Amazon AWS S4 Signature Does Not Match
I am having some issues generating a valid signature for Amazon AWS S4 using temporary access keys. I have placed my code below if anybody wouldn't mind spotting out any mistakes I may have made!
The response I am getting from their service every time is: "SignatureDoesNotMatch" = "The request signature we calculated does not match the signature you provided. Check your key and signing method".
Even when taking the suggested signature to use on the same timestamp I am getting exactly the same response.
I'm a bit stumped on this one now, was hoping to have a very simple standalone function for this but after many hours of attempting different angles I don't seem to be getting anywhere!
Imports System.Net
Imports System.IO
Imports System.Text
Imports System.Security.Cryptography
Public Class Form1
' Variables
Dim URL As String = "https://s3-us-west-2.amazonaws.com/xxx.com/CFCD208495D565EF66E7DFF9F98764DA_E0965B2E-0D0F-4CC5-B82B-AED142C3F171_p.jpg"
Dim ProfileImagePath As String = "C:image.jpg"
Dim AccessKeyId As String = "xxxxxxRWA52ZL6XLEA"
Dim SessionToken As String = "xxxxx//////////wEaDBTonaKkiE9LmSoeWiLOA6.....=="
Dim SecretAccessKey As String = "xxxxxxGzXPJ1LUp7onT3lol9Vdb3dbySN"
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Try
UploadImage(URL, ProfileImagePath, AccessKeyId, SessionToken, SecretAccessKey)
MessageBox.Show("Successful")
Catch ex As Exception
MessageBox.Show("Failed: " & ex.Message)
End Try
End Sub
Friend Function UploadImage(ByVal URL As String, ByVal FilePath As String, ByVal AccessKeyId As String, ByVal SessionToken As String, ByVal SecretAccessKey As String) As String
ServicePointManager.ServerCertificateValidationCallback = (Function(sender, certificate, chain, sslPolicyErrors) True)
System.Net.ServicePointManager.Expect100Continue = False
' Variables
Dim CurrentDate As DateTime = DateTime.Now()
Dim FileData As System.Drawing.Image
Dim fs As System.IO.FileStream
Dim Content As String = ""
' Set Headers To Encode
Dim builder As StringBuilder = New StringBuilder()
builder.Append("PUT")
builder.Append(vbLf)
builder.Append(Split(URL, ".amazonaws.com")(1))
builder.Append(vbLf)
builder.Append("host:s3-us-west-2.amazonaws.com")
builder.Append(vbLf)
builder.Append("x-amz-content-sha256:STREAMING-AWS4-HMAC-SHA256-PAYLOAD")
builder.Append(vbLf)
builder.Append("x-amz-date:" & CurrentDate.ToString("yyyyMMddTHHmmssZ"))
builder.Append(vbLf)
builder.Append("x-amz-security-token:" & URLEncode(SessionToken))
builder.Append(vbLf)
builder.Append("host;x-amz-content-sha256;x-amz-date;x-amz-security-token")
' Add To String
Dim canonicalString As String = builder.ToString()
' Hex Encode
Dim hashedCanonicalRequest As String = HexEncode(Hash(ToBytes(canonicalString)))
Dim signedHeaders As String = "content-type;host;x-amz-content-sha256;x-amz-date;x-amz-security-token"
Dim stringToSign As String = "AWS4-HMAC-SHA256" & vbLf & CurrentDate.ToString("yyyyMMddTHHmmssZ") & vbLf & DateTime.Now().ToString("yyyyMMdd") & "/us-west-2/s3/aws4_request" & vbLf & hashedCanonicalRequest
Dim signingKey As Byte() = getSignatureKey(SecretAccessKey, DateTime.Now().ToString("yyyyMMdd"), "us-west-2", "aws4_request")
Dim StringSignature = HexEncode(HmacSha256(stringToSign, signingKey))
' Save Image To Memory
Dim ms As New MemoryStream()
Try
fs = New System.IO.FileStream(FilePath, System.IO.FileMode.Open)
FileData = Image.FromStream(fs)
FileData.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg)
Catch ex As Exception
Throw New Exception("Failed To Load Image: " & ex.Message)
End Try
' Variables
Dim req As HttpWebRequest = DirectCast(WebRequest.Create(URL), HttpWebRequest)
' Set Request Settings
req.Method = "PUT"
req.Accept = "*/*"
req.Headers("Authorization") = "AWS4-HMAC-SHA256 Credential=" & AccessKeyId & "/" & DateTime.Now().ToString("yyyyMMdd") & "/us-west-2/s3/aws4_request, SignedHeaders=host;x-amz-content-sha256;x-amz-date;x-amz-security-token, Signature=" & StringSignature
req.Headers.Add("X-Amz-Date", CurrentDate.ToString("yyyyMMddTHHmmssZ"))
req.UserAgent = "aws-sdk-iOS/2.2.0 iOS/10.2.1 en_GB"
req.Headers.Add("X-Amz-Security-Token", SessionToken)
req.ContentType = "image/jpeg"
req.Headers.Add("x-amz-content-sha256", "STREAMING-AWS4-HMAC-SHA256-PAYLOAD")
' Set Bytes
Dim imageBytes As Byte() = ms.ToArray()
Dim postBytes As Byte() = New Byte((imageBytes.Length - 1)) {}
req.ContentLength = postBytes.Length
Buffer.BlockCopy(imageBytes, 0, postBytes, 0, imageBytes.Length)
ms.Close()
' Get/Read Stream
Dim postreqstream As Stream = req.GetRequestStream()
Dim postresponse As HttpWebResponse
postreqstream.Write(postBytes, 0, postBytes.Length)
postreqstream.Close()
postresponse = DirectCast(req.GetResponse(), HttpWebResponse)
Dim postreqreader As New StreamReader(postresponse.GetResponseStream())
Content = postreqreader.ReadToEnd
' Close Connection
postresponse.Close()
fs.Close()
Return Content
End Function
Private Shared Function getSignatureKey(key As String, dateStamp As String, regionName As String, serviceName As String) As Byte()
Dim kSecret As Byte() = Encoding.UTF8.GetBytes(("AWS4" + key).ToCharArray())
Dim kDate As Byte() = HmacSHA256(dateStamp, kSecret)
Dim kRegion As Byte() = HmacSHA256(regionName, kDate)
Dim kService As Byte() = HmacSHA256(serviceName, kRegion)
Dim kSigning As Byte() = HmacSHA256("aws4_request", kService)
Return kSigning
End Function
Private Shared Function ToBytes(str As String) As Byte()
Return Encoding.UTF8.GetBytes(str.ToCharArray())
End Function
Private Shared Function HexEncode(bytes As Byte()) As String
Return BitConverter.ToString(bytes).Replace("-", String.Empty).ToLowerInvariant()
End Function
Private Shared Function Hash(bytes As Byte()) As Byte()
Dim sha256__1 = SHA256.Create()
Return sha256__1.ComputeHash(bytes)
End Function
Private Shared Function HmacSha256(data As [String], key As Byte()) As Byte()
Return New HMACSHA256(key).ComputeHash(ToBytes(data))
End Function
Friend Function URLEncode(ByVal URL As String) As String
If URL = Nothing OrElse URL = "" Then Return ""
Return Uri.EscapeDataString(URL)
End Function
End Class
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