tcoin

Currency simulator on tilde.town and other tildeboxes on tildeverse.org

Instructions to get started

1. Clone the repo.
2. Create a service user specifically for tcoin.
3. Make sure you have bash, realpath, echo, touch, mkdir, g++, head, true, base64, and cat are available.
4. Run ./ntcoin a b c d as the service user, where a, b, c and d are defined as follows:
   • a: the absolute path to the directory (without the trailing slash) where the tcoin folder containing all the users' data will be stored (i.e., the script will create the directory a/tcoin/)
   • b: the absolute path to the directory (without the trailing slash) where the tcoin and pcoin executables will be located, i.e., all users will have to have r-x permissions on b so that they can access the executables b/tcoin and b/pcoin. Please note that b/tcoin and b/pcoin will have the suid bit set. This means that when they run b/tcoin and b/pcoin, it will be with the uid of the service user (not their own uid). This is how they are able to send and receive coins only through the executables but not modify the a/tcoin/ themselves.
   • c: an integer number of tildecoins that every user starts with. This is stored in a/tcoin/base/base.txt, and for universal-basic-income-style inflation, one can modify a/tcoin/base/base.txt using a cronjob. This will increase everybody's coins in real time.
   • d: a host name (in quotation marks, e.g., d = "tilde.town") that will appear in tcoin --help.

Instructions to create program accounts

1. Run b/npcoin a as the service user in the parent directory of the tcoin folder, i.e., if the tcoin folder is in directory with absolute path x, then run cd x; b/npcoin a. Here, a is the name of the program account you want to create, and b is the absolute path to the tcoin repository that contains the npcoin script. Program accounts should start with a capital letter (e.g., My_program_account or My-program-account).
2. Create a file in the tcoin/secrets/pcoin_keys/ directory with the following name: My_program_account.txt (assuming the name of the program is My_program_account) and add the following newline-terminated line to it: <a 64-character random alphanumeric (either all lowercase, or mixed-case will also work) string>
3. The string will be the key that the program uses to access and operate its account, and must be given to the requester of the program account securely (and currently, manually). I usually use random.org to generate these 64-character strings because I don't trust pseudorandom number generators (even if they are cryptographically-secure pseudorandom number generators). Anybody who can guess a key can use that program's account.
4. Program-account creation is currently not automated because of concerns about name-squatting and similarly-named program names.