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) Exporting and Importing Accumulated Entropy

When a system starts, a good established source of entropy may be lacking. The Fortuna algorithm keeps 32 internal entropy pools. When AddEntropy is called, it is added to these internal pools. (The details of the Fortuna algorithm can be read elsewhere.)

This example demonstrates how the entropy that has accumulated within the internal pools can be exported (such as when an application exits) and then imported when an application starts. (It is the application's job to persist the exported entropy to a database, file, etc.)

Importing entropy helps ensure an application is beginning with an adequate source of entropy for random number generation.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads

Chilkat for the Universal Windows Platform (UWP)

' All Chilkat classes can be unlocked at once at the beginning of a program
' by calling UnlockBundle.  It requires a Bundle unlock code.
Dim chilkatGlob As New Chilkat.Global
Dim success As Boolean = chilkatGlob.UnlockBundle("Anything for 30-day trial.")
If (success <> True) Then
    Debug.WriteLine(chilkatGlob.LastErrorText)
    Exit Sub
End If


Dim fortuna As New Chilkat.Prng

' Generate random data and periodically add entropy...
success = fortuna.AddEntropy(fortuna.GetEntropy(32,"hex"),"hex")
Debug.WriteLine(fortuna.GenRandom(16,"hex"))
Debug.WriteLine(fortuna.GenRandom(16,"hex"))
Debug.WriteLine(fortuna.GenRandom(16,"hex"))
success = fortuna.AddEntropy(fortuna.GetEntropy(16,"hex"),"hex")
Debug.WriteLine(fortuna.GenRandom(16,"hex"))
Debug.WriteLine(fortuna.GenRandom(16,"hex"))
Debug.WriteLine(fortuna.GenRandom(16,"hex"))
success = fortuna.AddEntropy(fortuna.GetEntropy(16,"hex"),"hex")
Debug.WriteLine(fortuna.GenRandom(16,"hex"))
Debug.WriteLine(fortuna.GenRandom(16,"hex"))
Debug.WriteLine(fortuna.GenRandom(16,"hex"))
success = fortuna.AddEntropy(fortuna.GetEntropy(16,"hex"),"hex")
Debug.WriteLine(fortuna.GenRandom(16,"hex"))
Debug.WriteLine(fortuna.GenRandom(16,"hex"))
Debug.WriteLine(fortuna.GenRandom(16,"hex"))

Dim exportedEntropy As String = fortuna.ExportEntropy()
' The application would persist the exported entropy in some way,
' such as to a file, or to a database, etc.

' Create a new PRNG object and initialize the internal entropy pools
' with the previously exported entropy:
Dim fortuna2 As New Chilkat.Prng
success = fortuna2.ImportEntropy(exportedEntropy)

' Generate more random data, continuing to add entropy as we go along..
Debug.WriteLine(fortuna2.GenRandom(16,"hex"))
Debug.WriteLine(fortuna2.GenRandom(16,"hex"))
Debug.WriteLine(fortuna2.GenRandom(16,"hex"))
success = fortuna2.AddEntropy(fortuna2.GetEntropy(16,"hex"),"hex")
Debug.WriteLine(fortuna2.GenRandom(16,"hex"))
Debug.WriteLine(fortuna2.GenRandom(16,"hex"))
Debug.WriteLine(fortuna2.GenRandom(16,"hex"))
success = fortuna2.AddEntropy(fortuna2.GetEntropy(16,"hex"),"hex")
' ..

 

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