Topic: openssl making private/public keys for ethereum (Read 393 times)

Maybe this answer is not right for you because it's not about openssl. But people without heavy tech background trying to understand how secp256k1 works in ECC could use this guide. It helped me figure out things more or less https://yad.finance/blog/wallet-off-the-wall/

In short, this is what the process looks like:

1) Generate a private key using some degree of randomization. Along the lines of bitaddress.org or similar services.

2) Generate a public key from your private key using ECC (specifically the secp256k1 curve, which is a good fit for Ethereum).

3) Generate a public address out of the public key, which might also consist of generating a compressed public address, then refining this address, etc

Let me know if it helped

That's OK, I learnt stuff too
I used to know that it was possible to create a bitcoin key with openssl ecparam/ec and extract it from DER, but I didn't know that it was possible to rebuild a DER file from a key. I learnt that too today, and I'm pretty happy about it.

Have a nice day!

That works as expected thank you! I really appreciate you taking the time to send the updated code. If I ever get another spendable merit I'll send it your way. ;0)

To sum up, the steps are (I've compressed the whole procedure to a smaller command list):


You should be good this time. Could you check ?
Thanks you!

Ok, I guess it was incomplete.


That's because I imported the private key in the file, but the public key is still in there and openssl won't regenerate it (I thinked so, but well, it doesn't).

Let's make a valid file:


This said, my initial steps are just taking a long way. I could sum up the stuff, I guess.

Hmm. I need to take a deeper look, may be I missed a thing. Let me a few hours and I'll do some experiments. I'll let you know!

Well heck this doesn't work as expected. Run the keccak hash on the public key and the address doesn't match the wallet address for the private key according to myetherwallet.com. 

             cat Key | grep pub -A 5 | tail -n +2 |tr -d '\n[:space:]:' | sed 's/^04//' > pub

             cat pub | keccak-256sum -x -l | tr -d ' -' | tail -c 41 > address

Seems the public key produced belongs to the original key file created when this command was ran:
openssl ecparam -name secp256k1 -genkey -noout > private.key

But I'm still going to call you a genius b/c that hack was pretty clever and taught me some things I didn't know. :0)

You're a genius starmyc! Thank you for taking the time to explain this it works like a charm... Sent you the only sendable merit I had. ;0)

A tricky way to do this is to make use of DER files, and to recreate one to import your key. This is a little hacky, but it works.

This is how I did it in a few minutes:

1/ First, create a private key (you won't use, you just need the file structure) in PEM format:


We could directly create a DER file though, using a -outform DER, by the way.

1 (optional)/ What's cool about DER format is that you can dump in ASN.1 its structure. It is interesting and you should take a look at it:


2/ From the private.key PEM file, convert it in DER and extract the header, the key, and the footer.


3/ Replace the key I just created by yours


4/ Rebuild & check the complete DER file


See ? Same structure, different key! Voodoo magic!

5/ recreate your "Key" file:


And we're done.

I hope someone can help me with this… I'm asking in the bitcoin forum b/c question relates to secp256k1 & openssl.

I understand how to make an ethereum public/private key & public address using linux commands.
From the command prompt three simple steps:

1)                openssl ecparam -name secp256k1 -genkey -noout | openssl ec -text -noout > Key
2)                cat Key | grep pub -A 5 | tail -n +2 |tr -d '\n[:space:]:' | sed 's/^04//' > pub
3)                cat pub | keccak-256sum -x -l | tr -d ' -' | tail -c 41 >  address

Wala! All done! I’ve got a unique public/private key to use for my ethereum wallet.

But what I can’t figure out is how to input a set of numbers/letters into openssl and get the public/private keys like at the end of step 1.
Let’s say I like this ethereum private key but I need the public address to use it:

A114dad00000000000faced00000000000bad000000000decaf00c02bad02bad

I know I can go to an online wallet and enter the private key and get the public address which is:
0xB1607e934B61Fc1128AF1E8aa668e33d883aB3b9 (please nobody use this address keys are now public)
but I want to do this from linux prompt and get the answer.

My question: How do I enter that private key into openssl to get the private/public key pair returned something like this result?

Private-Key: (256 bit)
priv:
     0b:f3:29:aa:bf:d0:bb:0b:0f:e1:4b:80:54:f2:1a:
     2e:38:7d:cd:b5:9b:07:5f:3c:38:99:40:bd:5e:e4:
     a4:0f
pub:
     04:2f:06:55:11:4a:b1:90:11:00:a4:48:cb:6a:91:
     76:f3:01:50:2d:9f:8b:03:ab:cb:8b:67:e7:e7:d0:
     3f:85:de:e9:2a:76:59:12:94:4a:4a:ff:94:cd:d7:
     97:a2:6b:9c:ae:da:4e:ec:b0:1d:30:c0:55:14:90:
     b6:51:dd:75:09
 ASN1 OID: secp256k1   (please don’t use this key pair it’s now public)

Thanks in advance for any help… Openssl has really got me all messed up trying to figure this out.