diff --git a/src/bitcoin-tx.cpp b/src/bitcoin-tx.cpp
index ab0efde05..181e2bb1b 100644
--- a/src/bitcoin-tx.cpp
+++ b/src/bitcoin-tx.cpp
@@ -1,4 +1,4 @@
-// Copyright (c) 2009-2017 The Bitcoin Core developers
+// Copyright (c) 2009-2018 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -193,18 +193,18 @@ static CAmount ExtractAndValidateValue(const std::string& strValue)
 
 static void MutateTxVersion(CMutableTransaction& tx, const std::string& cmdVal)
 {
-    int64_t newVersion = atoi64(cmdVal);
-    if (newVersion < 1 || newVersion > CTransaction::MAX_STANDARD_VERSION)
-        throw std::runtime_error("Invalid TX version requested");
+    int64_t newVersion;
+    if (!ParseInt64(cmdVal, &newVersion) || newVersion < 1 || newVersion > CTransaction::MAX_STANDARD_VERSION)
+        throw std::runtime_error("Invalid TX version requested: '" + cmdVal + "'");
 
     tx.nVersion = (int) newVersion;
 }
 
 static void MutateTxLocktime(CMutableTransaction& tx, const std::string& cmdVal)
 {
-    int64_t newLocktime = atoi64(cmdVal);
-    if (newLocktime < 0LL || newLocktime > 0xffffffffLL)
-        throw std::runtime_error("Invalid TX locktime requested");
+    int64_t newLocktime;
+    if (!ParseInt64(cmdVal, &newLocktime) || newLocktime < 0LL || newLocktime > 0xffffffffLL)
+        throw std::runtime_error("Invalid TX locktime requested: '" + cmdVal + "'");
 
     tx.nLockTime = (unsigned int) newLocktime;
 }
@@ -212,8 +212,8 @@ static void MutateTxLocktime(CMutableTransaction& tx, const std::string& cmdVal)
 static void MutateTxRBFOptIn(CMutableTransaction& tx, const std::string& strInIdx)
 {
     // parse requested index
-    int inIdx = atoi(strInIdx);
-    if (inIdx < 0 || inIdx >= (int)tx.vin.size()) {
+    int64_t inIdx;
+    if (!ParseInt64(strInIdx, &inIdx) || inIdx < 0 || inIdx >= static_cast<int64_t>(tx.vin.size())) {
         throw std::runtime_error("Invalid TX input index '" + strInIdx + "'");
     }
 
@@ -248,10 +248,10 @@ static void MutateTxAddInput(CMutableTransaction& tx, const std::string& strInpu
     static const unsigned int maxVout = MAX_BLOCK_WEIGHT / (WITNESS_SCALE_FACTOR * minTxOutSz);
 
     // extract and validate vout
-    std::string strVout = vStrInputParts[1];
-    int vout = atoi(strVout);
-    if ((vout < 0) || (vout > (int)maxVout))
-        throw std::runtime_error("invalid TX input vout");
+    const std::string& strVout = vStrInputParts[1];
+    int64_t vout;
+    if (!ParseInt64(strVout, &vout) || vout < 0 || vout > static_cast<int64_t>(maxVout))
+        throw std::runtime_error("invalid TX input vout '" + strVout + "'");
 
     // extract the optional sequence number
     uint32_t nSequenceIn=std::numeric_limits<unsigned int>::max();
@@ -481,10 +481,9 @@ static void MutateTxAddOutScript(CMutableTransaction& tx, const std::string& str
 static void MutateTxDelInput(CMutableTransaction& tx, const std::string& strInIdx)
 {
     // parse requested deletion index
-    int inIdx = atoi(strInIdx);
-    if (inIdx < 0 || inIdx >= (int)tx.vin.size()) {
-        std::string strErr = "Invalid TX input index '" + strInIdx + "'";
-        throw std::runtime_error(strErr.c_str());
+    int64_t inIdx;
+    if (!ParseInt64(strInIdx, &inIdx) || inIdx < 0 || inIdx >= static_cast<int64_t>(tx.vin.size())) {
+        throw std::runtime_error("Invalid TX input index '" + strInIdx + "'");
     }
 
     // delete input from transaction
@@ -494,10 +493,9 @@ static void MutateTxDelInput(CMutableTransaction& tx, const std::string& strInId
 static void MutateTxDelOutput(CMutableTransaction& tx, const std::string& strOutIdx)
 {
     // parse requested deletion index
-    int outIdx = atoi(strOutIdx);
-    if (outIdx < 0 || outIdx >= (int)tx.vout.size()) {
-        std::string strErr = "Invalid TX output index '" + strOutIdx + "'";
-        throw std::runtime_error(strErr.c_str());
+    int64_t outIdx;
+    if (!ParseInt64(strOutIdx, &outIdx) || outIdx < 0 || outIdx >= static_cast<int64_t>(tx.vout.size())) {
+        throw std::runtime_error("Invalid TX output index '" + strOutIdx + "'");
     }
 
     // delete output from transaction
@@ -593,7 +591,7 @@ static void MutateTxSign(CMutableTransaction& tx, const std::string& flagStr)
 
             uint256 txid = ParseHashStr(prevOut["txid"].get_str(), "txid");
 
-            int nOut = atoi(prevOut["vout"].getValStr());
+            const int nOut = prevOut["vout"].get_int();
             if (nOut < 0)
                 throw std::runtime_error("vout must be positive");
 
diff --git a/test/util/data/bitcoin-util-test.json b/test/util/data/bitcoin-util-test.json
index a115aa30d..f2213f4f2 100644
--- a/test/util/data/bitcoin-util-test.json
+++ b/test/util/data/bitcoin-util-test.json
@@ -26,6 +26,12 @@
     "output_cmp": "blanktxv2.json",
     "description": "Creates a blank transaction when nothing is piped into bitcoin-tx (output in json)"
   },
+  { "exec": "./bitcoin-tx",
+    "args": ["-create", "nversion=1foo"],
+    "return_code": 1,
+    "error_txt": "error: Invalid TX version requested",
+    "description": "Tests the check for invalid nversion value"
+  },
   { "exec": "./bitcoin-tx",
     "args": ["-", "delin=1"],
     "input": "tx394b54bb.hex",
@@ -45,6 +51,13 @@
     "error_txt": "error: Invalid TX input index '31'",
     "description": "Attempts to delete an input with a bad index from a transaction. Expected to fail."
   },
+  { "exec": "./bitcoin-tx",
+    "args": ["-", "delin=1foo"],
+    "input": "tx394b54bb.hex",
+    "return_code": 1,
+    "error_txt": "error: Invalid TX input index",
+    "description": "Tests the check for an invalid input index with delin"
+  },
   { "exec": "./bitcoin-tx",
     "args": ["-", "delout=1"],
     "input": "tx394b54bb.hex",
@@ -64,6 +77,13 @@
     "error_txt": "error: Invalid TX output index '2'",
     "description": "Attempts to delete an output with a bad index from a transaction. Expected to fail."
   },
+  { "exec": "./bitcoin-tx",
+    "args": ["-", "delout=1foo"],
+    "input": "tx394b54bb.hex",
+    "return_code": 1,
+    "error_txt": "error: Invalid TX output index",
+    "description": "Tests the check for an invalid output index with delout"
+  },
   { "exec": "./bitcoin-tx",
     "args": ["-", "locktime=317000"],
     "input": "tx394b54bb.hex",
@@ -76,6 +96,29 @@
     "output_cmp": "tt-locktime317000-out.json",
     "description": "Adds an nlocktime to a transaction (output in json)"
   },
+  { "exec": "./bitcoin-tx",
+    "args": ["-create", "locktime=317000foo"],
+    "return_code": 1,
+    "error_txt": "error: Invalid TX locktime requested",
+    "description": "Tests the check for invalid locktime value"
+  },
+  { "exec": "./bitcoin-tx",
+    "args":
+    ["-create",
+     "in=5897de6bd6027a475eadd57019d4e6872c396d0716c4875a5f1a6fcfdf385c1f:0",
+     "replaceable=0foo"],
+    "return_code": 1,
+    "error_txt": "error: Invalid TX input index",
+    "description": "Tests the check for an invalid input index with replaceable"
+  },
+  { "exec": "./bitcoin-tx",
+    "args":
+    ["-create",
+     "in=5897de6bd6027a475eadd57019d4e6872c396d0716c4875a5f1a6fcfdf385c1f:0x"],
+    "return_code": 1,
+    "error_txt": "error: invalid TX input vout",
+    "description": "Tests the check for an invalid vout value when adding an input"
+  },
   { "exec": "./bitcoin-tx",
     "args":
     ["-create",
@@ -225,6 +268,18 @@
     "output_cmp": "txcreatesignv2.hex",
     "description": "Creates a new transaction with a single input and a single output, and then signs the transaction"
   },
+  { "exec": "./bitcoin-tx",
+    "args":
+    ["-create",
+      "in=4d49a71ec9da436f71ec4ee231d04f292a29cd316f598bb7068feccabdc59485:0",
+      "set=privatekeys:[\"5HpHagT65TZzG1PH3CSu63k8DbpvD8s5ip4nEB3kEsreAnchuDf\"]",
+      "set=prevtxs:[{\"txid\":\"4d49a71ec9da436f71ec4ee231d04f292a29cd316f598bb7068feccabdc59485\",\"vout\":\"0foo\",\"scriptPubKey\":\"76a91491b24bf9f5288532960ac687abb035127b1d28a588ac\"}]",
+      "sign=ALL",
+      "outaddr=0.001:193P6LtvS4nCnkDvM9uXn1gsSRqh4aDAz7"],
+    "return_code": 1,
+    "error_txt": "error: prevtxs internal object typecheck fail",
+    "description": "Tests the check for invalid vout index in prevtxs for sign"
+  },
   { "exec": "./bitcoin-tx",
     "args":
     ["-create", "outpubkey=0:02a5613bd857b7048924264d1e70e08fb2a7e6527d32b7ab1bb993ac59964ff397", "nversion=1"],