Bitcoin Forum

It was mentioned here:
https://en.bitcoin.it/wiki/Mini_private_key_format
but it doesn't seem to be explained on the wiki. Is it just a base58 encoded private key, or is there more to it than that?

You mean "wallet import format" right?

To turn a normal private key into a WIF key you need to perform Base58Check encoding.

I'm pretty sure steps 4 to 9 on this page (https://en.bitcoin.it/wiki/Technical_background_of_Bitcoin_addresses) describe the process.
EDIT: btw, at step 4 you start with the private key and attach 0x80 to the front instead of 0x00.


I think this step is incorrect. The process completed between steps 4 and 9 is Base58Check encoding from what I understand. At step 9 you convert the result from a byte string into a base58 string using a specialized base58 character set: Base58 symbol chart (https://en.bitcoin.it/wiki/Base58Check_encoding#Base58_symbol_chart). On that same page you'll also see another step by step guide for Creating a Base58Check string (https://en.bitcoin.it/wiki/Base58Check_encoding#Creating_a_Base58Check_string).

To turn a public key into a bitcoin address it's the exact same process, except you need to start at step 1 instead of step 4. So you perform Base58Check encoding on the RIPEMD-160 hash.

Ok I see what you were referring to now:


I think that's actually meant to say "wallet import format".

Also have a look at this: Base 58 Wallet Import format (https://en.bitcoin.it/wiki/Private_key#Base_58_Wallet_Import_format)

The export/import wording can be used interchangeably.

That link is about creating a Bitcoin address from a key pair, not from the "wallet import/export format" which is said to "include built-in error checking codes" (from the "Private key" wiki entry).
The steps are correct for creating a Bitcoin address from a key pair, wrote that step-by-step guide myself, originally basing it off a public key used by Satoshi.
Didn't ask about turning a public key into a Bitcoin address, but turning the "wallet import/export format" into a private key. The rest I understand.

That Wiki page is a bit vague on the details as to how one should convert the WIF into a private key.

Steps 4 to 9 describe how to do Base58Check encoding (but remember what I said about step 9). A WIF (wallet import format) key is simply a Base58Check encoded private key.

EDIT: so let me make this clearer:

1) Attach '80' to start of private key.
2) Perform SHA-256 hash on the whole string.
3) Perform SHA-256 hash on the result of the previous SHA-256 hash.
4) Take the first 4 bytes of the last SHA-256 hash. This is the checksum.
5) Add the 4 checksum bytes from point 4 to the end of the string from point 1.
6) Convert the result from a byte string into a base58 string.

EDIT: If you look here (https://en.bitcoin.it/wiki/Base58Check_encoding#Creating_a_Base58Check_string) you'll see the process (Base58Check encoding) described in a few steps:

Okay, now I get it. You were just explaining things the other way around (private key -> import format), whereas I was trying to understand how to convert things back.

So in the end, to convert things from WIF to a private key, I would:
1) Convert the WIF into a hex array as any base58 encoded string
2) Drop the first byte and last 4 bytes

And I should also perform some checks to make sure the string wasn't corrupted by calculating the checksum.

Yeah I think that would be pretty much how to do it. Make sure to use the Base58 character set used by Bitcoin when doing the Base58 conversions.

Oh well, now it's all nice and explained:
https://en.bitcoin.it/wiki/Wallet_import_format
And I've also written a test suite:
http://gobittest.appspot.com/PrivateKey