30.11.2017 – Launch of second prototype

The second version of our prototype is now live. It now uses the Ethereum blockchain for storing cryptographic proof-of-reception for blockchain-certified documents, and introduces Yubikeys as a new mechanism for electronically signing the reception receipts. We believe these two technologies fit perfectly with the zipper instant messaging platform, so that it can offer a truly modern alternative to physical recommended letters in a much cheaper and convenient format.