Re: Remote licensing system

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Hi,I don't see a question in your post. I'm guessing you want to know if it
will work. The dallas chip will work fine, and gives you some extra non
volatile memory. An automated system using rs232 port will cost a lot to
implement, it just depends on how many customers you have.

Re: Remote licensing system
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A simple scheme (hardly hacker-proof):
Customer provides serial number.
Internal ID# is extracted from a list using serial number.
XOR a multi-bit feature code with the internal ID# = your key

By not revealing the internal ID#, it's harder for someone to observe
patterns in the keys, particularly a reseller who sees a lot of them.
The step below would complicate enough that S/N and ID# could be the
same value.

Some complicators:
Make only some of the feature code bits valid (say, 4 bits, distributed
across the key), and make the rest of the bits random before the XOR
step when the key is genned.  Again, thwarts obvious patterns.  Simply
AND in the device to filter them out after XOR.

The key needs to be long enough to thwart sequential keying attempts.
With 8 digits, I can just code something that steps through all the
combinations and activates all the features.  Of course, you could have
some land mine codes that lockout the device for factory reset. :-)

Any danger of getting stiffed on payment?  If so, key immediately with
an expiring key (time, uses) that gives enough time for funds to clear,
when you re-issue a permanent key.

Re: Remote licensing system
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Embedded feature upgrades are a really interesting issue.

My company has found that (at least in our products) customers will
rarely purchase software upgradeable features after the initial sale
of the product.
They will although purchase a higher end product incorporating a
feature for fear of possibly needing the feature later, if no upgrade
is possible.
They also don't feel they should have to pay for a feature that is
just a software difference, or just a change in code. But if that
change is a special memory card with that software on it, it will be
accepted (They need something tangible).
In my industry it's interesting that the embedded market has not made
the jump that the general software industry has working at for years.

Any others see this?


Re: Remote licensing system
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I'm reminded of a story from many years back... supposedly when IBM
customers bought the 10MB to 20MB mainframe disk upgrade, the
"installation" consisted of a technician removing the set-screw that
kept the head from travelling the full range.  I imagine there was a
little more to it, but humerous nonetheless.

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Very interesting!

We've considered keys for metered usage or site-specific licensing, but
not for feature enablement.  Instead, different versions of the product
will be available from the factory (as the product evolves), with
factory upgrades available (new firmware, faceplates, and labeling).
Like a trade-in, but without the leftover "used" gear".  We're planning
to support field firmware upgrades, but only for bug-fixes.

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Interesting logic to consider.  I have a similar example.

We're developing a piece of network test equipment; something that would
have as likely an audience amongst consultants (read: mobile) as
corporations (fixed installation).  Curiously, we found market
perception to give greater value to a large rack-mount version than a
lightweight handheld version - by a factor of 10+.  We expected the
opposite, but to a lesser extreme.  It pays to do market research.

So, we'll be selling only a 1U rack-mount version in a steel case (maybe
with some lead weights thrown in for "added value" :-).  All for a 4x6"
PCB.  In the end, it's likely to be better for business anyway because
instead of consultants bringing their own portable tools to the job,
they are more likely to install units the customer purchases
themselves.  We hope. ;-)

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Yes, or perhaps requiring a factory return for the upgrade (for
higher-cost, lower-volume goods).  It seems that removing the mystery
around the product (by making it customer-servicable) diminishes some of
the respect in many cases (and perhaps value perception).

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I can see how this might occur.  Perception is that I've bought the
hardware, and now I should be able to use it to the fullest (i.e., the
software is an "entitlement").  However, when buying software, the
perception is more clearly one of buying functionality, so there might
be less perceived entitlement to new unpaid features.

Re: Remote licensing system

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Wouldn't surprise me. I remember a tape drive speed upgrade which
consisted of changing pulleys and belts.

Al Balmer
Balmer Consulting
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Re: Remote licensing system
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Many thanks for all the responses, and for the insight into how users see
firmware-enabled upgrades to equipment - very telling! I am guessing we will
experience a similar reaction ;)

In pratice, we might make the user return the unit to their reseller so they
can perform the upgrade - this might make the cost seem more acceptable to
the customer(?)

Best regards,


Re: Remote licensing system
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Thanks for your advice, Lewin. Yes, in the past RS232 for us has been
amazingly troublesome for such a simple interface, whether it be due to
Windows version/laptop ports etc. We do have an up/down/enter kind of keypad
on the unit and so I'll try to implement it via that. It turns out I will
also need to implement an RS232 method, since we now intend to ship some
types of unit without any keypad at all.


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