I have never quite understood how companies just have a single landing page with no publically available product or service (as it seems) and still get bought for several hundred millions.
Multi-party computation (MPC) enables you to participate in public key cryptography with shares ("parts") of a private key divided between multiple participants from the get-go, i.e. without ever having the private key in memory at any point in time.
So for example, if you divide the shares between mobile devices and servers then all of them would need to communicate with one another to sign a message without any of them knowing the private key. There are variants (e.g. 2 out of N, etc.), but that's the gist of it.
Connecting it to cryptocurrency wallets, you can then use this scheme to create accounts where the control is shared between multiple devices and "mathematically" it doesn't matter then if one of the devices is compromised - it could never do anything on its own.
Curv provides MPC-based crypto custody solution wi. I'll be over-simplifying but they allow private keys that protect large sums of cryptocurrencies to be split in encrypted portions called 'shares'. These shares are both created and used in a fully distributed manner (just like threshold signing / or 'multi-sig'). You generally define a threshold 'm' out of 'n' that's mathematically required to get a valid cryptographic signature.
An attacker would need to compromise a sufficient quorum of these keys simultaneously in order to sign blockchain transactions that would extract the funds somewhere else. As you can imagine, the complexity of such attack is highly correlated (and actually tends to grow exponentially due to several factors) to the quorum threshold 'm'.
Curv seems to allow financial institutions and all kind of institutional investors to create the shares, manage them and use them securely to sign transactions.
The argument they provide which makes little sense to me is that there is no 'private key'. They just seem to play with jargon as the shares are pretty much equivalent to individual keys in a multi-sig system, or at least hold the same power and have same results in compromise scenarios.
Does these kind of solutions work for every cryptocurrencies? For example does is support Bitcoin? Or is this something that needs some kind of smart contract like those provided by Ethereum?
And another question: what about optionally fully anonymous transaction as in ZCash, does the scheme work to sign tx done using ZK proofs too? Or fully anonymous ones, like David Chaum's upcoming "xx coin"?
The only blockchain-native mechanism that's getting more popular but unfortunately not supported everywhere yet is multi-sig. I consider multi-sig equivalent in term of security to MPC in practice. Bitcoin and many blockchains supports multi-sig addresses (ethereum does this through smart contracts but is still very much a native feature).
I am sure there are some web designers on here, curious if the simplification, minimalist design is a trending theme, I feel it is.