Chilkat Examples

ChilkatHOMEAndroid™Classic ASPCC++C#Mono C#.NET Core C#C# UWP/WinRTDataFlexDelphi ActiveXDelphi DLLVisual FoxProJavaLianjaMFCObjective-CPerlPHP ActiveXPHP ExtensionPowerBuilderPowerShellPureBasicCkPythonChilkat2-PythonRubySQL ServerSwift 2Swift 3,4,5...TclUnicode CUnicode C++Visual Basic 6.0VB.NETVB.NET UWP/WinRTVBScriptXojo PluginNode.jsExcelGo

VB.NET UWP/WinRT Examples

Web API Categories

ASN.1
Amazon EC2
Amazon Glacier
Amazon S3
Amazon S3 (new)
Amazon SES
Amazon SNS
Amazon SQS
Azure Cloud Storage
Azure Service Bus
Azure Table Service
Base64
Bounced Email
Box
CAdES
CSR
CSV
Certificates
Compression
DKIM / DomainKey
DSA
Diffie-Hellman
Digital Signatures
Dropbox
Dynamics CRM
EBICS
ECC
Ed25519
Email Object
Encryption
FTP
FileAccess
Firebase
GMail REST API
GMail SMTP/IMAP/POP
Geolocation
Google APIs
Google Calendar
Google Cloud SQL
Google Cloud Storage
Google Drive
Google Photos
Google Sheets
Google Tasks
Gzip
HTML-to-XML/Text
HTTP

HTTP Misc
IMAP
JSON
JSON Web Encryption (JWE)
JSON Web Signatures (JWS)
JSON Web Token (JWT)
Java KeyStore (JKS)
MHT / HTML Email
MIME
MS Storage Providers
Microsoft Graph
NTLM
OAuth1
OAuth2
OIDC
Office365
OneDrive
OpenSSL
Outlook
Outlook Calendar
Outlook Contact
PDF Signatures
PEM
PFX/P12
PKCS11
POP3
PRNG
REST
REST Misc
RSA
SCP
SCard
SFTP
SMTP
SSH
SSH Key
SSH Tunnel
ScMinidriver
SharePoint
Socket/SSL/TLS
Spider
Stream
Tar Archive
Upload
WebSocket
XAdES
XML
XML Digital Signatures
XMP
Zip
curl

 

 

 

(VB.NET UWP/WinRT) DSA Signature Create and Verify

Shows how to create a DSA (DSS) signature for the contents of a file. The first step is to create an SHA-1 hash of the file contents. The hash is signed using the Digital Signature Algorithm and the signature bytes are retrieved as a hex-encoded string.

The 2nd part of the example loads the signature and verifies it against the hash.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads

Chilkat for the Universal Windows Platform (UWP)

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

Dim crypt As New Chilkat.Crypt2

crypt.EncodingMode = "hex"
crypt.HashAlgorithm = "sha-1"

' Return the SHA-1 hash of a file.  The file may be any size.
' The Chilkat Crypt component will stream the file when 
' computing the hash, keeping the memory usage constant
' and reasonable.
' The 20-byte SHA-1 hash is returned as a hex-encoded string.
Dim hashStr As String = Await crypt.HashFileENCAsync("hamlet.xml")


Dim dsa As New Chilkat.Dsa

' Load a DSA private key from a PEM file.  Chilkat DSA
' provides the ability to load and save DSA public and private
' keys from encrypted or non-encrypted PEM or DER.
' The LoadText method is for convenience only.  You may
' use any means to load the contents of a PEM file into
' a string.
Dim pemPrivateKey As String
pemPrivateKey = dsa.LoadText("dsa_priv.pem")
Dim success As Boolean = dsa.FromPem(pemPrivateKey)
If (success <> True) Then
    Debug.WriteLine(dsa.LastErrorText)
    Exit Sub
End If


' You may optionally verify the key to ensure that it is a valid
' DSA key.
success = dsa.VerifyKey()
If (success <> True) Then
    Debug.WriteLine(dsa.LastErrorText)
    Exit Sub
End If


' Load the hash to be signed into the DSA object:
success = dsa.SetEncodedHash("hex",hashStr)
If (success <> True) Then
    Debug.WriteLine(dsa.LastErrorText)
    Exit Sub
End If


' Now that the DSA object contains both the private key and hash,
' it is ready to create the signature:
success = dsa.SignHash()
If (success <> True) Then
    Debug.WriteLine(dsa.LastErrorText)
    Exit Sub
End If


' If SignHash is successful, the DSA object contains the
' signature.  It may be accessed as a hex or base64 encoded
' string.  (It is also possible to access directly in byte array form via
' the "Signature" property.)
Dim hexSig As String = dsa.GetEncodedSignature("hex")
Debug.WriteLine("Signature:")
Debug.WriteLine(hexSig)

' -----------------------------------------------------------
' Step 2: Verify the DSA Signature
' -----------------------------------------------------------

Dim dsa2 As New Chilkat.Dsa

' Load the DSA public key to be used for verification:
Dim pemPublicKey As String
pemPublicKey = dsa2.LoadText("dsa_pub.pem")
success = dsa2.FromPublicPem(pemPublicKey)
If (success <> True) Then
    Debug.WriteLine(dsa2.LastErrorText)
    Exit Sub
End If


' Load the hash to be verified against the signature.
success = dsa2.SetEncodedHash("hex",hashStr)
If (success <> True) Then
    Debug.WriteLine(dsa2.LastErrorText)
    Exit Sub
End If


' Load the signature:
success = dsa2.SetEncodedSignature("hex",hexSig)
If (success <> True) Then
    Debug.WriteLine(dsa2.LastErrorText)
    Exit Sub
End If


' Verify:
success = dsa2.Verify()
If (success <> True) Then
    Debug.WriteLine(dsa2.LastErrorText)
Else
    Debug.WriteLine("DSA Signature Verified!")
End If


 

© 2000-2022 Chilkat Software, Inc. All Rights Reserved.