+    if (solution.canSign) {
+      [this.signatures, this.publicKeys] = signStandard(this.tx, this.nIn, this.value, this.signatures, this.publicKeys, key, solution, sigHashType, Transaction.SIG_V1)
+    }
+  }
+
+  this.requiredSigs = this.publicKeys.length
+
+  return solution
+}
+
+function serializeStandard (outputType, signatures, publicKeys) {
+  // When adding a new script type, edit here
+  var chunks = []
+  switch (outputType) {
+    case bscript.types.P2PK:
+      if (signatures.length === 1) {
+        chunks = [signatures[ 0 ]]
+      }
+      break
+    case bscript.types.P2PKH:
+      if (signatures.length === 1) {
+        chunks = [signatures[ 0 ], publicKeys[ 0 ]]
+      }
+      break
+    case bscript.types.MULTISIG:
+      chunks.push(new Buffer(0))
+      chunks = chunks.concat(signatures.map(function (signature) {
+        if (signature instanceof Buffer === false) {
+          throw new Error('debugging probably required')
+        }
+        return signature
+      }))
+      break
+    default:
+      throw new Error('serializeStandardChunks only works with a SIGNABLE_SCRIPT')
+  }
+
+  return chunks
+}
+
+function serializeSigData (signatures, publicKeys, scriptPubKey, redeemScript, witnessScript) {
+  var sigData = {
+    scriptSig: EMPTY_SCRIPT,
+    witness: []
+  }
+  var type = scriptPubKey.type
+  if (scriptPubKey.canSign) {
+    sigData.scriptSig = pushAll(serializeStandard(type, signatures, publicKeys))
+  }
+
+  var p2sh = false
+  if (type === bscript.types.P2SH) {
+    if (redeemScript === undefined) {
+      throw new Error('Redeem script not provided')
+    }
+    p2sh = true
+    type = redeemScript.type
+    if (redeemScript.canSign) {
+      sigData.scriptSig = pushAll(serializeStandard(type, signatures, publicKeys))
+    }
+  }
+
+  if (type === bscript.types.P2WPKH) {
+    sigData.witness = serializeStandard(bscript.types.P2PKH, signatures, publicKeys)
+  } else if (type === bscript.types.P2WSH) {
+    if (witnessScript === undefined) {
+      throw new Error('Witness script not provided')
+    }
+    type = witnessScript.type
+    if (witnessScript.canSign) {
+      sigData.scriptSig = EMPTY_SCRIPT
+      sigData.witness = serializeStandard(type, signatures, publicKeys)
+      sigData.witness.push(witnessScript.script)
+    }
+  }
+
+  if (p2sh) {
+    sigData.scriptSig = bscript.scriptHash.input.encode(sigData.scriptSig, redeemScript.script)
+  }
+
+  return sigData
+}
+
+InSigner.prototype.serializeSigData = function () {
+  return serializeSigData(this.signatures, this.publicKeys, this.scriptPubKey, this.redeemScript, this.witnessScript)
+}
+
+/**
+ * Create a TxSigner for this transaction instance
+ * @param tx
+ * @constructor
+ */
+function TxSigner (tx) {
+  if (tx === undefined || (tx instanceof Transaction) === false) {
+    throw new Error('A transaction is required for TxSigner')
+  }
+
+  this.tx = tx.clone()
+  this.states = []
+}
+
+/**
+ * Sign a transaction.
+ *
+ * @param nIn - the input to sign
+ * @param key - the private key to sign with
+ * @param sigHashType - SIGHASH type to sign with
+ * @param opts - optional data required to solve UTXO
+ */
+TxSigner.prototype.sign = function (nIn, key, opts, sigHashType) {
+  typeforce(types.Number, nIn)
+  typeforce(types.maybe(Number), sigHashType)
+  if (sigHashType === undefined) {
+    sigHashType = Transaction.SIGHASH_ALL
+  }
+  // You can probably make this work with the current library, if you can work out the witnessScript above!
+  // generate opts for the internal signer based off older way of positional arguments to TxSigner.sign
+
+  if (this.states[nIn] === undefined) {
+    this.states[nIn] = new InSigner(this.tx, nIn, opts)
+  }
+
+  if (!this.states[nIn].sign(key, sigHashType)) {
+    throw new Error('Unsignable input: ', nIn)
+  }
+
+  return true
+}
+
+/**
+ * Produce a Transaction with our changes.
+ */
+TxSigner.prototype.done = function () {
+  var tx = this.tx.clone()
+
+  var states = this.states
+  for (var i = 0, l = tx.ins.length; i < l; i++) {
+    if (this.states[i] !== undefined) {
+      var sigData = states[i].serializeSigData()
+      tx.ins[i].script = sigData.scriptSig
+      tx.ins[i].witness = sigData.witness
+    }
+  }
+  return tx
+}
+
+module.exports = TxSigner