Welcome to BitVM Online

To run the bitvm there are seven steps:

Pick a program
Act as the prover to commit to a certain output
Send money to the program
Act as the prover to share which "inputs" make the code produce the expected output
Act as the verifier to check if the code, with those inputs, produces the expected output
If it does, act as the prover to take the money after a timelock
Otherwise, act as the verifier to take the money by producing the error

Pick a program you want to run

Zero checker

In this program, the prover must share a string of numbers with the verifier within a time limit, but not before making one of two promises: the string will only be 0s, or the string will *not* only be zeros. The verifier can take the prover's money if the promise is broken.

Size checker

In this program, the prover must share two numbers with the verifier within a time limit, but not before making one of two promises: (1) the first number will be bigger than the second number, or (2) the first number will not be bigger than the second number. The verifier can take the prover's money if the promise is broken.

Addition

In this program, the prover must share a number with the verifier, then make a promise: within a time limit, they will share two numbers that sum to the original number. The verifier can take the prover's money if the promise is broken.

Adder (8-bit)

Shifter

In this program, the prover must share a number with the verifier, then make a promise: within a time limit, they will share a number that when shifted will become the original number. The verifier can take the prover's money if the promise is broken.

SHA256

In this program, the prover must share a hash with the verifier, then make a promise: within a time limit, they will share the preimage corresponding to that hash. The verifier can take the prover's money if the promise is broken.

This is a toy implementation, don't expect much.
I wrote the VM in about 200 lines of javascript which means it barely works.
It breaks if you put a program with more than about 3000 logic gates in it. Help me write a better one!
The whitepaper talks about using "binary search" in a challenge to find the shortest path to prove your counterparty is equivocating. I don't know how to program a binary search so I just didn't. Instead, if you challenge the prover, he has to *prove the entire computation himself, all on chain.* Which is very dumb, and expensive. But I wasn't trying to make it the smart way, I was trying to make it the easy way. Help me improve it!
If Paul doesn't send Vicky the data he promised, she is technically able to take his money after a 10 block timelock, but I didn't automatically give her a transaction for this like I did for Paul. So she's just out of luck til I do that. (Or you can figure out how to write bitcoin transactions manually and do it yourself.)
Paul doesn't make Vicky pay him, or even check if her signatures on the presigned transactions are correct. He just yolos his money right into the bitvm address with no checks or balances, so Vicky can easily steal from him by just immediately moving it into the challenge address without presigning the transaction that lets him take it out again. Fixing that is on my todo list. So is having Vicky pay Paul for the computation.
There are a bunch of other caveats but whatever, it technically works! I'm really looking forward to testing more functions with this. Bitcoin can run *anything* guys! Let's write some functions for it!

Zero checker

In this demo you will play as Paul, the prover. The first step is to open up the page where Vicky -- the verifier -- will verify your program, and copy her public key, and paste it here

Visit Vicky's page: Vicky page

Enter Vicky's public key

Time to make a promise to Vicky! Will your string be all 0s or not all zeros?

Click ok when you've sent the promise file to Vicky

Enter the bitcoin address where you want your money to go when you get it back:

Also, it's time to validate that you and Vicky generated the same bitcoin addresses. Do all of these match what Vicky got? (Note: don't send any money to them yet)

Also, send *PRECISELY* 10,000 sats to the following address to start the contract (if you send the wrong amount it will not work):

Asking for txid and vout in 3 seconds

Broadcast the following transaction to finalize the contract:

What string do you want to reveal to Vicky? Remember, you promised and she can take your money if you lie

Add this many more characters: 64

Note that your string must only contain 0s and 1s

Addition

In this demo you will play as Paul, the prover. The first step is to open up the page where Vicky -- the verifier -- will verify your program, and copy her public key, and paste it here

Visit Vicky's page: Vicky page

Enter Vicky's public key

Time to make a promise to Vicky! Enter a number. Later, you will need to enter two numbers that sum to this number.

Click ok when you've sent the promise file to Vicky

Enter the bitcoin address where you want your money to go when you get it back:

Hint: if you don't have a testnet wallet, you can just send it to a testnet faucet at this address:

tb1q349k20q0yft6knyss5cdpcrgmg30taxyt5ggse

Also, it's time to validate that you and Vicky generated the same bitcoin addresses. Do all of these match what Vicky got? (Note: don't send any money to them yet)

Send *PRECISELY* 10,000 sats to the following address to start the contract (if you send the wrong amount it will not work):

Asking for txid and vout in 3 seconds

Broadcast the following transaction to finalize the contract:

What two numbers do you want to reveal to Vicky? Remember, you promised they would add up to loading... and she can take your money if you lie

Enter your first number

Enter your second number

Adder (8-bit)

In this demo you will play as Paul, the prover. The first step is to open up the page where Vicky -- the verifier -- will verify your program, and copy her public key, and paste it here

Visit Vicky's page: Vicky page

Enter Vicky's public key

Time to make a promise to Vicky! Enter a number. Later, you will need to enter two numbers that sum to this number.

Click ok when you've sent the promise file to Vicky

Enter the bitcoin address where you want your money to go when you get it back:

Hint: if you don't have a testnet wallet, you can just send it to a testnet faucet at this address:

tb1q349k20q0yft6knyss5cdpcrgmg30taxyt5ggse

Also, it's time to validate that you and Vicky generated the same bitcoin addresses. Do all of these match what Vicky got? (Note: don't send any money to them yet)

Send *PRECISELY* 10,000 sats to the following address to start the contract (if you send the wrong amount it will not work):

Asking for txid and vout in 3 seconds

Broadcast the following transaction to finalize the contract:

What two numbers do you want to reveal to Vicky? Remember, you promised they would add up to loading... and she can take your money if you lie

Enter your first number

Enter your second number

Size checker

In this demo you will play as Paul, the prover. The first step is to open up the page where Vicky -- the verifier -- will verify your program, and copy her public key, and paste it here

Visit Vicky's page: Vicky page

Enter Vicky's public key

Time to make a promise to Vicky! Enter a number and say whether it is bigger than a number you'll send Vicky later.

Will the number you just entered be bigger than the number you'll send Vicky later?

Click ok when you've sent the promise file to Vicky

Enter the bitcoin address where you want your money to go when you get it back:

Hint: if you don't have a testnet wallet, you can just send it to a testnet faucet at this address:

tb1q349k20q0yft6knyss5cdpcrgmg30taxyt5ggse

Also, it's time to validate that you and Vicky generated the same bitcoin addresses. Do all of these match what Vicky got? (Note: don't send any money to them yet)

Send *PRECISELY* 10,000 sats to the following address to start the contract (if you send the wrong amount it will not work):

Asking for txid and vout in 3 seconds

Broadcast the following transaction to finalize the contract:

What number do you want to reveal to Vicky? Remember, you promised Vicky your original number (loading...) would be "loading..." than the number you're about to enter. She can take your money if you lie.

Enter your number of comparison

Shifter

In this demo you will play as Paul, the prover. The first step is to open up the page where Vicky -- the verifier -- will verify your program, and copy her public key, and paste it here

Visit Vicky's page: Vicky page

Enter Vicky's public key

Time to make a promise to Vicky! Enter a number. Later, you will need to enter a number that after shifting becomes this number that you are about to enter.

Click ok when you've sent the promise file to Vicky

Enter the bitcoin address where you want your money to go when you get it back:

Hint: if you don't have a testnet wallet, you can just send it to a testnet faucet at this address:

tb1q349k20q0yft6knyss5cdpcrgmg30taxyt5ggse

Also, it's time to validate that you and Vicky generated the same bitcoin addresses. Do all of these match what Vicky got? (Note: don't send any money to them yet)

Send *PRECISELY* 10,000 sats to the following address to start the contract (if you send the wrong amount it will not work):

Asking for txid and vout in 3 seconds

Broadcast the following transaction to finalize the contract:

What number do you want to reveal to Vicky? Remember, you promised it would become loading... after it gets shifted. She can take your money if you lie

Enter your number

Shift right or left?

SHA256

In this demo you will play as Paul, the prover. The first step is to open up the page where Vicky -- the verifier -- will verify your program, and copy her public key, and paste it here

Visit Vicky's page: Vicky page

Enter Vicky's public key

Time to make a promise to Vicky!
Enter an SHA256 hash in hex format:
(you can use this online tool to generate one)

Click ok when you've sent the promise file to Vicky

Enter the bitcoin address where you want your money to go when you get it back:

Hint: if you don't have a testnet wallet, you can just send it to a testnet faucet at this address:

tb1q349k20q0yft6knyss5cdpcrgmg30taxyt5ggse

Also, it's time to validate that you and Vicky generated the same bitcoin addresses. Do all of these match what Vicky got? (Note: don't send any money to them yet)

Send *PRECISELY* 10,000 sats to the following address to start the contract (if you send the wrong amount it will not work):

Asking for txid and vout in 3 seconds

Broadcast the following transaction to finalize the contract:

Now enter the preimage corresponding to the hash you promised to Vicky (loading...). She can take your money if you lie.

Enter the preimage here: