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Does anybody actually understand the implications of this? This press release is very light on information. What does this technology being added to Ethereum en

Does anybody actually understand the implications of this? This press release is very light on information. What does this technology being added to Ethereum enable that wasn't possible before?

chrispeel 9y ago
The elliptic curve pairings that will be added to Metropolis will enable fully anonymous transactions as in Zcash. The zk-SNARKS that Zcash uses for currency transactions can be used for a wider variety of transactions in Ethereum. The elliptic curve tech will also enable things like the BLS signatures used by Dfinity.
- ianmiers 9y ago
  As a practical note, on that curve, Zcash is about the limit in terms of complexity for what you can do practically with a SNARK. This is why ZCash is switching to a much faster construction and supporting curve which gives it a lot of room for interesting features. As Vitalik mentioned on twitter, however, that is a long way away for Ethereum. Most applications of the pairing curve operations are probably going to be signatures and the like, not SNARKs for this reason.
1ba9115454 9y ago
In short - confidential payments. A bit longer... Normally when you send a payment with crypto currencies you leave a trace in the blockchain. i.e. other people can see which address is sending how much to where. This information is required so that the transaction can be validated by all nodes. The zk-SNARK technology allows you to send a payment without revealing the who sent how much to where.
- hisabness 9y ago
  can you help me understand why this is the case? would it not be possible to map all other addresses or to monitor balances of all other addresses and infer? i think this one is over my head.
lhl 9y ago
For those interested in more details, avsa (@avsa, Alex Van de Sande, Ethereum UX guy) broke down a list of the Metropolis (Byzantium) changes a few days ago: https://www.reddit.com/r/ethereum/comments/702t95/eli5_byzantium_changes/ https://www.reddit.com/r/ethereum/comments/702t95/eli5_byzan... You can read the release notes here btw that point to the EIP and Github issues for "Precomipled contracts for modular exponetiation; elliptic curve addition, scalar multiplication and pairing" here: https://blog.ethereum.org/2017/09/14/geth-1-7-megara/ https://blog.ethereum.org/2017/09/14/geth-1-7-megara/ AFAIK there were only 4 precompiled contracts (ECDSARECOVER, SHA256, RIPEMD, and IDENTITY) so this is sort of a big deal, but I think the right way to go (being able to natively support zkSNARKs, or RingCT/RuffCT directly on ETH would be incredibly powerful. The practical implications for this particular change is being able to run private tokens directly on Ethereum (vs globally visible transactions), although AFAIK the initial zkSNARKs implementation is not currently compatible w/ ERC20 tokens ATM.
mhluongo 9y ago
Just wrote a blog post about this. You can use SNARKs verification for data privacy https://medium.com/@mhluongo/zero-knowledge-proofs-zcash-and-ethereum-f6d89fa7cba8 https://medium.com/@mhluongo/zero-knowledge-proofs-zcash-and...

Does anybody actually understand the implications of this? This press release is very light on information. What does this technology being added to Ethereum enable that wasn't possible before?

chrispeel 9y ago

The elliptic curve pairings that will be added to Metropolis will enable fully anonymous transactions as in Zcash. The zk-SNARKS that Zcash uses for currency transactions can be used for a wider variety of transactions in Ethereum. The elliptic curve tech will also enable things like the BLS signatures used by Dfinity.

ianmiers 9y ago
As a practical note, on that curve, Zcash is about the limit in terms of complexity for what you can do practically with a SNARK. This is why ZCash is switching to a much faster construction and supporting curve which gives it a lot of room for interesting features. As Vitalik mentioned on twitter, however, that is a long way away for Ethereum. Most applications of the pairing curve operations are probably going to be signatures and the like, not SNARKs for this reason.

1ba9115454 9y ago

In short - confidential payments. A bit longer... Normally when you send a payment with crypto currencies you leave a trace in the blockchain. i.e. other people can see which address is sending how much to where. This information is required so that the transaction can be validated by all nodes. The zk-SNARK technology allows you to send a payment without revealing the who sent how much to where.

hisabness 9y ago
can you help me understand why this is the case? would it not be possible to map all other addresses or to monitor balances of all other addresses and infer? i think this one is over my head.

lhl 9y ago

For those interested in more details, avsa (@avsa, Alex Van de Sande, Ethereum UX guy) broke down a list of the Metropolis (Byzantium) changes a few days ago: https://www.reddit.com/r/ethereum/comments/702t95/eli5_byzantium_changes/ https://www.reddit.com/r/ethereum/comments/702t95/eli5_byzan... You can read the release notes here btw that point to the EIP and Github issues for "Precomipled contracts for modular exponetiation; elliptic curve addition, scalar multiplication and pairing" here: https://blog.ethereum.org/2017/09/14/geth-1-7-megara/ https://blog.ethereum.org/2017/09/14/geth-1-7-megara/ AFAIK there were only 4 precompiled contracts (ECDSARECOVER, SHA256, RIPEMD, and IDENTITY) so this is sort of a big deal, but I think the right way to go (being able to natively support zkSNARKs, or RingCT/RuffCT directly on ETH would be incredibly powerful. The practical implications for this particular change is being able to run private tokens directly on Ethereum (vs globally visible transactions), although AFAIK the initial zkSNARKs implementation is not currently compatible w/ ERC20 tokens ATM.

mhluongo 9y ago

Just wrote a blog post about this. You can use SNARKs verification for data privacy https://medium.com/@mhluongo/zero-knowledge-proofs-zcash-and-ethereum-f6d89fa7cba8 https://medium.com/@mhluongo/zero-knowledge-proofs-zcash-and...