Verify Message fails

[onedrop]

Verify message fails when attempting to verify a message signed by geth. I believe this has something to do with the 'Ethereum Signed Message' prefix that geth adds.

[tayvano]

Can you please send example of what geth outputs / you are trying to verify. Thank you!

[onedrop]

in geth console do this...

• web3.eth.sign(web3.eth.accounts[0], web3.sha3('fubar'))
• take the output of that command and build a json like so...
• {"address":"<my_address>", "msg":"fubar", "sig":"<result_of_above_command>"}
• paste that into the form here https://www.myetherwallet.com/signmsg.html...

The result is a red "Invalid signed transaction" message.

Verification works properly on https://etherscan.io/verifySig

[crptm]

@onedrop can you generate one for me? :)

[onedrop]

ok here...

{"address":"0xaaff40fa1bb528905d626b78a67b7a019f63f5bf", "msg":"fubar", "sig":"0x36b7a6de3a0ff8ba7520c31ee022dbdfd369bd7887d610b70353a5e9e9e56d9016b9c3512f443f0d683eca4bc9a173c86d0851cd9ce8aff5543591dc1859bdfa1c"}

If it helps, it appears that geth prepends the string \x19Ethereum Signed Message:\n<length of message> to the data before signing it.

[lacabra]

For the record, different supported wallets by MyEtherWallet sign messages differently, so it matters which wallet you use, and as @onedrop reports above some are not compatible with the standard that Ethereum uses (geth, etherscan, etc). My current observations are that Metamask and Ledger are fully compatible, MEW's keystore/private key is mostly compatible (but it breaks on some types of inputs) and Trezor signs it using its own way (see this thread: ethereum/go-ethereum#14794).

So if you are expecting something that works across the board, you will be disappointed :(

[tamaile]

im also here icant verify my contrract address