View Full Version : flexlm 11.8 known pri/pub key

January 18th, 2013, 08:21
Knowing the private/public keys is it possible to generate license for flexlm 11.8?
I have the 11.4 sdk

January 18th, 2013, 09:16
without problem

January 18th, 2013, 11:39
thanks FoxB for your reply
Would you give me more information?
What other info do i need? I have VENDOR_KEY(1-5), TRL_KEY(1-2) and pri/pub keys but no seed. Is it enough?
in the sdk files, where should i put the private key?

January 18th, 2013, 11:44
well, explain more about your "pri/pub keys"
what is?

January 18th, 2013, 11:57
i found a utility which is called "Generic ECC pubkey replacer" developed by tanker
it will replace target application's ECC public key with a known one.
Then you can use a known ECC private key to generate a valid license.
The question is having this private key how to build the lmcrypt,exe?
vendor keys are known

January 18th, 2013, 12:09
i'm not use this way, sorry.

January 25th, 2013, 12:09

This is the approach I've been using for the last 5 years or so. I had planned to write a quick tutorial showing the method I'm using, but essentially it goes something like this.

1. Build a lmcrypt.exe for target vendor using your own LM_SEEDS.
2. Dig out the 3 public keys from generated lmcrypt. They are 0x10/0x16 & 0X1F bytes in length as I recall.
3. Replace public keys in target with those from your lmcrypt.
4. Licenses can now be generated.

This is an over-simplification of the process, the public keys are rebuilt byte by byte at run-time so digging out all of the bytes to patch is kind of boring, (I wrote a program to do it). There are some other pitfalls I've seen, some targets have multiple public keys, you can also patch only the public key length your actually interested in, so if the program uses short ECC keys then only the shortest key needs patching.

Best regards,


January 26th, 2013, 12:39
Thanks CrackZ for your response.

I'm trying to follow your steps, but step 2 is a complicated for me
Question 1) AFAIK there should be one private key and 2 public keys. or do we have 3 pub keys?
Question 2) I don't really know how to start digging out the keys. Would you please give me a clue?

I appreciate your help in advance
Also awaiting a full tutorial from you on the subject. This will makes the life much easier ;-)

January 26th, 2013, 12:49
dear CrackZ!
instead of full tutorial,
i awaiting a from you 1 free Ice-cream!

January 26th, 2013, 15:07
Can you please describe a little about (3).. How to detect those bytes to be changed.

Best Regards and Thanks