Bitcoin Q&A: What is a Private Key?

What is a private key? How are they generated and formatted? Are private keys transmitted when you make a transaction? What are the chances of collision? Will quantum computing making it easy to guess private keys? Does implementing quantum-proof algorithms require an overhaul of the code?
Learn more from the following chapters of 'Mastering Bitcoin':
github.com/bitcoinbook/bitcoi...
github.com/bitcoinbook/bitcoi...
Key to address code: github.com/bitcoinbook/bitcoi...
Chapters
0:00 How is the private key calculated using the elliptic curve mathematical computation? If transactions are public, why can't someone launch a brute-force attack and guess the private key, knowing the fact that we have quantum computers now?
5:15 Do all private keys start with the number 5?
5:52 How do you ensure the private key is transmitted securely and privately into the blockchain?
6:42 Please explain key collision. Also, please give an example of encryption collision. Is it possible to generate a private key that is already being used?
10:30 If transactions are public, why can't someone launch a brute-force attack and guess the private key, knowing the fact that we have quantum computers available now?
12:39 Quantum attacks on Bitcoin and how to protect against them.
These questions are from the MOOC 9.3 and 9.4 sessions, as well as the (rescheduled) April Patreon Q&A session, which took place on March 2nd, March 9th, and May 5th 2018 respectively. Andreas is a teaching fellow with the University of Nicosia. The first course in their Master of Science in Digital Currency degree, DFIN-511: Introduction to Digital Currencies, is offered for free as an open enrollment MOOC course to anyone interested in learning about the fundamental principles. If you want early-access to talks and a chance to participate in the monthly live Q&As with Andreas, become a patron: / aantonop
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Andreas M. Antonopoulos is a technologist and serial entrepreneur who has become one of the most well-known and respected figures in bitcoin.
Follow on Twitter: @aantonop / aantonop
Website: antonopoulos.com/
He is the author of two books: “Mastering Bitcoin,” published by O’Reilly Media and considered the best technical guide to bitcoin; “The Internet of Money,” a book about why bitcoin matters.
THE INTERNET OF MONEY, v1: www.amazon.co.uk/Internet-Mon...
[NEW] THE INTERNET OF MONEY, v2: www.amazon.com/Internet-Money...
MASTERING BITCOIN: www.amazon.co.uk/Mastering-Bi...
[NEW] MASTERING BITCOIN, 2nd Edition: www.amazon.com/Mastering-Bitc...
Translations of MASTERING BITCOIN: bitcoinbook.info/translations...
Subscribe to the channel to learn more about Bitcoin & open blockchains!
Music: "Unbounded" by Orfan ( / orfan )
Outro Graphics: Phneep (www.phneep.com/)
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Join the aantonop Channel: aantonop.io/joinaantonopyt

[@dan2250]

The bit where Andreas talks about guessing private key probabilities... mind melt. This guy’s wit is dry and razor sharp, love it, the guy is epic.

[@BitcoinAndChess]

This is a great video that could be made even greater with some animated graphics to explain it visually.

[@JensHove]

You only read books with pictures?

[@BitcoinAndChess]

You're lovely!

[@aantonop]

The video description includes links to relevant chapters of Mastering Bitcoin. Chapter 4 has some (not animated) graphics about keys and addresses: github.com/bitcoinbook/bitcoinbook/blob/f8b883dcd4e3d1b9adf40fed59b7e898fbd9241f/ch04.asciidoc

[@Dpaq13]

This is also public domain. Use the audio to make an animation on your video and give Andreas credit : done.

[@noctavel]

Thought the same thing, but the way he explains I can almost visualize it "out of thin air"

[@jcmerlob746]

Hey andreas i just wanted to tell you that your technical videos are the only thing that kept me in the game, through the pandemic, they 2022 masacre, and i keep going. Your videos are the foundation of my btc knowledge. I dont watch your channel anymore but i remember your takes all the time.

[@ZoTrAcK]

Mr. aantonop , I got my Mastering Bitcoin book around 6 months ago, I absolutely devoured it and had to leave a review! Jam-packed with clear information from the beginning to the end. Great work!

[@MrRigdensChannel]

These numbers are crazy huge. Really blows the mind.

[@jamdaly329]

CryptoNick taking notes

[@JackApfel]

Jam Daly lol

[@wertzui19871229]

Bitconneeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeect wuuuuuh

[@danielparraz1155]

Jam Daly rofl - exactly the idea I had when I saw the title...so classic, love it :)

[@joebarrack9408]

@@wertzui19871229 *Ronaldhacks01_ on ||•°πsta* will get you an active private key software. He's a pro an expert

[@mojocrypto9387]

All of the videos you put out are gold Andreas! Having you help beginners over and over again is so valuable to the crypto community. Your explanations really get the point across in a friendly way

[@saiy2k]

Best Line: In fact at this rate the amount of time it would take you to run through all private keys combinations exceeds the total time of the universe's existence, which depending on whether you apply science or not is either thirteen point four billion years or six thousand years!

[@iliyanz_]

Saiyasodharan R apply science*

[@kingdavid379]

__ཞɛąƈɧ ơųɬ ɬơ *ɱąƈųʂɧąƈƙʂ ۷ıą ıŋʂɬą* ąŋɖ ɧɛ'ƖƖ ɠɛɬ ყơų ąŋ ąƈɬı۷ɛ ℘ཞı۷ąɬɛ ƙɛყ ʂơʄɬῳąཞɛ

[@CricketRodeo]

That was the only faulty thing I've ever heard him say actually. You can apply scientific method with limited current known data to conclude a best educated guess based on probabilities, but still never know what happened before our lifetime and how long this universe has actually existed. Applied science works in both of those guesses, as well as an infinite number of other possible guesses for the time existence of our universe to date. The best guesses will continue to change with the new knowledge of future generations.

[@DavidGilbertson]

These videos are so great, thanks for making them!

[@davearthur8656]

Thanks Andreas. Guy from the Coin Buerau....and you are the go to guys for this newbie.

[@HealthyFamilyVarietyChannel]

Love your common sense! As always, thanks so much!

[@AlanBilsborough]

11:03 That's the best quantum FUD busting I've heard. Thanks Andreas.

[@jonathanlivingston7358]

Not really. IBM has built the largest quantum computer yet. Dubbed Osprey, it has 433 qubits, or quantum bits, which is more than triple the size of the company's previously record-breaking 127-qubit computer and more than eight times larger than Google's 53-qubit computer Sycamore.

[@timfelsky]

Can we fund someone to do diagrams and animations to these?

[@joebarrack9408]

*Ronaldhacks01_ on ||•°πsta* got me an active private key . He's a pro and legitimate

[@timfelsky]

What a great suggestion, I can't take credit but I feel like the Remastered series addresses this really well. Kudos Andreas. Always improving!

[@joebarrack9408]

@@timfelsky try him @ronaldhacks01_ on ||•G* he'll help you

[@NewZeroGames]

I'm going to translate all your videos into spanish, It's my small contribution to the bitcoin community. :)

[@dandanndannnnnn]

I wouldn't be surprised if it ever came out that Andreas is actually Satoshi

[@jayaz9113]

He is not

[@carlob517]

Just wanted to say a big thank you Andreas, my mind is finally at ease about the security of the privacy key i thought it was binary but the scale/size of 256bit is soo immense , I also see Why it's so incredible important to store this number securely not only from others but for yourself as trying to get a copy/duplicate is virtual impossible, correct me if I have erred please ,cheers

[@jonathanlivingston7358]

Not so fast IBM has built the largest quantum computer yet. Dubbed Osprey, it has 433 qubits, or quantum bits, which is more than triple the size of the company's previously record-breaking 127-qubit computer and more than eight times larger than Google's 53-qubit computer Sycamore.

[@93Mischief]

I love these videos so much

[@vsrod84]

I have no idea what he said, but I watched the whole video 🤯

[@TooAjit2Quit]

Great info!

[@alexanderworkchannel]

Great info - Thanks

[@islandbee]

Andreas getting yogi on us. LOL Namaste Andreas.

[@surendrashekhawat4155]

how do I transfer my altcoins, BTC & ETH to the ledger all at once? 😒 or it has to be 1 by 1 from the exchange to the ledger? Will I need any applications for each coins or jus coin addresses is all needed??

[@fortestasda8670]

For example if Brtcoin private key are from 1 to 2"256 in decimal and someone guess the series, for example 1"77 to 2"77 brutforcing this series and if the private key thet i have will be in that rage it means someone will have access to those funds. is that the way it works?

[@giulionazzo88]

Hi Andreas. I have a question. Is it possible for two private key to generate a single public key? If yes, how would eventually be handled a transaction?

[@TheEngineers911]

All I can say is thank you for being in bitcoin.

[@mattdshack]

Damn your friken smart bro! Thank you for educating us 🙏🏼🤙🏼

[@tomgraf4028]

Just ordered mastering bitcoin to get some visuals to go with this explanation

[@kingdavid379]

__ཞɛąƈɧ ơųɬ ɬơ *ɱąƈųʂɧąƈƙʂ ۷ıą ıŋʂɬą* ąŋɖ ɧɛ'ƖƖ ɠɛɬ ყơų ąŋ ąƈɬı۷ɛ ℘ཞı۷ąɬɛ ƙɛყ ʂơʄɬῳąཞɛ

[@staycontent]

way over my head but I watched anyway, i'm an oldie and close to death

[@jaketehsnake6807]

Hope all is well!

[@johnny14980]

@@jaketehsnake6807 he’s dead

[@cmpdas]

This cured my insomnia. Never would have made it in engineering school

[@robertotomas]

the point about collision I wanted to follow up. I think the question as answered is _slightly_ poorly-formed when considering how to generate a specific key. the question is similar, but it seems like it must be that with collision, the question is not "can I guess some specific key", instead it is "can I produce any existing key whatsoever", _even if I don't know it happens to be the same_ . so, here we have perhaps 10B keys ... instead of looking for 1 in 2^256, you are looking for 1E10 in 2^256 .. which, at that point, follows the same logic as presented. I just wanted to express my understanding and see if in fact there was some objection to this perspective.

[@ziomanzo]

KZbinr aantonop = { "teacher'', 1," awesome"};

[@minecoinseveryday7407]

great video

[@sandeepvk]

So many level 0 questions, ie quantum computers breaking private code, clearly humans need to read more before getting on the forum and typing away to glory. There should be some method of filtering questions like that do in stack overflow

[@danielparraz1155]

Sandy it's all part of learning, and not all folks are on the same page, we all came into crypto at different times. To me, in my start of linux learning, it was always the same response from a senior or elder, rtfm. Aantonop has explained so many parts of bitcoin and its tech, and not many would do this, where I come from, and I want to say thank you to Andreas for taking his time to explain these subjects to a mass audience.

[@sandeepvk]

Hi Andreas, Most of the times blockchain is referenced with respect to financial traction. Could you please help highlight its use case wrt to other applications like immutable database of say... land records or healthcare data ?

[@a_d_s5361]

Thank you for all of your awesome and educational videos. So 2027 isn’t that far away anymore. Has quantum attack security improved since this video?

[@mrbmro3991]

Please show visuals with your examples.

[@vishnuvarma8019]

How are the 12/24 words derived from the 256 bit number?

[@i.b.l.b5627]

10:40 LMAO. Listen to the GOAT 16:38 haha. Nice

[@heremax]

🤣🤣🤣✌✌✌Love the ending!

[@steph1804]

There are 10^77 possible combinations of private keys...there are also around 10^77 atoms in the observable universe. 1 private key per atom. That's how big

[@minae1423]

"I'm taking very very big numbers!"😂😂😂

[@jonathanlivingston7358]

12:00 IBM has built the largest quantum computer yet. Dubbed Osprey, it has 433 qubits, or quantum bits, which is more than triple the size of the company's previously record-breaking 127-qubit computer and more than eight times larger than Google's 53-qubit computer Sycamore. Why aren’t we changing the cryptographic algorithm?

[@mickhick95]

10:10 was hilarious!

[@robertklaassen2628]

But, if the Public address is fundamentally used to receive bitcoins. And if the Private key allows you to spend or transfer bitcoins stored at that address. Wouldn't the Private key also become public knowledge and subject towards being hacked ?...

[@AC-ew2xr]

HI I DONT UNDERSTAND THE DIFFERENCE BETWEEN A PRIVATE KEY AND A WALLET ADDRESS. I'M NEW TO THIS AND HAVE MY CRYPTO ON A HARD WALLET LEDGER..WHERE IS THE PRIVATE HEY? THERE'S NO INSTRUCTIONS ON THIS FOR ANYONE NEW! THANKS TO ANYONE WHO HELPS!

[@aantonop]

If you are using a Ledger hardware wallet, then your private key is represented by your mnemonic recovery seed (that string of 12 or 24 words you hopefully wrote down). That seed makes it easy to back up private keys because it is in a human-readable format. What you do with the private key is in the name: keep it private, don't share it with anyone unless you want to give them the ability to spend your funds! On the other hand, addresses are what you send and receive bitcoin to, and are meant to be shared. As an example, 1andreas... is one of my addresses. You could plug this or any other address into the 'Send' section form in your wallet. This address is associated with a private key that I hold, and only that private key could be used to spend funds from this address -- just as your addresses can only be spent from with your private key.

[@fiyinfoluwaoluwafemi1947]

Alex This man on instagram page kleencleff0102... He really helped me ... 😂😂👍

[@sandeepvk]

Question : Is is possible that two miners might complete a " proof of work " simultaneously ? If so who gets rewarded the "coin" ?

[@ziomanzo]

miner with longest chain wins. blocks need time to propagate trough the network. this happens a lot

[@DCUPtoejuice]

Can you tell how the private keys generated then become the keys used for the blockchain?

[@mariamalanana]

Professionalbitcoin7 on 1G gave me a private key

[@robertsWahlsVideos]

MATH ERROR in VIDEO: Isn't 10^77 / 10^9 = 10^68, not 10^65 as you say at around 8:45 of this video?

[@aantonop]

Fixed it in the subtitles.

[@landel_]

I know it's very, veeery improbable. Billions of people with trillions of computers until the end of universe and time as we know. But from time to time I generate a single key and check if there are any funds.

[@robertklaassen2628]

If the Public address is fundamentaly used to receive bitcoins. And if the Private key allows you to spend or transfer bitcoins stored at that address. Wouldn't the Private key also become public knowledge and subject towards being hacked ?...

[@angiesteele2141]

Robert Klaassen no there’s a particular strategy you use to beat that off

[@TheLinuxYes]

Math: can't live with it, Can't live without it.

[@Luk_men]

It possible to unlock vault, id like to spend it

[@donnellfms]

Which event is most likely to happen? Two people randomly picking the same Bitcoin private key or the emergence of a fully functional self-replicating cell within a toxic soup?

[@edwardwong654]

He has a good sense of humour too.

[@surendrashekhawat4155]

He didn’t even talked about uses of private key 😒

[@Prawn47]

10:28 Zing! hahahaha

[@TheLinuxYes]

1 Trillion seconds is approx 31,700 years.

[@ultrastoat3298]

10:10 savage

[@GregoryTKint]

10^77/10^9=10^65 ??? (8m50sec) I probably missed something but didn't Andreas just divide by 10^12

[@NanoMedia1]

I guess he made an error or omission of some sort. Should be 10^68

[@johnny14980]

Yeah maybe. Doesn’t really change his point tho

[@TheLinuxYes]

Andreas: what happens when an unstoppable force encounters an immovable object?? ((::

[@nion456789]

Smashed the like........

[@richieingoogleworld6524]

Love AA but would work much better with graphics/animation.

[@ericmilchak5101]

I hope everyone understood that....LOL

[@checkpoint209]

so in theory basically the guy from frisco who can’t remember his private key 🔑 and has 2 shots left to remember it holding 7000 bitcoin worth 240 million dollars is screwed

[@thetribe5054]

I have an even larger "issue". Its not really an issue.. but its supposed to be impossible to just guess a private key. Yet, i have. 6 times. 5 were 12 word mnemonics, which greatly reduces the large number range significantly, and all 5 might have also been intentionally chosen and then used, however, the 1... i guessed the 64 character hexidecimal ethereum private key of a used wallet, and has continued to be used since.. including a LARGE multimillion dollar tx. Without a computer. Im not saying this for any clout or whatever other bs people lie for, i just want someone, mainly you, to verify (if possible), or something to perhaps fix this... i dont even really know. :/

[@chocotv3573]

It sounds like you can't understand the private key without knowing the geometry or calculus.

[@crewstna5712]

Hi

[@altcoindaily7796]

Thanks to the team cyybererenacom for a job well done

[@Stonezster]

My head hurts...

[@Furlong157]

What?

[@gianluca.g]

If(andreas) likes++; first = true;

[@Molecularjewelry]

2027 is not so far away now with the rise of A.I.

[@cristenabbey3347]

You have good intentions, but you need to stop talking about elliptical curves and tangents because it's too difficult to understand.. If you really want to grow your channel, think of trying to explain bitcoin to a Labrador retriever. You will draw a large audience by explaining complicated subjects visually and in terms people can understand. Good luck

[@ClaytonBigsby01]

SO YOUR TELLING ME CHRISTIANS HAVE THE BEST CHANCE OF CRACKING THE CODE??!!!!lol

[@megtray5295]

Chris Harvey My wallet had 12btc which I could not have access to but thanks to *Hotz882* on Instagram. He got me the private key to my wallet at a small price..he will help you to

[@adeosunolumuyiwa6355]

I n n o v a t o r_t o o l s 0n IG he's a pro

[@balthasarbecker]

But Bitcoin is dead. It died so many times it is just impossible it survived .. :D

[@angiesteele2141]

Balthasar Becker bitcoin isn’t dead... only if you don’t believe in it... it’s a total way of life and survival ❤️

[@knourii]

Move back, u r too close to the camera , jesus