AWS Signature Version 4 S3 Download with Node.js

I followed AWS example how to generate V4 HMAC signature. I've done this successfully in Java, but I'm trying to get it to work in Node / JavaScript. When I use my code, I generate all the correct intermediate keys in their first example below, but in the next example, when the StringToSign test is given, the same code that generated the correct intermediate keys was unable to generate the assumed correct signature.

Correct intermediate keys:

secretkey = 'wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY'
dateStamp = '20120215'
regionName = 'us-east-1'
serviceName = 'iam'

kSecret  = '41575334774a616c725855746e46454d492f4b374d44454e472b62507852666943594558414d504c454b4559'
kDate    = '969fbb94feb542b71ede6f87fe4d5fa29c789342b0f407474670f0c2489e0a0d'
kRegion  = '69daa0209cd9c5ff5c8ced464a696fd4252e981430b10e3d3fd8e2f197d7a70c'
kService = 'f72cfd46f26bc4643f06a11eabb6c0ba18780c19a8da0c31ace671265e3c87fa'
kSigning = 'f4780e2d9f65fa895f9c67b32ce1baf0b0d8a43505a000a1a9e090d414db404d'

      

        
        
        
      

    

http://docs.aws.amazon.com/general/latest/gr/signature-v4-examples.html .

Failure on next input

secretkey = 'wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY'
dateStamp = '20151229'
regionName = 'us-east-1'
serviceName = 's3'

      

        
        
        
      

    

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

Correct signature: 46503978d3596de22955b4b18d6dfb1d54e8c5958727d5bdcd02cc1119c60fc9 My signature: e7318f0bfd7d86fb9ba81c314f62192ee2baf7273792ef01ffafeb430fc2

http://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-post-example.html

My code

var crypto = require("crypto-js")

module.exports.getSignatureKey = function(key, dateStamp, regionName, serviceName) {
    var kSecret = "AWS4" + key
    var kDate = crypto.HmacSHA256(dateStamp, kSecret)
    var kRegion = crypto.HmacSHA256(regionName, kDate)
    var kService = crypto.HmacSHA256(serviceName, kRegion)
    var kSigning = crypto.HmacSHA256("aws4_request", kService)
    return kSigning;
}

module.exports.sign = function(signatureKey,stringToSign) {
    var unencodedSignature = crypto.HmacSHA256(stringToSign,signatureKey)
    return unencodedSignature
}

module.exports.getSignature = function(stringToSign,secretKey,dateStamp,regionName, serviceName) {
    var signingKey = this.getSignatureKey(secretKey,dateStamp,regionName,serviceName)

    return this.sign(signingKey,stringToSign)
}