Add-on Single-use embeddable serial keys


We need a way to occasionally distribute various keys (mostly game keys) to our users. They should have a form of post-embeddable blocks, similar to spoiler tags. The key/serial number is hidden when viewed and revealed only when clicked but only to a user who clicks (reveals) it first, thus claiming it. When the key is claimed it is marked as such (is no longer active) for other users, but the original claimant still sees the serial it claimed - it is permanently assigned to his account, and specific key occurrence (multiple keys can be used in a single post, and the user can claim more than one in the post).

They could have a form of the following BB code:


Which initially shows as a button with text:

[this key has not been claimed yet]

to everyone, but when claimed, it could be changed into a simple text:

[this key has been already claimed]

for everyone but the claimant, but for him to show the key:


Looking forward to hearing from interested developers!