https://github.com/tendermint/tendermint/wiki/Byzantine-Cons...
There's a lot of great innovations in Bitcoin. One of the primary reasons why it's exciting, is that it's the first widely deployed BFT ledger. Tendermint uses a different BFT algorithm that doesn't use mining.
Raft and Paxos aren't BFT, btw. As of 2012 there still weren't good implementations of PBFT/BFT middleware. http://cgi.di.uoa.gr/~mema/publications/middleware-2012.pdf . Tendermint is that middleware.
Here's a post on why Tendermint ledgers should be called blockchains:
https://news.ycombinator.com/item?id=10847136
A lot of people say that blockchains aren't blockchains without PoW. It's not surprising that people are saying this... there's been a ton of phony consensus algorithms that purport to not use PoW mining. Tendermint is different.
A fault-tolerant consensus algorithm is a consensus algorithm that can tolerate failure of any nodes (e.g. miners or validators). By failure, I'm referring to fail-stop failures, where a miner or validator crashes or goes offline. The key metric for fault-tolerant consensus algorithms is the threshold for how many failures the system can tolerate. For example, Raft is a fault-tolerant consensus algorithm can tolerate up to 49.99% of node failures.
A Byzantine fault-tolerant consensus algorithm is a fault-tolerant consensus algorithm that can tolerate not just fail-stop failures, but arbitrary failures. For example, one or more nodes that get hacked by a malicious hacker might be coordinated to subvert consensus from within. Bitcoin is exciting because it can tolerate such attacks from within (e.g. any miner) to a significant degree. Tendermint is similar, except it doesn't require significant energy expenditure for its security.
Proof-of-Stake was a family of early consensus algorithms from cryptocurrency projects that don't use PoW mining. A lot of them are terrible and suffered from the "nothing at stake" problem. For a while, the Tendermint project had been using collateral bonds to ensure that there is actually "something at stake". But Tendermit is more general than that. You can have stake with collateral posted on-or-off-chain, or, you don't need to use collateral at all. It all depends on what you're trying to build.
If you want a standalone cryptocurrency blockchain, you'll want in-chain collateral with bond deposits. But different blockchains have different requirements, so posting collateral to put something at stake may not be one of them.
Personally I think we should just avoid the term "proof of stake".
See ErisIndustries using Tendermint for ErisDB: https://github.com/eris-ltd/eris-db/blob/master/erisdb/serve...
Actually, we wrote the Ethereum virtual machine implementation that they're using. We're moving away from the EVM though, because the TMSP architecture allows for easier native-application development.
http://github.com/tendermint/tmsp
If you want proof on the security of the Tendermint consensus algorithm, it's in the Github wiki.
To my understanding, the expected future state of Bitcoin is that the role currently filled by miners will be replaced by transaction processors who take a fee to do the work.
Block chain is a wheel.... guess what, wheels have uses far beyond the Pharaoh's war chariots. Like, you know, bicycles and automobiles. Stop conflating block chain and crypto-currency.
You can't just blockchain all the things and expect all the costs that are part of the current system to disappear.
http://www.economist.com/news/leaders/21677198-technology-be...