This category lists some of the users who are participants in the Wikipedia:WikiProject Cryptography.
If you add this userbox to your userpage you get included in this category automatically:
{{User WikiProject Cryptography}}
 | This user participates in WikiProject Cryptography. |
If you don't want to use the userbox you can instead include this code at the bottom of your userpage:
[[Category:WikiProject Cryptography participants|{{PAGENAME}}]]