diff --git a/package.json b/package.json
index 3a0824cd..3eb69900 100644
--- a/package.json
+++ b/package.json
@@ -63,7 +63,7 @@
     "oboe": "2.1.3",
     "request": "2.87.0",
     "requestretry": "^2.0.2",
-    "scrypt.js": "0.2.0",
+    "scryptsy": "2.1.0",
     "underscore": "^1.9.1",
     "utf8": "2.1.1",
     "uuid": "2.0.1",
diff --git a/packages/caver-klay/caver-klay-accounts/src/index.js b/packages/caver-klay/caver-klay-accounts/src/index.js
index 060792a6..97335207 100644
--- a/packages/caver-klay/caver-klay-accounts/src/index.js
+++ b/packages/caver-klay/caver-klay-accounts/src/index.js
@@ -35,7 +35,7 @@ var RLP = require("eth-lib/lib/rlp");
 var Nat = require("eth-lib/lib/nat");
 var Bytes = require("eth-lib/lib/bytes");
 var cryp = (typeof global === 'undefined') ? require('crypto-browserify') : require('crypto');
-var scryptsy = require('scrypt.js');
+var scrypt = require('./scrypt');
 var uuid = require('uuid');
 var utils = require('../../../caver-utils');
 var helpers = require('../../../caver-core-helpers');
@@ -470,7 +470,7 @@ Accounts.prototype.decrypt = function (v3Keystore, password, nonStrict) {
         kdfparams = json.crypto.kdfparams;
 
         // FIXME: support progress reporting callback
-        derivedKey = scryptsy(new Buffer(password), new Buffer(kdfparams.salt, 'hex'), kdfparams.n, kdfparams.r, kdfparams.p, kdfparams.dklen);
+        derivedKey = scrypt(new Buffer(password), new Buffer(kdfparams.salt, 'hex'), kdfparams.n, kdfparams.r, kdfparams.p, kdfparams.dklen);
     } else if (json.crypto.kdf === 'pbkdf2') {
         kdfparams = json.crypto.kdfparams;
 
@@ -589,7 +589,7 @@ Accounts.prototype.encrypt = function (privateKey, password, options) {
         kdfparams.n = options.n || 4096; // 2048 4096 8192 16384
         kdfparams.r = options.r || 8;
         kdfparams.p = options.p || 1;
-        derivedKey = scryptsy(new Buffer(password), salt, kdfparams.n, kdfparams.r, kdfparams.p, kdfparams.dklen);
+        derivedKey = scrypt(new Buffer(password), salt, kdfparams.n, kdfparams.r, kdfparams.p, kdfparams.dklen);
     } else {
         throw new Error('Unsupported kdf');
     }
diff --git a/packages/caver-klay/caver-klay-accounts/src/scrypt.js b/packages/caver-klay/caver-klay-accounts/src/scrypt.js
new file mode 100644
index 00000000..291685b0
--- /dev/null
+++ b/packages/caver-klay/caver-klay-accounts/src/scrypt.js
@@ -0,0 +1,92 @@
+/*
+    Modifications copyright 2019 The caver-js Authors
+    This file is part of web3.js.
+
+    web3.js is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    web3.js is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with web3.js.  If not, see <http://www.gnu.org/licenses/>.
+
+    This file is derived from web3.js/packages/web3-eth-accounts/src/scrpyt.js (2019/09/03).
+    Modified and improved for the caver-js development.
+*/
+
+var scryptsy = require('scryptsy');
+
+var scrypt;
+
+var isNode = Object.prototype.toString.call(typeof process !== 'undefined' ? process : 0) === '[object process]';
+if (isNode) {
+    var NODE_MIN_VER_WITH_BUILTIN_SCRYPT = '10.5.0';
+    var NODE_MIN_VER_INCOMPAT_SCRYPT_PKG = '12.0.0';
+    var semver = require('semver');
+    var useNodeBuiltin = isNode && semver.Range('>=' + NODE_MIN_VER_WITH_BUILTIN_SCRYPT).test(process.version);
+
+    var tryScryptPkg = (function() {
+        var scryptPkg;
+        return function() {
+            if (scryptPkg !== undefined) { return scryptPkg; }
+            try {
+                scryptPkg = (function(m) { return require(m); })('scrypt');
+            } catch (e) {
+                if (/was compiled against a different/.test(e.message)) {
+                    throw e;
+                }
+                scryptPkg = null;
+            }
+            return scryptPkg;
+        };
+    })();
+
+    var canImprove = function(nodeVer) {
+        return 'can improve web3\'s peformance when running Node.js versions older than ' + nodeVer + ' by installing the (deprecated) scrypt package in your project';
+    };
+
+    if (useNodeBuiltin) {
+        var crypto = require('crypto');
+        var fallbackCount = 0;
+        scrypt = function(key, salt, N, r, p, dkLen) {
+            try {
+                return crypto.scryptSync(key, salt, dkLen, {N: N, r: r, p: p});
+            } catch (e) {
+                if (/scrypt:memory limit exceeded/.test(e.message)) {
+                    var scryptPkg = tryScryptPkg();
+                    if (scryptPkg) {
+                        return scryptPkg.hashSync(key, {N: N, r: r, p: p}, dkLen, salt);
+                    }
+                    fallbackCount += 1;
+                    console.warn(
+                        '\x1b[33m%s\x1b[0m',
+                        'Memory limit exceeded for Node\'s built-in crypto.scrypt, falling back to scryptsy (times: ' + fallbackCount + '), if this happens frequently you ' + canImprove(NODE_MIN_VER_INCOMPAT_SCRYPT_PKG)
+                    );
+                    return scryptsy(key, salt, N, r, p, dkLen);
+                }
+                throw e;
+            }
+        };
+    } else {
+        var scryptPkg = tryScryptPkg();
+        if (scryptPkg) {
+            scrypt = function(key, salt, N, r, p, dkLen) {
+                return scryptPkg.hashSync(key, {N: N, r: r, p: p}, dkLen, salt);
+            };
+        } else {
+            console.warn(
+                '\x1b[33m%s\x1b[0m',
+                'You ' + canImprove(NODE_MIN_VER_WITH_BUILTIN_SCRYPT)
+            );
+        }
+    }
+}
+
+scrypt = scrypt || scryptsy;
+
+module.exports = scrypt;