Firmware (device) support | Trezor One, Trezor Model T |
Available in Trezor Wallet | Yes |
Third-party Wallets | Electrum, Mycelium, Exodus |
Bitcoin has several predecessors which had the same goal but weren't successful. Most of them had an impact on bitcoin technology and are used in it.
B-money was an early proposal created by Wei Dai for an "anonymous, distributed electronic cash system," according to his essay published in November, 1998. Satoshi Nakamoto referenced b-money when creating Bitcoin.
Hashcash is a proof-of-work system used to limit email spam and denial-of-service attacks, and it is also used in bitcoin (and other cryptocurrencies) as part of the mining algorithm. Hashcash was proposed in 1997 by Adam Back.
Nick Szabo designed Bitgold in 1998. It is a mechanism for a decentralized digital currency he called "bit gold". Bitgold was never implemented but has been called "a direct precursor to the Bitcoin architecture. In bitgold structure, a participant would dedicate computer power to solving cryptographic puzzles.
Some other technology innovations had a big impact on creating bitcoin, such as the design of a secure timestamping service with minimal trust requirements from 1999, Merkle's Protocols for public key cryptosystems from 1980, and more.
A blockchain is a shared database secured by cryptography, which stores all the bitcoin transactions with timestamps that have been updated since its beginning. It is possible to distinguish it from the classic database with its immutability - it is not possible to change data already stored in it - and decentralization - the database is stored in many locations in the world so its accuracy is easy to audit. Block creation also allows bitcoin software to determine when a particular bitcoin was spent, which is needed to prevent double-spending.
A proof of work is a piece of data which is difficult (costly, time-consuming) to produce but easy for others to verify, and which satisfies certain requirements. Producing a proof of work can be a random process with low probability so that a lot of trial and error is required on average before a valid proof of work is generated. Bitcoin uses the Hashcash proof of work system. Hashcash proofs of work are used in bitcoin for block generation. In order for a block to be accepted by network participants, miners must complete a proof of work which covers all of the data in the block. The difficulty of this work is adjusted so as to limit the rate at which new blocks can be generated by the network to one every 10 minutes.
Mining is a record-keeping service done through the use of computer processing power. Miners keep the blockchain consistent, complete, and unalterable by repeatedly grouping newly broadcast transactions into a block, which is then broadcast to the network and verified by recipient nodes. Each block contains an SHA-256 cryptographic hash of the previous block, thus linking it to the previous block and giving the blockchain its name.
The successful miner who finds the new block is rewarded with newly created bitcoins and transaction fees. For every block new bitcoins are created, but this reward decreases in time in a previously determined process called bitcoin halving. Eventually, the reward will decrease to zero, and the limit of 21 million bitcoins will be reached in 2140.