Everyone else is doing "beginner" tutorials. You're the only person I've found who does legit, intermediate-advanced tutorials. Your channel is an excellent resource. Thank you for the work you've done!
@@smartcontractprogrammer , thanks for a great tutorial. I'm tryna access the values of mapping(address => unit) via ethers.js, but nothing doesn't work. I managed to get values for all privimitive types, but stuck at calculating the hash for getStorageAt(). Could you please help me out?
@@viktorlavrenenko1713 You dont have to use soliditySha3 to hash an address as the address is already an hash itself. You have to pad the address to 32bytes (64 chars) and the same must be done with slot (in hex format). Then keccack256 the concatenation of the padded address and padded slot. hash = Utils.leftPad(Utils.stripHexPrefix(key), 64); hash += Utils.padLeft(Utils.stripHexPrefix(Utils.toHex(slot)), 64); hash = Utils.keccak256("0x" + hash);
Wow, great video, I got some eth stuck in the contract I deployed without a transfer function in it, how to destroy that contract and send the eth to another address?
I have no words for the author and many thanks for his efforts, I would like to ask a question here .. you had said that data of dynamic array element data will be stored at keccak256() , that mean keccak256(6) ll always be same, So what happens if two contract which had dynamic array at slot number 6 .. Contract 1 - Dynamic array at Slot 6 will also point at the same place where Contract 2 - Dynamic array at Slot 6 will point Does that mean the values ll be overwritten ,, Offcoure that should not be possible .. So can anyone help me understand that what I am missing here?
Yes! But keep in mind that data stored on the blockchain is permanent. So if the hash function becomes decipherable in the future, then the password can be recovered from the password hash stored on the blockchain.
Hi. I don't know if you can see my comment now after all it was one year old tutorial. First, I 'd like to say thank you, I learned a lot from you. I'd like to confirm a point that you say the size of EVM storage is 2**256 slots times 32 bytes. I doubt the number. You know the 2**256 * 32 bytes is a very big number. 1TB disk can only store 2**40 Byte. Can you double check this or if what I understood is not correct, please let me know. Thanks
all data including private can be read some data can be written, depends on what your smart contract allows private data can be written only if you have a function that allow other accounts / contracts to call
Vulnerability 0:40
Storage layout 1:41
Code 4:57
Setup 10:09
Demo 10:38
Preventative technique 16:54
Everyone else is doing "beginner" tutorials. You're the only person I've found who does legit, intermediate-advanced tutorials. Your channel is an excellent resource. Thank you for the work you've done!
That is exactly why I created this channel!
@@smartcontractprogrammer , thanks for a great tutorial. I'm tryna access the values of mapping(address => unit) via ethers.js, but nothing doesn't work. I managed to get values for all privimitive types, but stuck at calculating the hash for getStorageAt(). Could you please help me out?
@@smartcontractprogrammer you should be paid for just been alive.
Fixed it
@@viktorlavrenenko1713 You dont have to use soliditySha3 to hash an address as the address is already an hash itself. You have to pad the address to 32bytes (64 chars) and the same must be done with slot (in hex format). Then keccack256 the concatenation of the padded address and padded slot.
hash = Utils.leftPad(Utils.stripHexPrefix(key), 64);
hash += Utils.padLeft(Utils.stripHexPrefix(Utils.toHex(slot)), 64);
hash = Utils.keccak256("0x" + hash);
the most simplest explanation of one of the advanced concepts. Awesome.
wow! this video was more informative than other 52 channels I watched and spent 40 hours
Thanks so much! You show me the new world with such an excellent course!
Bro, you are just awesome, no words. Great content 👌
Thanks :)
I want to thank you for your work sir, knowledge is a treasure to share. Again thank you
From South Africa❤, I love your videos you explain concept very easily big ups
Thanks
You are a gem. excellent explanation. Love you brother.
Wow, awesome video! Very insightful and well explained
Brilliantly clear demonstration !!!
This is great info . Thank you for the advanced solidity content.
BEST CHANNEL ON TH-cam U NEED A MILLION VIEWZZ
i love the level of this content, thank you!
Amazing, Amazing, Amazing!
By the way congrats bro, we got 500 subscribers 😎😎 it's just starting only.
💯💯💯💯💯
Great video, congrats
That's pretty crazy that password could be hacked on blockchain !!! 😮 thanks so much for the video !! 😍
Yeah, don't store passwords on the blockchain
@@smartcontractprogrammer Yes sir !!
any advanced solidity i search ur channel pops up 😂😂
Great video, I appreciate your work!
amazing!
content 💥.
you're brilliant! what a great channel
I can feel my brain growing
Thanks a lot for your videos. Your explanations are incredible good! ¡Muchas gracias!
Great videos keep making them!
Nice VID! How would u decode the address ?
Wow, great video,
I got some eth stuck in the contract I deployed without a transfer function in it, how to destroy that contract and send the eth to another address?
what a great channel
Really informative sir
great work!
Thanks!!! Great tutorial!
is this working on 0.8 or further versions??
I have no words for the author and many thanks for his efforts,
I would like to ask a question here .. you had said that data of dynamic array element data will be stored at keccak256() , that mean keccak256(6) ll always be same, So what happens if two contract which had dynamic array at slot number 6 ..
Contract 1 - Dynamic array at Slot 6 will also point at the same place where
Contract 2 - Dynamic array at Slot 6 will point
Does that mean the values ll be overwritten ,, Offcoure that should not be possible .. So can anyone help me understand that what I am missing here?
Each contract have separate storage
So we can store sensitive information by storing their hash in the blockchain right?
Yes! But keep in mind that data stored on the blockchain is permanent. So if the hash function becomes decipherable in the future, then the password can be recovered from the password hash stored on the blockchain.
OK, never keep sensitive info in blockchain, got it👍
You can use Filecoin/IPFS to store data outside of blockchain.
Haha this preventive technique. Thx for this vdo
can we get read contract storage that deployed on testnets ? ( like on remix ) or browser console ?
yes
Hi. I don't know if you can see my comment now after all it was one year old tutorial. First, I 'd like to say thank you, I learned a lot from you. I'd like to confirm a point that you say the size of EVM storage is 2**256 slots times 32 bytes. I doubt the number. You know the 2**256 * 32 bytes is a very big number. 1TB disk can only store 2**40 Byte. Can you double check this or if what I understood is not correct, please let me know. Thanks
2**256 possible slots
not all slots are used
@@smartcontractprogrammer thank you!
So there is no way to create passwords on solidity, that sucks
does this apply to incrementing variables as well?
accessing private state variables that are used to increment stuff?
@@smartcontractprogrammer yes with public function and modifier that only allowes certain contracts address. How secured is this approach?
all data including private can be read
some data can be written, depends on what your smart contract allows
private data can be written only if you have a function that allow other accounts / contracts to call
It looks like a mistake in video, in code comments you put "(2 ** 8) * 32" for uint slot. But uint uses only 256 bit and not 256 * 32?