What is bitsig?
Bitsig utilizes the Bitcoin blockchain to provide proof of existence and timestamping for text and documents without destroying bitcoin or adding unnecessary data to the blockchain. By sending a small amount of bitcoin to the generated address, you prove that your text or document existed at that time. If you choose to sign your text or document with PGP or other authentication methods, you can even prove who created it.

How does bitsig work?
Bitsig has two primary modes of operation:

Direct text input
Any text entered into the text box can be used to generate a Bitcoin address using the brainwallet process. Sending any amount of bitcoin to the generated address will create a transaction on the bitcoin network. Once the transaction is confirmed it will remain permanently in the blockchain for future reference.

File hash
Instead of entering text, you can drop any file into the text box and your browser will perform an SHA256 hash on the file to derive a checksum. This checksum will be used to generate a Bitcoin address. The file hashing takes place in your browser, and never gets sent to or stored on our servers.

There is no limit to the size of text and files that can be timestamped, however, bitsig will only store and display up to 10 kB of data. If your data exceeds 10 kB, be sure to keep a copy of it for future validation.

Sending any amount of bitcoin to the generated address creates an immutable and irrefutable record that a statement was made, or that a document existed at a given time, using the trustless, decentralized Bitcoin network. Once the information is confirmed by the Bitcoin network it cannot be altered. Any change to the content would generate a new address and require a new transaction to place it on the blockchain.

What are the uses for bitsig?
Contracts, timestamping, document verification, proof of existence, voting, advertising, public announcements... the possibilities are endless.

How much does it cost?
As little as possible. Even the smallest amount of bitcoin (one satoshi or 0.00000001 btc) is sufficient to prove existence on the blockchain. Just don't forget to include a miner fee when sending your transaction to encourage swift processing (most wallets do this automatically).

What happens to the bitcoin that gets sent?
The private key can be derived from the text that you timestamped, so the bitcoin is available to anyone who wants to claim it. It doesn't matter if the bitcoin gets taken because the fact that any transaction was made to that address is sufficient to prove it existed at the time of the initial deposit.

Why should I use bitsig?
Bitcoin is designed to be trustless; nothing is happening on this website that you couldn't do on your own. We just aim to simplify the process for your convenience, and provide a public log of all transactions that take place on our website. The bitcoin you send to the generated address goes directly to that address, not to bitsig. Our service is free, and the source code is readily available. No personal data is ever collected or shared.

What if bitsig goes down?
Your proof of existence is stored on the blockchain and is not dependent on bitsig.

Doesn't this bloat the blockchain with useless data?
No more than any other standard transaction. This is very different from services that utilize the OP_RETURN output to store data, which quickly adds to the size of the blockchain as those transactions include additional bytes of data. We also do not destroy bitcoin by sending them to an unspendable address.

It is inevitable that the blockchain will be used for applications other than currency. We aim to make one of the blockchain's most powerful features easy to use and accessible to everyone.

How do I report a problem?
Please write to routman@protonmail.com if you run into any trouble.

How can I help?
We would love to hear your feedback and suggestions. And of course, donations are always appreciated.