How to sign a message?!

[Sethtabiah]

Wow, this is a great tutorial shorena! I think mods should sticky this, because every new user have to learn this basic thing before it's too late. I see a lot of users got hacked or lost password and they end up losing their account forever.

[MadGamer]

I finally learned what signing and verifying a message really means .
thank you so much shorena ,too  helpful

[zenitzz]

thank you this tutorial help me to signing and verifying a message

[bitbollo]

Hello, thank you for your exaustive guide, very strong and helpfull.
I have some question, first how can I "claim" an address here on btc talk?
And if I have related to me an address that is full of btc, if I sign a message I will show the private keys and potential can I lost the coins?
If yes, how can avoid this issues?

[--Encrypted--]

Hello, thank you for your exaustive guide, very strong and helpfull.
I have some question, first how can I "claim" an address here on btc talk?
And if I have related to me an address that is full of btc, if I sign a message I will show the private keys and potential can I lost the coins?
If yes, how can avoid this issues?

not sure if I understand your question there. you can't just "claim" any address. and you only need to use your private keys to generate the signed message, nobody will see it unless you included it on your message. so there's no risk of losing any coins.

[the_reprobate]

Hello, thank you for your exaustive guide, very strong and helpfull.
I have some question, first how can I "claim" an address here on btc talk?
And if I have related to me an address that is full of btc, if I sign a message I will show the private keys and potential can I lost the coins?
If yes, how can avoid this issues?

sign messages proves that you own a specific address and you don't need to show the private keys because you're potentially showing people how to get into your wallet. Just do the steps and show it to the person who is requesting it and this will prove that you own the wallet with funds

[shorena]

Just added multibit HD 0.1 as it was now officially replaced on their homepage[1]. Very nice wallet. It has no list of available addresses. Thus if you want to sign with a specific address just copy the address into the box.

link to pic: https://i.imgur.com/MtDpQjq.png

The signed message comes with a header, which you can remove.

Code:

-----BEGIN BITCOIN SIGNED MESSAGE-----
This is shorena from bitcointalk.org and today is 2015.06.22
this is a test for my "how to sign a message?!" thread.
-----BEGIN BITCOIN SIGNATURE-----
Version: MultiBit HD (0.1)
Comment: https://multibit.org
Address: 12U1ooM24WDLLeZokKejQbaYQFmX1Afpwu

INxr6O8CAb9AAvIYBIBJwYixjXudfIgxByY+ol++4gv9F9uctT4M8jznwVvmA/mDp7boSBv7hmZJUruXgtfk0hU=
-----END BITCOIN SIGNATURE-----

[1] https://bitcointalk.org/index.php?topic=1085503.0

[Amitabh S]

Can someone be fooled into creating a signature for an address that releases funds from that address?
(Or do tx signatures and "ordinary" signatures follow different encoding?)

[prodigy8]

Thanks shorena you helped me save hours of searching through the internet.

[Velkro]

Nice guide topic author, really helpfull. You did something good for bitocoin community "today"

[shorena]

Can someone be fooled into creating a signature for an address that releases funds from that address?
(Or do tx signatures and "ordinary" signatures follow different encoding?)

Im not 100% sure whether they are differently encoded, but my guess is that they are not. The message is just greatly different. Let me give you an example to make this clear. The following is my first raw transaction I created. I had to double spend it later because I did not pay a fee, so you cant find it on the blockchain. It was an attempt to fuse several spam TX into a single input. The TX is signed in its raw form and if you change a single bit the signature is invalid. Thus you cant have part of the message be a hidden transaction. You would need to convince someone to sign a very specific hex string like the "raw" below that makes little sense to a human. Additionally a TX might (as is the case here) need more than one signature.

formatted:

Code:

"[
{\"txid\":\"0c6c7de8c27a6bfe5c2e5e9a364bdbd2028194e25ba645bab91eae5668db10fa\",\"vout\":23},
{\"txid\":\"28d39206e2592bf02777831d839baa540137287936a3ee3f2b935bcccf7d2ee0\",\"vout\":4},
{\"txid\":\"4549b62fa61b0612ef6f06413b66d31cb454bfdccb2a12a2ca06e8e0a36c07b5\",\"vout\":1},
{\"txid\":\"cdd2d34071d548455d0b55130472006de2c048452ab96880e63feec619909797\",\"vout\":0}
]"
"{\"1MpNbGQrignRG9QKGbEQpz5uCg8KBJrQ9a\":0.0022}"

raw:

Code:

0100000004fa10db6856ae1eb9ba45a65be2948102d2db4b369a5e2e5cfe6b7ac2e87d6c0c1700000000ffffffffe02e7dcfcc5b932b3feea3367928370154aa9b831d837727f02b59e20692d3280400000000ffffffffb5076ca3e0e806caa2122acbdcbf54b41cd3663b41066fef12061ba62fb649450100000000ffffffff97979019c6ee3fe68068b92a4548c0e26d00720413550b5d4548d57140d3d2cd0000000000ffffffff01605b0300000000001976a914e45816c635fd7bfb567aa83c3980066c8de9046988ac00000000

and signed:

Code:

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

[misterycoins]

Very helpful tutorial ,awesomely simple explanation. thanks a lot

[bitcoinmar]

Very good work done by Shorena its helping many newbies to sign message and I have one question why this thread is not sticky can some one do this ?

[camelson]

Thanks shorena for these helpful topic, But can you please tell me How i can sign a message using BIT-X and BTC-e. Because im using their address. And i dont know I can sign a message

[shorena]

Very good work done by Shorena its helping many newbies to sign message and I have one question why this thread is not sticky can some one do this ?

Admins decide whether a thread gets stickied or not. Im not sure what the criteria for that are, but most stickies are about the forum and its rules.

Thanks shorena for these helpful topic, But can you please tell me How i can sign a message using BIT-X and BTC-e. Because im using their address. And i dont know I can sign a message

As they are not traditional wallets, but rather exchanges (+ extra in bit-x's case) I doubt you can sign a message with your deposit address. If they allow you to export the private keys you can use a local wallet to sign a message, but I doubt they do in the first place. I have no account for either service though.

[RealBitcoin]

Wow, this is a great tutorial shorena! I think mods should sticky this, because every new user have to learn this basic thing before it's too late. I see a lot of users got hacked or lost password and they end up losing their account forever.

Blockchain.info -> Receive address -> Select address -> Actions -> Sign message

If you are a newbie, dont consider using anything else than blockchain.info.

[shorena]

Wow, this is a great tutorial shorena! I think mods should sticky this, because every new user have to learn this basic thing before it's too late. I see a lot of users got hacked or lost password and they end up losing their account forever.

Blockchain.info -> Receive address -> Select address -> Actions -> Sign message

If you are a newbie, dont consider using anything else than blockchain.info.

Its a tad offtopic, but Ill bite. I would not recommend using blockchain.info at all, no matter if you are a newbie or not. Their service is constantly unreliable and/or offline. Blockchain.info offers nothing over a local wallet except that its accessible from everywhere, which is probably not a feature most people are looking for when its about their money. Even if its important than you can access your funds (or at least part of them) from everywhere, use an app for your smartphone.

Besides that, my impression is that Sethtabiah was talking about bitcointalk.org accounts, where a signed message can restore access to the account.

[Muhammed Zakir]

Bump.

[alberthendriks]

Can someone test my signed message? I don't really understand how it works, but this came out of the tutorial.

Code:

-----BEGIN BITCOIN SIGNED MESSAGE-----
This is alberthendriks from bitcointalk.org on 2015-07-07. I sign this message so I can later prove that I still have control over my account.
-----BEGIN SIGNATURE-----
13EDLzhBbe1aEmFfDRGsekw7iVs2e356o6
G7boxuY/0QhUZBIjwI/ESCgh26Kl/3N985H5lrJuRyipYt9Tm50s3h/gG10BbCFV7RxgZwXGS6ysi+Q60Kpgjqk=
-----END BITCOIN SIGNED MESSAGE-----

[alberthendriks]

To the dude who just read the above message and then tried to log in to my wallet: I have 2FA turned on and your ip is logged at two sites.