ToTheBlockchain is a Twitter bot that copies tweets (text only) to the Bitcoin blockchain when anyone with a ToTheBlockchain account replies to a tweet with the hashtag #ToTheBlockchain
Bitcoin stores data on a blockchain because blockchains have properties that make digital money transmission possible without central authority.
But those same properties that make money transmission possible also make for a perfect long-term (eternal?) archival technology.
Simply reply on Twitter to any tweet with the hashtag #ToTheBlockchain
If you don't have an account, we'll reply to you on Twitter telling you to create an account so you can add your credit/debit card (writing to Bitcoin's blockchain is expensive).
If you do have an account we'll immediately copy the tweet to the Bitcoin blockchain and reply to you that it's on the blockchain.
Bitcoin allows writing very small amounts of arbitrary data (80 bytes) in the form of a single transaction output using the OP_RETURN instruction. We use OP_RETURN for metadata and P2SH outputs for 20 byte chunks of the full tweet text. See the links below for other techniques.
The use of bitcoin's blockchain to store data unrelated to bitcoin payments is a controversial subject. Many developers consider such use abusive and want to discourage it. Others view it as a demonstration of the powerful capabilities of blockchain technology and want to encourage such experimentation.
- Andreas Antonopoulos