Thanks for the correction, pooya. So, to rephrase: it's a good practice to not leave anything extra in stack when creating a P2SH script, and it's necessary to not leave anything extra (apart from one non-zero value) in stack when creating a P2WSH script.
For simplicity, just use OP_EQUAL instead of OP_1 OP_EQUALVERIFY.
Topic: [Quiz] Answer the Bitcoin question and earn merits! #5 (Read 653 times)
but in general, it's a good practice to not leave anything in stack, if it's possible.
You need to leave at least one item on the stack if it is a legacy script[1] and only one item if it is a witness script[2]. That item has to evaluate to true otherwise after the script evaluation ends and stack is empty the result is a fail.[1] https://github.com/bitcoin/bitcoin/blob/a74bdeea1b8e27b2335f0f7da78006e87ecfb235/src/script/interpreter.cpp#L1983-L1986
[2] https://github.com/bitcoin/bitcoin/blob/a74bdeea1b8e27b2335f0f7da78006e87ecfb235/src/script/interpreter.cpp#L1823-L1824
In order to spend any of those scripts that end with OP_EQUALVERIFY the user would have to add an extra arbitrary value (that evaluates to true) to their signature script when spending the output.
Meaning for example if the number is x their spending script must be OP_1
Using OP_EQUAL fixes that.
How does it compare to what people have wrote, is the ChatGPT more optimized ?
It is more or less the same; for example, it's the same with this one. Interesting, ChatGPT can really help in programming but the user needs to understand the code to verify if there are no mistakes like you have pointed.
This mistakes usually come from outdated data ChatGPT is basing it's research.
Thanks for checking it, have a great day!
How does it compare to what people have wrote, is the ChatGPT more optimized ?
It is more or less the same; for example, it's the same with this one. Code:
OP_DUP OP_ADD OP_8 OP_ADD OP_SHA256OP_EQUALVERIFY
How does it compare to what people have wrote, is the ChatGPT more optimized ?
Code:
OP_DUP OP_DUP OP_ADD OP_8 OP_ADD OP_SHA256OP_EQUALVERIFY
Code:
OP_2DUP OP_ADD OP_8 OP_ADD OP_SHA256OP_EQUALVERIFY
Code:
OP_DUP OP_ADD OP_8 OP_ADD OP_SHA256OP_EQUALVERIFY
Code:
OP_DUP OP_DUP OP_ADD OP_8 OP_ADD OP_SHA256OP_EQUALVERIFY
Is this correct ?
Then I asked for optimized version:
Code:
OP_2DUP OP_ADD OP_8 OP_ADD OP_SHA256OP_EQUALVERIFY
This is the most optimized version according to ChatGPT:
Code:
OP_DUP OP_ADD OP_8 OP_ADD OP_SHA256OP_EQUALVERIFY
What you guys say ?
It's correct, except from the OP_MUL part, as that'd abort the script, because it is disabled. You might get the correct answer if you ask it to replace OP_MUL with one or more opcodes that are enabled and do the same operation. Code:
OP_DUP OP_2 OP_MUL OP_8 OP_ADD OP_SHA256OP_EQUALVERIFY
Not looking for merit.
I don't know anything about Bitcoin scripting, but this is what I've got from ChatGPT when asked for most optimized version
What you guys say ?
~
Alright thanks for this i will go through it and play around with some related stuffs Then I want to ask a question on how you generated the SHA 256 hash for 21,000,000... was there any encoding or let me just ask how??
Right, important. So, let me explain what's going on when I say that you hash the number 21 million. A hash function, as we all know, is a function that maps data of arbitrary size to a fixed-size output. The data that it takes as input usually comes in chunks of bytes. In this Github page, you can hash any value you want, with any encoding you want. In Bitcoin, OP_SHA256 takes as input bytes, with little endian order. This means that hashing the number 21 million in Bitcoin would look like this:
- Convert the number 21 million into hexadecimal, so that it's easier to manipulate. (You can use rapidtables.com)
- 21000000 = 0x1406F40
- Convert it to little endian: 0x406F4001 (Used this tool)
Now you need to pass these bytes (0x406F4001) into SHA256 using the Github page I posted above. It'll give you 0xdf3984c3d89ec61f93f2d3060263bbb960a885ffa5d41ca1eb9c2692de71d8b7.
It should be through trial and error because SHA256 can't be decoded
Since it's a one way encryption.
Important corrections:Since it's a one way encryption.
- This is not analogous to trial and error. When your input fails to produce the given hash, it does not give you any insights for your future selections, as with any cases where trial and error takes place (i.e., chess). What you probably meant is through brute force.
- Hashes, while used in encryption, are not encrypting anything, per se. It's a one way function. It simply digests a message.
- Encoding exists only in the input. For example, if you're hashing binary, will it be hex, or Base64? If you're hashing Text, will it be UTF-8?
Correct. However, with x=10499996, you're left with two items in the stack. That doesn't make the script incorrect, but it's better for your understanding to always be left with only one non-zero item.
Then I want to ask a question on how you generated the SHA 256 hash for 21,000,000... was there any encoding or let me just ask how??because I tried to read up on that and couldn't get a perfect answer for it, the generator I tried doesn't give me something reasonable to that .
Thus when I did wanted to test another number I used OP_SHA256 on the stack element I wanted to use just to get the hash value for testing... just curious how to get that hash format:
Code:
0xdf3984c3d89ec61f93f2d3060263bbb960a885ffa5d41ca1eb9c2692de71d8b7
Nice one Ambatman and promise444c5 I bet you guys learnt a lot too.
Since it's a one way encryption.
Alright Blackhatcoiner is soo close to 8000 merits
Why don't we take him there
Ambatman promise444c5 ??
Why don't we take him there
Ambatman promise444c5 ??
Correct. However, with x=10499996, you're left with two items in the stack. That doesn't make the script incorrect, but it's better for your understanding to always be left with only one non-zero item.
Then I want to ask a question on how you generated the SHA 256 hash for 21,000,000... was there any encoding or let me just ask how??because I tried to read up on that and couldn't get a perfect answer for it, the generator I tried doesn't give me something reasonable to that .
Thus when I did wanted to test another number I used OP_SHA256 on the stack element I wanted to use just to get the hash value for testing... just curious how to get that hash format:
Code:
0xdf3984c3d89ec61f93f2d3060263bbb960a885ffa5d41ca1eb9c2692de71d8b7
Nice one Ambatman and promise444c5 I bet you guys learnt a lot too.
[...]
Correct. However, with x=10499996, you're left with two items in the stack. That doesn't make the script incorrect, but it's better for your understanding to always be left with only one non-zero item. Code:
`OP_DUP OP_ADD OP_8 OP_ADD OP_SHA256 OP_PUSHDATAOP_EQUAL`
When I did I added only the value of X to the stack data and the script ran just fine however I didn't drop it here because I got a final output of 0.
Thanks for the quiz man I learnt a lot. Let's just say with this quiz I've been able to understand how to create simple bitcoin scripts. +1 Blackhatcoiner I look forward to the next quiz
Nice one Ambatman and promise444c5 I bet you guys learnt a lot too. See you all around. See yah Blackhatcoiner on the technical board
Is there any site or app that can help in testing my knowledge?
Like small challenges in Script? I don't think there is. You can try and do something else, which we might do it the next quiz. Try making a custom script, like the one you made in this thread, and compile its address. For example, for your script, the P2WSH testnet address is: tb1qs462fyl73n460uztz4qjh573vcuh9wfay4upmmz98pveevxrvydq3t53pw. There's a "Compile your script" option in Script Wiz. Any amount of tBTC sent to that address can only be spent if the spender provides <10499996> as the only stack element in their witness. A good exercise would be to spend money from that address, or at least provide the raw transaction which could be confirmed. (You can't broadcast it, because it is non-standard. Some miner would have to pick it for you, and include it in a block.)
[...]
Correct. However, with x=10499996, you're left with two items in the stack. That doesn't make the script incorrect, but it's better for your understanding to always be left with only one non-zero item. Code:
`OP_DUP OP_ADD OP_8 OP_ADD OP_SHA256 OP_PUSHDATAOP_EQUAL`
Code:
OP_DUP OP_ADD OP_8 OP_ADD OP_SHA256OP_EQUAL
Is there any site or app that can help in testing my knowledge?
Tried searching via web but most are just single questions on Githubs.
It's showing stack data must include min 2 data and I don't know what to place there at part from <10499996>
NGL scriptwiz requires a manual.
use the hash(SHA256) from the question itself,it should be fixed
[...]
Correct. However, with x=10499996, you're left with two items in the stack. That doesn't make the script incorrect, but it's better for your understanding to always be left with only one non-zero item. Code:
`OP_DUP OP_ADD OP_8 OP_ADD OP_SHA256 OP_PUSHDATAOP_EQUAL`
Code:
OP_DUP OP_ADD OP_8 OP_ADD OP_SHA256OP_EQUAL
It's showing stack data must include min 2 data and I don't know what to place there at part from <10499996>
NGL scriptwiz requires a manual.
use the hash(SHA256) from the question itself,it should be fixed
Code:
OP_SWAP OP_DUP OP_8 OP_ADD OP_SHA256 OP_EQUAL
Code:
OP_DUP OP_ADD OP_8 OP_ADD OP_SHA256OP_EQUAL
Now I understand especially while using it with scriptwiz
OP DUP duplicates doesn't mean it automatically adds the duplicates
OP _ ADD helps with that which I did
And found out that OP_SWAP felt out of place.
Used the above code and the values I got were getting similar to yours until I used OP_EQUAL and I was given this
It's showing stack data must include min 2 data and I don't know what to place there at part from <10499996>
NGL scriptwiz requires a manual.
Edit
Added <10499996> to the stack making it two
And the error message seized and replaced by zero
Code:
OP_2 OP_MUL OP_8 OP_ADD OP_SHA256 OP_DATA_32OP_EQUAL
Code:
`OP_DUP OP_ADD OP_8 OP_ADD OP_SHA256 OP_PUSHDATAOP_EQUAL`
I replaced the OP_2 OP_MUL which if run on the script does the job of multiplying the target value 'x' by 2 to give the equivalent of '2x ' in the data stack.
To modify the script I used OP_DUP which would duplicate the target value 'x' then I also added 'OP_ADD ' to add the target value 'x' so instead of getting 2*x to give 2x like in the old code, we now get ( x +x ) which is still equivalent to 2x.
I also replaced
Code:
'OP_DATA_32OP_EQUAL'
Code:
'OP_PUSHDATAOP_EQUAL`
I hope I'm right this time
edited out
How about this :Code:
OP_2
OP_SWAP
OP_DUP
OP_ADD
OP_8
OP_ADD
OP_SHA256
<0xdf3984c3d89ec61f93f2d3060263bbb960a885ffa5d41ca1eb9c2692de71d8b7>
OP_EQUAL
For anyone who wants the solution, it's x=10499996. For that value, 2x + 8 = 21000000, and SHA256(21000000) = 0xdf3984c3d89ec61f93f2d3060263bbb960a885ffa5d41ca1eb9c2692de71d8b7.
Really close. It'd be correct if OP_MUL was enabled, but it's disabled. You need to replace it with another opcode (or more than one). (And of course, you need to remove OP_DATA_32 as it does not exist.)
This one is incorrect. I think that you've misunderstood what OP_DUP does, because you're just one placement away from the solution. Put your code into Script Wiz, using <10499996> as the only stack element, and see what you get:
Hint: You need to add just one more opcode, somewhere.
Code:
OP_2 OP_MUL OP_8 OP_ADD OP_SHA256 OP_DATA_32OP_EQUAL
Code:
OP_SWAP OP_DUP OP_8 OP_ADD OP_SHA256 OP_EQUAL
Code:
<0xdf3984c3d89ec61f93f2d3060263bbb960a885ffa5d41ca1eb9c2692de71d8b7>
OP_SWAP
OP_DUP
OP_8
OP_ADD
OP_SHA256
OP_EQUAL
Hint: You need to add just one more opcode, somewhere.
i actually dont know how to solve your question but I just want to say I put your question in ChatGPT and the bot answered all the detail? I don't know if the answer is correct answer or not but don't you think there will be a member that use AI for the answer.
You can paste the answer. I have crafted these questions in such a way that ChatGPT would most likely fail in all of them.[...]
You're close as well. Just read what I've said to the others.
I went through it and i tried giving it a shot, it was challenging for me because i have no experience about it but firstly i had to go through https://en.bitcoin.it/wiki/Script then i went through https://bitcoindev.network/bitcoin-script-101/ and read a little from https://learnmeabitcoin.com/technical/cryptography/hash-function/
from the https://ide.scriptwiz.app/ i tried testing and got 0, then i need to test for true which is "1" so i used the target hash of <0x4307fbbb7e5b7c8f0339b060d171c49c881901d78ab712e60d805af9f9dc4ca1> and i got 1 (using 496 on stack element ) . i don't know if i'm right though
from the https://ide.scriptwiz.app/ i tried testing and got 0, then i need to test for true which is "1" so i used the target hash of <0x4307fbbb7e5b7c8f0339b060d171c49c881901d78ab712e60d805af9f9dc4ca1> and i got 1 (using 496 on stack element ) . i don't know if i'm right though
Code:
OP_DUP
OP_2
OP_MUL
OP_8
OP_ADD
OP_SHA256
<0xdf3984c3d89ec61f93f2d3060263bbb960a885ffa5d41ca1eb9c2692de71d8b7>
OP_EQUAL
hI BlackHatCoiner
i actually dont know how to solve your question but I just want to say I put your question in ChatGPT and the bot answered all the detail? I don't know if the answer is correct answer or not but don't you think there will be a member that use AI for the answer.
You know that AI getting crazy nowadays
Wow AI has gotten this Far i actually dont know how to solve your question but I just want to say I put your question in ChatGPT and the bot answered all the detail? I don't know if the answer is correct answer or not but don't you think there will be a member that use AI for the answer.
You know that AI getting crazy nowadays
I guess I underestimated their capabilities since ain't quite fond of having a dependence on something that isn't quite mine.
The essence of this questions if I ain't mistaken is to help beginners or individuals interested improve their knowledge.
If a person do rely on ChatGPT, there's no way they can truly grow.
For instance if it wasn't for Mia Chloe mistakes and corrections from BlackHatCoiner I wouldn't know anything close to the preliminary I have learnt.
hI BlackHatCoiner
i actually dont know how to solve your question but I just want to say I put your question in ChatGPT and the bot answered all the detail? I don't know if the answer is correct answer or not but don't you think there will be a member that use AI for the answer.
You know that AI getting crazy nowadays
i actually dont know how to solve your question but I just want to say I put your question in ChatGPT and the bot answered all the detail? I don't know if the answer is correct answer or not but don't you think there will be a member that use AI for the answer.
You know that AI getting crazy nowadays
I think am getting there. This is the first am quite understanding Bitcoin scripts.
Let's see
Not quite conversant with much but I did draw some inspiration from Mia Chloe work and tried mine.
Though couldn't use the site that was recommended to check but
This is how I ended with this.
I removed OP _DATA_32 because like you said I couldn't find it.
Removed OP_MUL because it has been disabled
Removed OP _2 because there's no need for pushing two since we already used OP _ DUP to duplicate x ( the top stack)
and used OP _EQUAL because it's the only one I saw that supports an output been either True or false without a SIG.
Where OP _EQUALVERIFY would make the transaction as invalid if it's not true
The question one that requires the result to be true which doesn't quite require OP _ VERIFY.
This is the little I can gather..... Would improve more since I just learnt a preamble from this thread.
Let's see
Code:
OP_SWAP OP_DUP OP_8 OP_ADD OP_SHA256 OP_EQUAL
Not quite conversant with much but I did draw some inspiration from Mia Chloe work and tried mine.
Though couldn't use the site that was recommended to check but
This is how I ended with this.
I removed OP _DATA_32 because like you said I couldn't find it.
Removed OP_MUL because it has been disabled
Removed OP _2 because there's no need for pushing two since we already used OP _ DUP to duplicate x ( the top stack)
and used OP _EQUAL because it's the only one I saw that supports an output been either True or false without a SIG.
Where OP _EQUALVERIFY would make the transaction as invalid if it's not true
The question one that requires the result to be true which doesn't quite require OP _ VERIFY.
This is the little I can gather..... Would improve more since I just learnt a preamble from this thread.
Code:
`OP_DATA_32OP_SWAP OP_DUP OP_2 OP_MUL OP_8 OP_ADD OP_SHA256 OP_EQUAL`
I removed the `OP_CHECKSIG` command since I think its not necessary for the script like you said. I also replaced `OP_EQUALVERIFY` with `OP_EQUAL`, this should prevent the script from failing if the equation is not solved but rather it should simply return false instead.
Code:
OP_2 OP_MUL OP_8 OP_ADD OP_SHA256 OP_DATA_32OP_EQUAL
I'm not sure though but `OP_DUP` may not be needed too since the input `x` is already on the stack.
Code:
OP_DUP OP_2 OP_MUL OP_8 OP_ADD OP_SHA256 OP_DATA_32OP_EQUAL
In this other one I tried removing the `OP_SWAP` command
Let's test this, opcode by opcode. (You can verify your scripts yourself, btw, by using https://ide.scriptwiz.app/)
This one will abort. By the way, why did you put an OP_CHECKSIG? There is no signature, nor public key to check. It's just an equation. If you solve it, you get the coins. That's it.
OP_EQUALVERIFY will fail the script. You're that close! Copy and paste your code into the Script Wiz (with OP_CHECKSIG deducted), and find your mistake:
(In stack elements, just use a random number, like <1000>)
| Opcode | Stack |
| <0xdf39...d8b7> 1000 | |
| OP_DUP | <0xdf39...d8b7> 1000 1000 |
| OP_2DUP | <0xdf39...d8b7> 1000 1000 1000 1000 |
| OP_ADD | <0xdf39...d8b7> 1000 1000 2000 |
| OP_8 | <0xdf39...d8b7> 1000 1000 2000 8 |
| OP_ADD | <0xdf39...d8b7> 1000 1000 2008 |
| OP_SHA256 | <0xdf39...d8b7> 1000 1000 <0xc91d...dc80> |
| OP_SWAP | <0xdf39...d8b7> 1000 <0xc91d...dc80> 1000 |
| OP_EQUALVERIFY | <0xdf39...d8b7> 1000 <0xc91d...dc80> 1000, Stack failed an OP_VERIFY operation. Top two items are not equal. |
| OP_CHECKSIG |
This one will abort. By the way, why did you put an OP_CHECKSIG? There is no signature, nor public key to check. It's just an equation. If you solve it, you get the coins. That's it.
- `OP_DATA_32 ` from my understanding so far this pushes the target_hash onto the stack (32 bytes)
I'm not aware of an OP_DATA_32 op code. If you want to put Alice's hash in the stack, just enter it with no opcodes, like this: OP_EQUALVERIFY will fail the script. You're that close! Copy and paste your code into the Script Wiz (with OP_CHECKSIG deducted), and find your mistake:
Code:
<0xdf3984c3d89ec61f93f2d3060263bbb960a885ffa5d41ca1eb9c2692de71d8b7>
OP_SWAP
OP_DUP
OP_2
OP_MUL
OP_8
OP_ADD
OP_SHA256
OP_EQUALVERIFY
(In stack elements, just use a random number, like <1000>)
Code:
OP_DUP
OP_2DUP
OP_ADD
OP_8
OP_ADD
OP_SHA256
OP_SWAP
OP_EQUALVERIFY
OP_CHECKSIG
`
Code:
`OP_DATA_32OP_SWAP OP_DUP OP_2 OP_MUL OP_8 OP_ADD OP_SHA256 OP_EQUALVERIFY OP_CHECKSIG`
After my long reading and multiple tries, I was able to come up with the two scripts above.
The script actually takes two inputs which are
`x` (this is the solution to the equation)
`target_hash` (which is the expected hash value)
- `OP_DATA_32
- `OP_SWAP` while this swaps the top two stack items (x and target_hash)
- `OP_DUP` this part is supposed to duplicate the top stack item which is 'x'
- `OP_2` this one is supposed to push the number 2 onto the stack
- `OP_MUL` this multiplies x by 2
- `OP_8` this one pushes the number 8 onto the stack
- `OP_ADD` adds 8 to the result ( 2x + 8 )
- `OP_SHA256` from my understanding so far this one calculates the SHA256 hash of the result
- `OP_EQUALVERIFY` I think this should check if the hash equals to the target hash and If not the script should fail
- `OP_CHECKSIG` this actually checks the signature
Alright Blackhatcoiner I think this is the best I can come up with from what I've read so far.
Friends, a script. A Bitcoin script. 
Like this one:
This one is taken from bitcoin.it/Script, and it is the standard script used when sending bitcoin. When locking bitcoin to that script, the unlocking script requires the spender to provide a valid signature and public key in the stack of elements.
This is a step-by-step description of what happens in each opcode:
Like this one:
Code:
OP_DUP OP_HASH160OP_EQUALVERIFY OP_CHECKSIG
This one is taken from bitcoin.it/Script, and it is the standard script used when sending bitcoin. When locking bitcoin to that script, the unlocking script requires the spender to provide a valid signature and public key in the stack of elements.
This is a step-by-step description of what happens in each opcode:
| Opcode | Stack |
| OP_DUP | |
| OP_HASH160 | |
| Adding | |
| OP_EQUALVERIFY | |
| OP_CHECKSIG | 1 (returns 1 if the signature is valid, otherwise 0) |
tried with JS
never wrote a script before so it might be wrong
used node, installed the package along
never wrote a script before so it might be wrong
used node, installed the package along
Code:
const bitcoin = require('bitcoinjs-lib');
// Defines the hash value Alice wants to match
const targetHash = Buffer.from('df3984c3d89ec61f93f2d3060263bbb960a885ffa5d41ca1eb9c2692de71d8b7', 'hex');
// Creates the locking script
const script = bitcoin.script.compile([
bitcoin.opcodes.OP_DUP,
bitcoin.opcodes.OP_2,
bitcoin.opcodes.OP_MUL,
bitcoin.opcodes.OP_8,
bitcoin.opcodes.OP_ADD,
bitcoin.opcodes.OP_SHA256,
targetHash,
bitcoin.opcodes.OP_EQUAL
]);
// Creates a P2SH address from the script
const { address } = bitcoin.payments.p2sh({
redeem: { output: script, network: bitcoin.networks.testnet },
network: bitcoin.networks.testnet
});
console.log('P2SH Address:', address);
// Create a new transaction
const psbt = new bitcoin.Psbt({ network: bitcoin.networks.testnet });
// Add input (replace with actual transaction details)
//must be 32 bit
psbt.addInput({
hash: 'your-transaction-hash', // Replace with actual transaction hash
index: 0, // Replace with actual index
nonWitnessUtxo: Buffer.from('your-raw-transaction-hex', 'hex') // Replace with actual raw transaction hex
});
// Add output to the P2SH address
psbt.addOutput({
address: address,
value: 1000 // Value in satoshis
});
// Sign the transaction (replace with actual keyPair)
const keyPair = bitcoin.ECPair.makeRandom({ network: bitcoin.networks.testnet });
psbt.signInput(0, keyPair);
// Finalize and build the transaction
psbt.finalizeAllInputs();
const tx = psbt.extractTransaction();
console.log('Transaction Hex:', tx.toHex());
[...]
Remember that the script we're talking about is a Bitcoin script, not a python script. You need to construct a script based on Script.Also, please note that I'm not asking you to solve the equation, which is what you're doing in your python script. I'm asking you to construct a script that would check if the equation is solved. For example, check out these scripts. There, the equation is hash(x) = hash(y) for x != y, or in English, "find two different inputs which produce the same hash". You obviously can't find which these inputs are (hereby the bounty), but you can construct scripts that can validate this condition.
[...]
Remember that the script we're talking about is a Bitcoin script, not a python script. You need to construct a script based on Script.Also, please note that I'm not asking you to solve the equation, which is what you're doing in your python script. I'm asking you to construct a script that would check if the equation is solved. For example, check out these scripts. There, the equation is hash(x) = hash(y) for x != y, or in English, "find two different inputs which produce the same hash". You obviously can't find which these inputs are (hereby the bounty), but you can construct scripts that can validate this condition.
Nice one Blackhatcoiner.
Well I have an idea of what to do however my phyton scripting skills are quite low anyways I was able to write these two scripts I don't know if they'll do. I tried running them on my mobile phone with a phyton compiler but it seems I'll need more computational power to run the test however Im not with my PC now. Hopefully the script is correct.
Well I have an idea of what to do however my phyton scripting skills are quite low anyways I was able to write these two scripts I don't know if they'll do. I tried running them on my mobile phone with a phyton compiler but it seems I'll need more computational power to run the test however Im not with my PC now. Hopefully the script is correct.
Code:
import hashlib
def find_x():
target_hash = "df3984c3d89ec61f93f2d3060263bbb960a885ffa5d41ca1eb9c2692de71d8b7"
for x in range(2**32):
result = 2*x + 8
hash_result = hashlib.sha256(str(result).encode()).hexdigest()
if hash_result == target_hash:
print(f"x = {x}")
break
find_x()
Code:
import hashlib
def find_x():
target_hash = "0xdf3984c3d89ec61f93f2d3060263bbb960a885ffa5d41ca1eb9c2692de71d8b7"
for x in range(2**32):
if x % 100000 == 0: # Print progress
print(f"Trying x = {x}")
result = 2*x + 8
hash_result = hashlib.sha256(str(result).encode()).hexdigest()
if hash_result == target_hash:
print(f"x = {x}")
break
find_x()
Missed me? Time for another quiz.
- What's this?
Bitcoin quizzes are technical questions of educational character that improve the average user's knowledge on Bitcoin, and help him rank up. You can read more about it in here.
Answer the question correctly and earn merits.
Alice wants to construct a Bitcoin script, which can be validated only if the spender provides a solution to the equation: SHA256(2x + 8) = 0xdf3984c3d89ec61f93f2d3060263bbb960a885ffa5d41ca1eb9c2692de71d8b7.
In other words, Alice wants to send a bitcoin to an address, which is a script. In order for Bob to claim the bitcoin, he needs to find a 32-bit value for x, such that once you double it, add 8 to it, and pass that result into SHA256, the hash would be equal with Alice's hash.
Can you construct this script? You might find the following links useful:
Jump to: