I built this originally for use with a client -- but there's nothing client specific in here. This is a straightforward implementation of the SHA1 hash algorithm. SHA1 is commonly used for credential hashing and token validation in single sign-on applications. When given a string data, it returns a specific hash value, which will be the same every time for the same input string, but which cannot be "decrypted" back to the original. The hashed value is much smaller and easier to store. Hashed values are also the proper way to store passwords. SHA1 isn't the newest, best, or most secure -- it can be vulnerable to dictionary attacks if common passwords are used. It is, however, excellent for use as a unique key or validation hash.

In Lotuscript, it's actually faster to call evaluate(|@password("sourcestring")|) for a similar result, however SHA1 is commonly available for other platforms and thus makes a more useful hash when passing tokens to other systems.

The read-me and license part is listed below, but what you really want is the lss file.

NCT_SHA1_PROVIDER_CLASS.LSS NCT1_SHA1_PROVIDER_CLASS.LSS

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README
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This is just a straightforward implementation of SHA-1, adapted for use in
Lotuscript by Andrew Pollack, Northern Collaborative Technologies. You can
contact me by email at andrewp@thenorth.com or by way of my blog at
http://www.thenorth.com/apblog

For my implementation, the simplest way to use the code is as follows:

dim o as new NCT_SHA1_PROVIDER
hashvalue = o.sha1("", SourceTextString)

I choose to make use of a class simply to keep all the original code together in a
single unit that would not likely have any namespace clashes with anyone's
existing code.
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License Information:
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Since the SHA1 algorithm is itself in the public domain, John Taylor (who's code
I have adapted here) released his work to the public domain as well. Following
suit, I'm doing the same.

So far as I, Andrew Pollack, am concerned, I am releasing my part of the work into
the public domain, and officially renounce all rights to it. I also renounce all
liability from it. If you use it and something breaks, you own all the broken bits.

I would appreciate - as I'm sure John Taylor would as well, if you would keep a
reference to the previous work an your own implementation and distribution as a
matter of courtesy.

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The source I started from was distributed by John Taylor, of Taylor Electronics
Services via his web site at:

http://www.tayloredge.com/utilities/vbapps/SHA1_VBSource.txt

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Mr. Taylor includes this message with his source:

Since only creative works are copyrightable, this code is in the public domain.

The essential function is simply to call sha1("", "textdata") and get back a hash
string as 40 hex characters
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