function hex2a(hex) { var str = ''; for (var i = 0; i < hex.length; i += 2) str += String.fromCharCode(parseInt(hex.substr(i, 2), 16)); return str; } //Raw cookie var cookie = "B417B464CA63FE780584563D2DA4709B03F6195189044C26A29770F3203881DD90B1428139088D945CF6807CA408F201DABBADD59CE1D740F853A894692273F1CA83EC3F26493744E3D25D720374E03393F71E21BE2D96B6110CB7AC12E44447FFBD810D3D57FBACA8DF5249EB503C3DFD255692409F084650EFED205388DD8C08BF7B941E1AC1B3B70B9A8E09118D756BEAFF25834E72357FD40E80E76458091224FAE8"; //decryptionKey from issuers var deckey = "FFA87B82D4A1BEAA15C06F6434A7EB2251976A838784E134900E6629B9F954B7"; var crypto = require('crypto'); var ivc = cookie, iv, cipherText, ivSize = 16, res = ""; ivc = new Buffer(ivc, 'hex'); iv = new Buffer(ivSize); cipherText = new Buffer(ivc.length - ivSize); ivc.copy(iv, 0, 0, ivSize); ivc.copy(cipherText, 0, ivSize); c = crypto.createDecipheriv('aes-256-cbc', hex2a(deckey), iv.toString('binary')); res = c.update(cipherText, "binary", "utf8"); res += c.final('utf8'); console.log(res);