CryptoPPP Library Module For Processwire
Implements Steve Gibson's PPP One-Time-Pad System along with some additional helpers.
Pre-requisites
Requires OpenSSL and bcmaths PHP extension to be installed.
Version 3.1.0 changed from the, now deprecated, mcrypt library over to using OpenSSL internally.
Generating A Single Key
Simply use $key = CryptoPPP::genKeys(); or $key = CryptoPPP::genKeys(1);
Generating Multiple Keys.
If you want 2 keys you would do $keys = CryptoPPP::genKeys(2); to get them in the $keys array or do list($k1, $k2) = CryptoPPP::genKeys(2); to assign them to named variables.
Now that you have at least one key, you can use it as the basis of generating tokens or token streams.
Converting A Key Into A Token (a strings of characters).
The simplest way to convert a key into a token of a given length and using a given output alphabet is to call the
CryptoPPP::keyToToken static method. If no length or alphabet is defined a 12 character token using the default
alphabet (!#%+23456789:=?@ABCDEFGHJKLMNPRSTUVWXYZabcdefghijkmnopqrstuvwxyz) will be created from the key.
To create tokens with a format such as 'X7gM-jA9v-KtWs' where the length of the 'blocks' and the 'glue' between them are
customisable you can use the related helper method CryptoPPP::keyToTokenBlocks().
Generating A Token Sequence (a One-Time-Pad) From A Key + Sequence Number.
If your application can associate an incrementing sequence number with a key, then you can use the PPP system to
generate a One-Time-Pad (a stream of tokens.) This is simply done by passing the key, the sequence position, output
alphabet and token length to CryptoPPP::getCode(). Once your application finishes using that token from the token stream, simply increment the sequence number ready for the next usage.