(Excel) Signing HTTP Messages

Demonstrates how to sign HTTP messages per draft-cavage-http-signatures-10

For more information, see https://tools.ietf.org/html/draft-cavage-http-signatures-10

Download Excel Class Modules Chilkat Excel Class Modules

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.


bCrlf = True
Dim sbPublicKeyPem As Chilkat.StringBuilder
Set sbPublicKeyPem = Chilkat.NewStringBuilder
Dim success As Boolean
success = sbPublicKeyPem.AppendLine("-----BEGIN PUBLIC KEY-----",bCrlf)
success = sbPublicKeyPem.AppendLine("MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDCFENGw33yGihy92pDjZQhl0C3",bCrlf)
success = sbPublicKeyPem.AppendLine("6rPJj+CvfSC8+q28hxA161QFNUd13wuCTUcq0Qd2qsBe/2hFyc2DCJJg0h1L78+6",bCrlf)
success = sbPublicKeyPem.AppendLine("Z4UMR7EOcpfdUE9Hf3m/hs+FUR45uBJeDK1HSFHD8bHKD6kv8FPGfJTotc+2xjJw",bCrlf)
success = sbPublicKeyPem.AppendLine("oYi+1hqp1fIekaxsyQIDAQAB",bCrlf)
success = sbPublicKeyPem.AppendLine("-----END PUBLIC KEY-----",bCrlf)

Dim pubKey As Chilkat.PublicKey
Set pubKey = Chilkat.NewPublicKey
success = pubKey.LoadFromString(sbPublicKeyPem.GetAsString())

Dim sbPrivateKeyPem As Chilkat.StringBuilder
Set sbPrivateKeyPem = Chilkat.NewStringBuilder
success = sbPrivateKeyPem.AppendLine("-----BEGIN RSA PRIVATE KEY-----",bCrlf)
success = sbPrivateKeyPem.AppendLine("MIICXgIBAAKBgQDCFENGw33yGihy92pDjZQhl0C36rPJj+CvfSC8+q28hxA161QF",bCrlf)
success = sbPrivateKeyPem.AppendLine("NUd13wuCTUcq0Qd2qsBe/2hFyc2DCJJg0h1L78+6Z4UMR7EOcpfdUE9Hf3m/hs+F",bCrlf)
success = sbPrivateKeyPem.AppendLine("UR45uBJeDK1HSFHD8bHKD6kv8FPGfJTotc+2xjJwoYi+1hqp1fIekaxsyQIDAQAB",bCrlf)
success = sbPrivateKeyPem.AppendLine("AoGBAJR8ZkCUvx5kzv+utdl7T5MnordT1TvoXXJGXK7ZZ+UuvMNUCdN2QPc4sBiA",bCrlf)
success = sbPrivateKeyPem.AppendLine("QWvLw1cSKt5DsKZ8UETpYPy8pPYnnDEz2dDYiaew9+xEpubyeW2oH4Zx71wqBtOK",bCrlf)
success = sbPrivateKeyPem.AppendLine("kqwrXa/pzdpiucRRjk6vE6YY7EBBs/g7uanVpGibOVAEsqH1AkEA7DkjVH28WDUg",bCrlf)
success = sbPrivateKeyPem.AppendLine("f1nqvfn2Kj6CT7nIcE3jGJsZZ7zlZmBmHFDONMLUrXR/Zm3pR5m0tCmBqa5RK95u",bCrlf)
success = sbPrivateKeyPem.AppendLine("412jt1dPIwJBANJT3v8pnkth48bQo/fKel6uEYyboRtA5/uHuHkZ6FQF7OUkGogc",bCrlf)
success = sbPrivateKeyPem.AppendLine("mSJluOdc5t6hI1VsLn0QZEjQZMEOWr+wKSMCQQCC4kXJEsHAve77oP6HtG/IiEn7",bCrlf)
success = sbPrivateKeyPem.AppendLine("kpyUXRNvFsDE0czpJJBvL/aRFUJxuRK91jhjC68sA7NsKMGg5OXb5I5Jj36xAkEA",bCrlf)
success = sbPrivateKeyPem.AppendLine("gIT7aFOYBFwGgQAQkWNKLvySgKbAZRTeLBacpHMuQdl1DfdntvAyqpAZ0lY0RKmW",bCrlf)
success = sbPrivateKeyPem.AppendLine("G6aFKaqQfOXKCyWoUiVknQJAXrlgySFci/2ueKlIE1QqIiLSZ8V8OlpFLRnb1pzI",bCrlf)
success = sbPrivateKeyPem.AppendLine("7U1yQXnTAEFYM560yJlzUpOb1V4cScGd365tiSMvxLOvTA==",bCrlf)
success = sbPrivateKeyPem.AppendLine("-----END RSA PRIVATE KEY-----",bCrlf)

Dim privKey As Chilkat.PrivateKey
Set privKey = Chilkat.NewPrivateKey
success = privKey.LoadPem(sbPrivateKeyPem.GetAsString())

'    All examples use this request:
' 
'    POST /foo?param=value&pet=dog HTTP/1.1
'    Host: example.com
'    Date: Sun, 05 Jan 2014 21:31:40 GMT
'    Content-Type: application/json
'    Digest: SHA-256=X48E9qOokqqrvdts8nOJRJN3OWDUoyWxBf7kbu9DBPE=
'    Content-Length: 18
' 
'    {"hello": "world"}

' C.1.  Default Test
' 
'    If a list of headers is not included, the date is the only header
'    that is signed by default.  The string to sign would be:
' 
'    date: Sun, 05 Jan 2014 21:31:40 GMT
' 
'    The Authorization header would be:
' 
'    Authorization: Signature keyId="Test",algorithm="rsa-sha256",
'    signature="SjWJWbWN7i0wzBvtPl8rbASWz5xQW6mcJmn+ibttBqtifLN7Sazz
'    6m79cNfwwb8DMJ5cou1s7uEGKKCs+FLEEaDV5lp7q25WqS+lavg7T8hc0GppauB
'    6hbgEKTwblDHYGEtbGmtdHgVCk9SuS13F0hZ8FD0k/5OxEPXe5WozsbM="
' 
'    The Signature header would be:
' 
'    Signature: keyId="Test",algorithm="rsa-sha256",
'    signature="SjWJWbWN7i0wzBvtPl8rbASWz5xQW6mcJmn+ibttBqtifLN7Sazz
'    6m79cNfwwb8DMJ5cou1s7uEGKKCs+FLEEaDV5lp7q25WqS+lavg7T8hc0GppauB
'    6hbgEKTwblDHYGEtbGmtdHgVCk9SuS13F0hZ8FD0k/5OxEPXe5WozsbM="
' 

Dim dtNow As Chilkat.CkDateTime
Set dtNow = Chilkat.NewCkDateTime
success = dtNow.SetFromCurrentSystemTime()

dateStr = dtNow.GetAsRfc822(False)

' To duplicate the above result, we'll hard-code the date string.
dateStr = "Sun, 05 Jan 2014 21:31:40 GMT"

Dim rsa As Chilkat.Rsa
Set rsa = Chilkat.NewRsa
success = rsa.ImportPrivateKeyObj(privKey)
If (success = False) Then
    Debug.Print rsa.LastErrorText
    Exit Sub
End If

Dim sbStringToSign As Chilkat.StringBuilder
Set sbStringToSign = Chilkat.NewStringBuilder
success = sbStringToSign.Append("date: ")
success = sbStringToSign.Append(dateStr)

rsa.EncodingMode = "base64"

b64Signature = rsa.SignStringENC(sbStringToSign.GetAsString(),"SHA256")
Debug.Print b64Signature
Debug.Print "---------------------------"

' The result should be:
' SjWJWbWN7i0wzBvtPl8rbASW ... FD0k/5OxEPXe5WozsbM=

' ----------------------------------------------------------------------------------------------------

' C.2.  Basic Test
' 
'    The minimum recommended data to sign is the (request-target), host,
'    and date.  In this case, the string to sign would be:
' 
'    (request-target): post /foo?param=value&pet=dog
'    host: example.com
'    date: Sun, 05 Jan 2014 21:31:40 GMT
' 
'    The Authorization header would be:
' 
'    Authorization: Signature keyId="Test",algorithm="rsa-sha256",
'    headers="(request-target) host date", signature="qdx+H7PHHDZgy4
'    y/Ahn9Tny9V3GP6YgBPyUXMmoxWtLbHpUnXS2mg2+SbrQDMCJypxBLSPQR2aAjn
'    7ndmw2iicw3HMbe8VfEdKFYRqzic+efkb3nndiv/x1xSHDJWeSWkx3ButlYSuBs
'    kLu6kd9Fswtemr3lgdDEmn04swr2Os0="

sbStringToSign.Clear 
success = sbStringToSign.Append("(request-target): ")
success = sbStringToSign.AppendLine("post /foo?param=value&pet=dog",False)
success = sbStringToSign.Append("host: ")
success = sbStringToSign.AppendLine("example.com",False)
success = sbStringToSign.Append("date: ")
success = sbStringToSign.Append(dateStr)

Debug.Print "StringToSign:"
Debug.Print sbStringToSign.GetAsString()
b64Signature = rsa.SignStringENC(sbStringToSign.GetAsString(),"SHA256")
Debug.Print b64Signature
Debug.Print "---------------------------"

' The result should be:
' qdx+H7PHHDZgy4y/Ahn ... mn04swr2Os0=