Quantum Resistant Ledger - First of its kind...

Right now QRL is trading as an ERC20 token while the final QRL is developed on testnet. It will be exchanged 1:1 at mainnet.

Upon release of mainnet, the Quantum Resistant Ledger (QRL) will be a first of its kind, future-proof post quantum value store and decentralized communication layer which tackles the threat Quantum Computing will pose cryptocurrencies. This is backed by provably secure, peer-reviewed XMSS (vs 256 ECDSA) with a deferred Quantum Proof of Stake (QPoS) system for secure staking. Also included will be:

A webwallet for a no batteries needed experience to use (just a browser like MEW)
Desktop Apps (windows, mac, linux)
gRPC with protobuf for a powerful API
PQ Ephemeral messaging layer
It's encouraged to read our whitepaper

Are quantum computers actually a threat? They are decades away aren't they?
The NSA seems to think so enough that they no longer recommend 256-P ECDSA. This is what many cryptocurrencies today use.

Modeling of when it will be a threat has been done in a paper that suggests 2027. Not included in this model is IBM's recent 50 qubit quantum computer, or Japan's upcoming release on one potentially 100x that. Quantum Computers have stuck in the 1 to 2 qubit range until 2016 when IBM released a 5 qubit computer and 10x'd that in 18 months. Modeling with old data may not tell the whole story.

Overall, one cannot always (or, one could argue, ever) predict when and where technological innovation will rapidly progress. This is especially true of emergent technology, and both blockchain and Quantum Computers would qualify as such. There is potential for an unforeseen/unpublicized advance in Quantum Computing leading to an attack on a cryptocurrency network, and the market-wide realization of the sudden vulnerability of cryptocurrencies that are based on ECDSA encryption methods. This would likely cause a "run on the banks" scenario and crash the value of many-if-not-most cryptocurrencies that were secured by ECDSA.

Can't cryptocurrencies just swap out their cryptography?
A change from ECDSA-based addresses to quantum-safe addresses would be no small fork, and would potentially require disabling active addresses for a period of time while a fork was implemented, regardless of the specific cryptocurrency. This could have significant deleterious effects on a cryptocurrency-powered blockchain network, and, as we have experienced in creating our own blockchain, could also require the changing of significant sections of the cryptocurrency's code to accommodate the new security features, drawing into question the feasibility of implementation.