safe store bitcoins on simless smartphone

[goode400]

I have read a lot about security and it seems to be the Achilles heel of bitcoin. I read about the Trezor, which sounds like a great idea but it occurred to me that a cheap smartphone would do the same job if the sim card is removed as soon as the bitcoins are in the wallet.

Any thoughts?

Apologies if this has already been discussed.

[1714649263]

1714649263

[vesper39]

So you are essentially storing the wallet private key on either the sim card or the memory card of the phone? In that case, you don't even need the phone really... Sounds the same as storing it on a usb stick no?

[Bitbuy]

So you are essentially storing the wallet private key on either the sim card or the memory card of the phone? In that case, you don't even need the phone really... Sounds the same as storing it on a usb stick no?

Yes, USB backup could do this as well... plus, why would the old cellphone (functioning as a USB stick) need the SIM?

[apetersson]

it is a good idea, especially if you have a solid ROM, like an updated stock rom, or better Cyanogenmod.

Tons of people are doing this with the Mycelium Wallet, since it runs really well on limited resources.

For the truly paranoid, you can even combine this with BIP38 cold storage spending from paper wallet and you have a pretty secure setup.

[Rannasha]

So you are essentially storing the wallet private key on either the sim card or the memory card of the phone? In that case, you don't even need the phone really... Sounds the same as storing it on a usb stick no?

You could use the phone to sign transactions (and display the QR code of the signed transaction to be scanned by a networked machine). A USB stick can't do that.

[goode400]

If I wanted to spend bitcoins I could just put the sim card back in.....Or would there even be a security risk in connecting for a few minutes?

[Rannasha]

If I wanted to spend bitcoins I could just put the sim card back in.....Or would there even be a security risk in connecting for a few minutes?

In theory? Yes. Malware could be on the phone waiting for a network connection to broadcast your private key. In reality, the odds of this happening are extremely small, but any device that goes online, even briefly, is in principle a security risk.

[railzand]

so one of my phones has no sim and just uses wifi. if i turned that off, would be better than usb?

[goode400]

so one of my phones has no sim and just uses wifi. if i turned that off, would be better than usb?

or ipod touch?

[Bitbuy]

so one of my phones has no sim and just uses wifi. if i turned that off, would be better than usb?

or ipod touch?

Well, the only added benefit I see would be the use of a wallet app, so you can manage the wallet from the phone...

[hilariousandco]

Don't most phones need a sim in to be active? I know older phones wouldn't let you do anything but call emergency services unless a sim was plugged in. I can't say I've noticed with the iphone whether it works with or without a sim, and mine is stuck in so I can't get it out to try it. But yeah, if this works it could be a good idea.