Lost blockchain password but have wallet backup and password memonic. What to do

[barcombeboy]

Hello,

I am sorry for the dumb question but I don't understand the Help notes at Blochain.info and very worried I'll do the wrong thing.

My password for my Blockchain wallet is not being accepted and I can't work out if/how I can access my wallet.
I have a local wallet backup and also the password recovery memonic.

Can anyone tell me how I can best gain access to my wallet? Please bear in mind that I am pretty inexperienced at this and do not have a good grasp of Bitcoin matters.

Any help appreciated. Thanks.

---------------------------

A subsidiary matter....
I can't access my Blockchain wallet via my phone either. My 4 number pin is not accepted. This is quite worrying as I am certain I am using the pin (and also the password) i registered with.

I have some vague memory that Blockchain changed the wallert addresses at some point (I have had a wallet there for a year or two but never really used it) and wonder if this might been something to do with it. I've also had reports of two unconfirmed deposits for tiny amounts into my account (but not done anything about them).

[Coef]

Hello,

I am sorry for the dumb question but I don't understand the Help notes at Blochain.info and very worried I'll do the wrong thing.

My password for my Blockchain wallet is not being accepted and I can't work out if/how I can access my wallet.
I have a local wallet backup and also the password recovery memonic.

With the "Mnemonic Phrase", you could get back the wallet identifier and password in the following page.
https://blockchain.info/wallet/forgot-password?

[barcombeboy]

I have the identifier but was not certain if that page would let me reset the password or not. If it does, i'll try it. Thanks very much.

[Coef]

I have the identifier but was not certain if that page would let me reset the password or not. If it does, i'll try it. Thanks very much.

You are welcome.
That page should give you the current password, and you can reset it after logging in.

[Kprawn]

I thought they said, they do not save any passwords on their servers?

[Coef]

I thought they said, they do not save any passwords on their servers?

Not sure about the details (haven't checked mnemonic.js myself), but it seems the mnemonic is just an encoding of your password.
So, bc.i doesn't save your password, but is able to decode the "mnemonic" when you enter it in the "forget password page" and get back your password.

How exactly is it implemented?  What strength does the mnemonic provide (bits etc)?  I assume you are using the electrum seed encoding (interactive en/decoder at brainwallet)?

It is almost the same encoding as electrum but with the addition of a checkum and version byte. https://github.com/blockchain/My-Wallet/blob/master/mnemonic.js the entropy provided will be the same as the password itself, the mnemonic will grow or shrink depending on the length of the password.

My concern is that there is an addition of another way to decrypt my wallet (or worse, my password itself).

It recovers the password itself.

[JohnFromWIT]

https://blockchain.info/wallet/security

Password Policy
Your password is never transmitted over the internet, sent to our servers, stored in cookies or in your browser's local storage in any form for this reason we are unable to help recover lost passwords.

Then how does the mnemonic recover the password, if they don't have it?

[DannyHamilton]

https://blockchain.info/wallet/security

Password Policy
Your password is never transmitted over the internet, sent to our servers, stored in cookies or in your browser's local storage in any form for this reason we are unable to help recover lost passwords.

Then how does the mnemonic recover the password, if they don't have it?

Because the mnemonic IS the password.  They don't have it, but if you have the mnemonic, then you do.

As a simple example, imagine that you have a password like:

"TQBFJOTLD"

Then, imagine you create an mnemonic:

"The quick brown fox jumps over the lazy dog".

Even if you forget your password, you can recover it from the mnemonic.  All you need is the mnemonic rule (first letter of each word).  But anyone with the rule "First letter of each word" can't figure out what your password is unless they also have your list of mnemonic words.

In the case of blockchain.info, the mnemonic rule is much more complex than "First letter of each word", but regardless, there is a mnemonic rule, and they know what the rule is.  That rule is useless to them for figuring out your passphrase since they don't have the list of mnemonic words.  So blockchain.info sends your browser the software to apply the mnemonic rule, and you provide the list of words to that software.  Then the software is able to convert the mnemonic to the password in your browser and tell you what it was.

If you understand Javascript, you can see the source of the program (and the entire wordlist) here:
https://blockchain.info/Resources/wallet/mnemonic.js

(Scroll to the bottom to see their complete word list)

[JohnFromWIT]

https://blockchain.info/wallet/security

Password Policy
Your password is never transmitted over the internet, sent to our servers, stored in cookies or in your browser's local storage in any form for this reason we are unable to help recover lost passwords.

Then how does the mnemonic recover the password, if they don't have it?

Because the mnemonic IS the password.  They don't have it, but if you have the mnemonic, then you do.

As a simple example, imagine that you have a password like:

"TQBFJOTLD"

Then, imagine you create an mnemonic:

"The quick brown fox jumps over the lazy dog".

Even if you forget your password, you can recover it from the mnemonic.  All you need is the mnemonic rule (first letter of each word).  But anyone with the rule "First letter of each word" can't figure out what your password is unless they also have your list of mnemonic words.

In the case of blockchain.info, the mnemonic rule is much more complex than "First letter of each word", but regardless, there is a mnemonic rule, and they know what the rule is.  That rule is useless to them for figuring out your passphrase since they don't have the list of mnemonic words.  So blockchain.info sends your browser the software to apply the mnemonic rule, and you provide the list of words to that software.  Then the software is able to convert the mnemonic to the password in your browser and tell you what it was.

Insightful as ever,
That makes perfect sense.
Thanks Danny

[ShakyhandsBTCer]

If you have the password memornic you can simply enter it on the right were it says "recover wallet' and enter the memonic, it will then display your password for you.