Using Win32 functions in Visual FoxPro Image Gallery
Code examples:
GetFileOwner - Get the owner of an NTFS file
Placing On-screen Alert on top of all windows
Detecting changes in connections to removable drives (VFP9)
Running MSDOS Shell as a child process with redirected input and output (smarter RUN command)
Simple printer queue monitor: deletes, pauses, resumes print jobs for local printer
Converting Unicode data from the Clipboard to a character string using a given code page
How to print FoxPro form
Windows Shell Icons displayed and exported to ICO files (Vista)
Accessing Adobe Reader 7.0 main menu from VFP application
Displaying the associated icons and descriptions for files and folders
How to change the name and the size of the font in the MessageBox dialog
Round FoxPro form
Adding user-defined items to the Control Menu of VFP form (requires VFP9)
Displaying Windows shell folders in TreeView control with Visual FoxPro FLL
Establishing connection using the SQLDriverConnect
How to view system icons for the classes installed on the local machine
Winsock: connecting to a news server (NNTP, port 119)
Converting image file to .ICO file
GDI+: how to make VFP controls visually shake and shudder
How to make application automatically close all documents it opened
How to print a bitmap file
Vertical Label control
Class for sound recording
How to display the Properties dialog box for a file (ShellExecuteEx)
How to create MD-5 and SHA-1 hash values from a string

User rating: 0/10 (0 votes)
Rate this code sample:
  • ~
More code examples    Listed functions    Add comment     W32 Constants      Translate this page Printer friendly version of this code sample
Versions:
click to open
Before you begin:
Test the presented class as follows:
obj = CREATEOBJECT("TheHash")

? obj.CreateSHA1("test string")

* returns 661295C9CBF9D6B2F6428414504A8DEED3020641

? obj.CreateMD5("test string")
* returns 6F8DB599DE986FAB7A21625B7916589C

See also:
  • Simple class that encrypts and decrypts files using Cryptography API Functions
  • CryptoAPI: Collection of Providers class
  • WinINet function CreateMD5SSOHash
  •  
      Members area. Log in to view this example.
     
      User name:
      Password:
     
     
      Forgot your password?
     
      Sign up for
    the Membership
     
      Buy this example for $10.00
    Instant email delivery.

    Read more...
     


    User rating: 0/10 (0 votes)
    Rate this code sample:
    • ~
    3548 bytes  
    Created: 2005-03-07 15:21:11  
    Modified: 2013-09-20 13:30:28  
    Visits in 7 days: 115  
    Listed functions:
    CryptAcquireContext
    CryptCreateHash
    CryptDestroyHash
    CryptGetHashParam
    CryptHashData
    CryptReleaseContext
    GetLastError
    Printer friendly API declarations
    My comment:
    Transact-SQL HASHBYTES() function computes MD5 and SHA1 hashes identical to those produced by VFP and C# code samples above.



    * * *
    One-way hash functions can be used for creating a fingerprint for a block of data.

    Also hash functions can be used to evaluate passwords. In Users table of your FoxPro application you store not passwords but their hash values.

    It is extremely difficult, if ever possible, to find the original string for a given hash value -- depends on the hash algorithm as well as computer power and methodology you have.

    * * *
    Message Digest: The representation of text in the form of a single string of digits, created using a formula called a one-way hash function.

    One-Way Hash Function: An algorithm that turns messages or text into a fixed string of digits, usually for security or data management purposes. The "one way" means that it is nearly impossible to derive the original text from the string.

    Hash Collision: More than one input message producing identical hash output.

    * * *
    Secure Hash Algorithm, a hash function developed by the NSA for use with NIST Digital Signature Standard (DSS). NSA almost immediately developed a minor change known as SHA-1. Both SHA and SHA-1 produce a 160-bit digest. SHA-1 is used in SSL.

    * * *
    MD-5 is a one-way message-digest hash function. The algorithm processes input text and creates a 128-bit message digest which is unique to the message and can be used to verify data integrity.

    MD-5 was developed by Ron Rivest and is intended to be used in digital signatures applications. Earlier message digest algorithms include obsolete MD-2 and MD-4.

    See also:
  • RFC 1321 - The MD5 Message-Digest Algorithm
  • What are MD2, MD4, and MD5?
  • Example C Program: Creating an MD-5 Hash From File Content.
  • MD5 Online Cracking using Rainbow Tables
  • RFC 3174 - US Secure Hash Algorithm 1 (SHA1)
  • More on Newly Broken SHA1 on Alex Feldstein"s blog
  • Hash Collisions Q&A
  • Word Index links for this example:
    Translate this page:
      Spanish    Portuguese    German    French    Italian  
    FreeTranslation.com offers instant, free translations of text or web pages.
    User Contributed Notes:
    Malcolm Greene | 2005-04-06 00:16:27
    Are there any Windows version (or service pack) dependencies with this code (advapi32.dll)? I've been burned trying to get the FFC _Crypto class to work across different versions of Windows, re: different flavors of rsaenh.dll. (I noticed that rsaenh.dll is not referenced in above code, but I'm still concerned about the same problem version dependencies).

    Thoughts?
    Malcolm

    Copyright 2001-2014 News2News, Inc. Before reproducing or distributing any data from this site please ask for an approval from its owner. Unless otherwise specified, this page is for your personal and non-commercial use. The information on this page is presented AS IS, meaning that you may use it at your own risk. Microsoft Visual FoxPro and Windows are trade marks of Microsoft Corp. All other trademarks are the property of their respective owners. 

    Privacy policy
    Credits: PHP (4.4.9), an HTML-embedded scripting language, MySQL (5.1.68), the Open Source standard SQL database, AceHTML Freeware Version 4, freeware HTML Editor of choice.   Hosted by Korax Online Inc.
    Last Topics Visited (204.236.255.69)
    9 sec.Solution: 'Extended MessageBox Library (assembly) for .NET'
    22 sec.Example: 'Basic Volume information'
    31 sec.Example: 'Opening the Page Setup dialog box to specify the attributes of a printed page'
    Google
    Advertise here!