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Write some Software

Urgent: Need a fix (or rewrite in .net) for an existing vb6 smtp utility

Looking for a dev with experience developing in .net and coding an smtp.

are having an encryption/security issue with our vb6 SMTP utility. It's a front-end for our 15-yr software, Postmaster, a contact manager and email platform. We want

to eventually re-write it's code, but cost and client update/upgrade challenges make it prohibitive right now.

Unfortunately it's hard-coded to send only via port 25, unsecured. So the current light-weight utility just runs in the background, listening for traffic (messages

being sent) on port 25 - 'localhost', intercepts the messages, encrypts them and sends them on secure to their ISP through port 465/SSL or port 587/TLS, for example.

Note: we are also evaluating for a dev to handle larger projects with Postmaster, as well, down the road.

This current little vb6 project, I think it was written in worked perfectly all the way up to Windows 8.0 but doesn't play nice with newer Microsoft

security/permission environment in 8.1, introduced in preparation for windows 10.

I can provide project files from the original mailer if needed.

Option 1: Write replacement code with the possibility of writing a .net module inside the existing vb6 framework.

Option 2: Re-write the small utility using .net with OpenSSL or possibly Python.

*.net using OpenSSL library as the base for all encryption and key manipulation operations is the safest bet.

FYI everything worked fine, with the existing utility, until the active x mailer executes. The issue begins in the [login to view URL] file with scripts using [login to view URL]

which try to save key encryption in the registry to use later for the 587/TLS or 465/SSL secure connection.

The problem seems to be right away when it tries to write the algorithm keys to the registry initially. It was also mentioned that the program tries to implement all

standard cryptography itself, and that we should utilize .net using OpenSSL library.

When it begins to process email we get these errors on indefinate loop:

Unable to verify signature!

Error 80090020:CryptSetKeyParam in [login to view URL]

Error 8009000B:CryptCreateHash in clsCrypt.Hash_SHAMDS

Error 57: CryptAcquireContext in [login to view URL]

Fatal Alert 20

Session hash appears to be compromised

Error 57: CryptGetHashParam in clsCrypt.SHA1_GetHash


The existing utility binary was uploaded.

(I can send instructions and/or project files on request)

The simply front-end GUI only adds the email authentication credentials:

• Server address:

• Port number: SSL/TLS

• Credentials: User/Pass

• Max messages sent per hour

Utility Considerations:

• Must encode RFC Compliant emails and headers.

• Multipart MIME Message Bodies (The ability to send text messages and html & text messages, both.)

• Server auth and secure auth transport layers, decoding for non ASCII messages, CR LF line break format, etc.

• Must work on 32bit and 64bit systems up to windows 10

• How and when the utility opens/run and closes.

• Charset="UTF-8", Content-Transfer-Encoding: 8bit, MIME-Version: 1.0

• Do not use X- markdowns in headers

• Must Allow email attachements

• Properly encoding e-mail headers:

From: "John Q. Smith" <xxxxxxxxxxxxxxxxxxx>

Date: Sat, 12 Jul 2003 20:07:37 -0400 EDT compliant format



Reply-To: same as from

Message ID

• Mail limit / throttle - limit messages sent per hour. Able to disconnect from the server, wait for the difference from 60 minutes reconnect and continue, till done. THE best way is to save messages Postmaster pushes out, into a temp file then read the stream from the file instead of Postmaster

Get back to me if you're experienced in this area and have a potential solution.

We have a max budget on this project at $250USD

Thanks so much!

Mark Wittkowski, Founder

Online Automation, Inc

Kemahiran: .NET, Kejuruteraan Perisian, Visual Basic

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Tentang Majikan:
( 1 ulasan ) Bismarck, United States

ID Projek: #9789151