The Parity client is an implementation of Ethereum blockchain technology allowing the user to store, send and receive tokens as well as to create distributed apps (Dapps).
The Parity client powers much of the infrastructure of the public Ethereum network and is used by companies and users alike. It is the second most popular Ethereum client.
Parity tutes itself as "the fastest and most secure way of interacting with the Ethereum blockchain".
The client had security issues in the past.
On 19th of July a multi-sig issue has been found which allows malicious users to exploit it.
On November 7, 2017, Parity has been hacked and 500.000 Ethereum vanished.