Bitcoin Forum

A few years ago, I created an electrum wallet on a desktop machine with version 1.8.1.

For reasons I won't go into here, I am now limited to the android client for the foreseeable future (and beyond).

I need to sign a message (not a transaction) with the private key associated with a specific bitcoin address in that wallet.

Two questions:

1. Is there any way of doing that?

2. If not, how do I export the private key into another wallet client, so I can sign a message with it?

I can miss the obvious sometimes, but I didn't see any way of doing either of these things.

I recently installed Electrum version 2.9.3 in my android cell phone, and I cannot find where can I make a sign message. Is there a way that I can make a sign message in this version? or this version has limited features.

Electrum client for Android doesn't have the feature to signed a message with your address, you can do it only on Desktop version of electrum, but if you are an android user I will suggest that use Mycelium mobile wallet, it does have the feature to signed message on any wallet address there, the one you created which is HD wallet and even the imported one but not the watched address.

When you make a wallet, you get a seed.
You can use this seed to get the private keys and master public key. This seed can be input in the desktop version downloadable here here (http://electrum.org/#download)

To ge the seed, click the panel at the top that shows how much your balance is and press "show seed", input your pin and type that seed into you computer electrum wallet.
From here you can then sign your address by clicking tools and then sign/verify message at the top.

No problem using Mycelium (wish they used the same word list as the Electrum version I used to create my wallet, though), but how do I get my private key out of Electrum on Android?



Uhm..., did you read what I wrote? I have no access whatsoever to any desktop version of Electrum. I need to get the private key out of the Android version.

Electrum wallet for Android is limited. You can't export private keys, and since Electrum uses a non standard derivation path you cannot restore the seed to another Android wallet like Mycelium. So find a laptop you can install Electrum on and restore the seed as you will never be able to do what you want with the Android version.

The only thing I can think of... is to make a couple of edits to the BIP39 mnemonic code converter (https://iancoleman.github.io/bip39/) and run that on your phone.

I hacked up a version of it that removes the checksum validation (Electrum uses a different system to BIP39 and I couldn't be bothered implementing it, so I just removed it ;D :P)... and uses "electrum" as the default passphrase (as per Electrum code) instead of "mnemonic" (as per BIP39 spec).

Electrum appears to use a "BIP32 Derivation path" of m/0 for receive addresses and m/1 for change addresses...

Also, because of the tremendous amount of JavaScript contained within the page... it is something like 2.5megs! And runs a bit slow on my old Galaxy S5, but it works ;)

I've put up a copy here: https://github.com/HardCorePawn/electrumBIP39

It's very rough, the links probably won't work, and half of it still references the iancoleman page, but I've put a test Electrum seed into it, and it generates the same receive and change addresses as the actual Electrum wallet.