Secure Dice

Brandon Blackmoor
Free (GPL) (source)

RPG Library Secure Dice is a free online dice roller which will generate random numbers, generate a MD5 checksum of the results, and email those results to the email address(es) you specify.

950721 dice rolled since 2005-11-06.

Roll d , and
Roll this set of dice times.
Send the signed results of this roll to yourself:
and the GM:
with this subject:

You can pre-populate these values by adding them to the URL. The first value you set must be preceded with a question mark (?). Values after the first must be preceded by an ampersand (&). Here are permitted options, and their allowed values:

dq=	dice quantity: any integer from 1 to 20
ds=	dice sides: 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 18, 20, 25, 30, 100
dm=	dice modifier: any integer from -20 to 20 (for numbers greater than -1, do not include a plus sign)
dd=	dice drop: lowest, none, highest
dt=	dice sets: any integer from 1 to 20
to=	Your email address: one valid email address
cc=	GM's email address: one valid email address
sub=	email subject: A brief message, with "%20" instead of spaces (example: This%20is%20a%20test)

Here is an example of a URL which pre-sets some of these values:

http://www.rpglibrary.org/software/securedice/?dq=7&ds=4&dt=5&to=bblackmoor@blackgate.net&sub=This%20is%20a%20test

Verify your results - email from the dice server includes a MD5 checksum which can be used to verify that the dice roll sent to you has not been modified. You can type the checksum into the verification page to ensure that the dice results are genuine.

Never accept a roll sent from anyone other than the RPG Library server. If the other player forgot to include your email address when generating the dice roll, ask them to roll again: it's the only way to be sure that they sent you the results of a single die roll, rather than the best of many rolls.