HMAC SHA1 for Amazon S3

Demonstrates the HMAC SHA1 computation required by the Amazon S3 web service.

Download: Chilkat .NET Assemblies

'  This example uses sample data from:
'  http://docs.amazonwebservices.com/AmazonS3/2006-03-01/RESTAuthentication.html
Dim strToSign As String
strToSign = "GET" & vbLf + vbLf & vbLf & "Tue, 27 Mar 2007 19:36:42 +0000" & vbLf & "/johnsmith/photos/puppy.jpg"

Dim crypt As New Chilkat.Crypt2()

Dim success As Boolean
success = crypt.UnlockComponent("Anything for 30-day trial.")
If (success <> true) Then
    '  Unlock Failed.
    MsgBox(crypt.LastErrorText)
    Exit Sub
End If


'  We want SHA1 for the HMAC hash algorithm:
crypt.HashAlgorithm = "sha1"


Dim AWSAccessKeyId As String
AWSAccessKeyId = "0PN5J17HBGZHT7JJ3X82"
Dim AWSSecretAccessKey As String
AWSSecretAccessKey = "uV3F3YluFJax1cknvbcGwgjvx4QpvB+leU8dUj2o"

'  Set the HMAC secret key:
crypt.SetHmacKeyString(AWSSecretAccessKey)

'  By setting the charset = "utf-8", the string will be converted
'  to utf-8 (internal to the Chilkat component) prior to signing:
crypt.Charset = "utf-8"

'  Indicate that Base64 output is desired:
crypt.EncodingMode = "base64"

Dim signature As String
signature = crypt.HmacStringENC(strToSign)
TextBox1.Text = TextBox1.Text & crypt.LastErrorText & vbCrLf

'  Display the signature as part of the HTTP Authorization header:
TextBox1.Text = TextBox1.Text & "Authorization: AWS " _
     & AWSAccessKeyId & ":" & signature & vbCrLf

TextBox1.Text = TextBox1.Text & "Expected:      AWS 0PN5J17HBGZHT7JJ3X82:xXjDGYUmKxnwqr5KXNPGldn5LbA=" & vbCrLf