IMO, it's SmartContract + IPFS. McAfee could have written his own DMS DAPP, then he could make it do anything he wanted. What I don't understand is why the slow churning to do the drop. Appears to increase the risk of it being stopped.
https://www.dapp.com/article/what-are-smart-contracts/
Ethereum’s Smart Contract
What we just described is the Smart Contract for Bitcoin, which was designed to keep a detailed record of who owns what or to be used as a currency that eliminates the need for third-parties (like banks and governments) when moving large amounts of money.
Ethereum, on the other hand, was explicitly designed with the purpose of using Smart Contracts differently. The creator of Ethereum, Vitalik Buterin, adapted blockchain in a way geared to allow developers to add functions in the Smart Contract that supported their (the developers’) various needs. Coding a Smart Contract was very difficult as the Ethereum network reads them in Bytecode or, simply put, in ones and zeros. To make it easier for developers to create ever more complex Smart Contracts, the programming language "Solidity" was created by Buterin. Developers using Solidity, which is similar to JavaScript, now had the means to design their Smart Contracts in the way they wanted.
With these capabilities, Ethereum became a Virtual Machine that could essentially provide functions that can run software, websites, and apps on the decentralized Ethereum network. Ultimately, the goal of Ethereum is to reach "Turing Completeness," which in this case means being able to simulate the capabilities of a computer on the decentralized Ethereum network.
Applying its Capability
If you want to try out Ethereum's capabilities, do check out the dapps on our website. Most interesting is the manner in which Smart Contracts may be applied to areas related specifically to bureaucratically-centered institutions. Another application concerns your personal bureaucratic documents—from your birth certificate to your driving license. Imagine if every single legal document pertaining to you was stored in a decentralized network and that if you needed a copy of any of them all you had to do was send a request after confirming your identity, whereupon you would be getting the requested document instantly. Such a system would speed up otherwise very slow and cumbersome processes.
Taking this a step further would be to code the Smart Contract to automatically update all legal documents when buying a house, getting insurance, or when paying your taxes. Since everything from transactions to ownership is transparent and incorruptible, this would reduce tax evasion and smoothly create a more effortless way of living and governing.
Even Amazon, for instance, could potentially get in on this by automating everything and using Smart Contracts. Smart Contracts would ensure that the transaction was made, the item was sent from the warehouse, and guarantee the package had arrived at its destination. It might sound like science fiction, but Amazon is already using drones for maintaining warehouse stock and even for deliveries.