Support for offline licensing

[prarshah]

If we use this then the same license can be validated on multiple machines, is there any other way to overcome this using license3j?
Thank you in advance.

[verhas]

You can use the UUIDCalculator class to calculate a unique UUID for the machine and you can include this calculated value in the license as a UUID feature. In case the calculated UUID and the one included in the license are not the same then the program using License3j can refuse the operation.

Note that the calculation of the UUID may not be reliable on virtual machines and it may result in different UUIDs even on the same machine some times.

[prarshah]

@verhas
Hello,
Your above-stated solution helped me, thank you.
Also, when I am validating using a public key from the program license.ok is true,
but when I send the same key as a binary feature,
( I am extracting this feature as binary to validate on client side)
the key is getting changed and shows license invalid.
Thanks in advance.

[verhas]

There are two things:

1. Check that the key is the same bit-by-bit where it works and also where you send over, package and unpackage. If they differ then there is some error in the way how you package.

2. Putting the public key to be used to check the license as a binary feature into the license itself is a total non-sense. Your user just can download License3JRepl and create its own license with its own private and public key and put its own public key into the binary feature and license the program with any parameters as they like.

[prarshah]

I know was adding the public key for POC so that I don't always have to change the file contains when I found that passing it that way doesn't get validated while the other way it does. Thanks.

[verhas]

I do not know what the problem can be. It is binary data after all. If this is the same there as in the source then it will work. I am sure you will find some simple reasons why this special way does not work.

[anaghaShotty123]

When you said:
Note that the calculation of the UUID may not be reliable on virtual machines and it may result in different UUIDs even on the same machine some times.
I guess using UUIDCalculator for first time validation only will work, then we can carry periodic validations without UUIDs

[verhas]

The first time you use the UUID Calculator to get the value to be embedded into the license as a feature. Validation uses UUIDCalculator the second, the third and so on times. And the UUIDCalculator on a virtual machine may return different values each and every time.