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[ranochigo]

smartphone sounds like a smarter plan to me than a laptop.. it's much smaller and easier to conceal.

You can't be as secure since they might have vulnerabilities for generating keypairs like what happened a year ago. It isn't 100% safe, there is Always a risk about this.

[Meuh6879]

You can extract the private key and create and sign a raw transaction then broadcast it. The format would most likely still be accepted by the community. It is a good idea to stay in touch within the bitcoin community for updates.

  have you try this since this year (april 2014) ... ? many have evolved (smartphone backup wallet) with this IMPOSSIBILTY to restore.

that's why i have migrate from smartphone cold storage to bitcoin core cold storage ... file.

[arbitrage001]

The storage on phone might get corrupted.

A safer way is use Armory and print it out on a piece of paper.

[beetcoin]

The storage on phone might get corrupted.

A safer way is use Armory and print it out on a piece of paper.

storage on a computer can also get corrupted, can it not? designating an entire laptop to save your wallet takes up more space and is harder to hide/conceal too.

[shorena]

I've got one of these that I never use and I've wondered if it was a safe option.  I think I'll give this a try because I don't use it since I've got my pc.  Is it an issue if you have used it online before, does it matter if I have used it online not in airplane mode  in the past?  Does that somehow affect the integrity of the security?

Just reset to factory default before you do anything else and you should be fine IMHO.

The storage on phone might get corrupted.

A safer way is use Armory and print it out on a piece of paper.

storage on a computer can also get corrupted, can it not? designating an entire laptop to save your wallet takes up more space and is harder to hide/conceal too.

Todays phones are big

No seriously, armory is just the most secure client you can use AFAIK. So armory is safer, its just the question if you need that little more safety? E.g. I currenlty would not store >10 BTC on a phone, no matter if its offline or not.

I like the phone because its easier to setup and with a farady cage you can be certain its offline. Well removing the battery would also work.

[gtraah]

because backup file (from 2 years) don't work with the new client updated in the phone (since 1 hour) + private key are encoded ... (BIP something like that)

I dont understand what you mean?

I have Mycellium, I also have a Paper wallet with Public & Private Key I have copied this to soft copy to 2 different USBs... Now I also created an Encyrpted version on this Private Key with Mycellium and PRINTED it... All in an offline safe.

Now No matter how much times the client is updated I still have  the private key offline all I need to do is scan the key and BOOM I now have access to this wallet. I don't get what you mean you lost your cold storage file? I would never rely on a file related to one application, the most reliable is the unencrypted Private key from a normal BTC address, and an AWESOME hiding space. This means what ever , application you choose in future you have an address + priv key, no need for any wallet file or what ever. Mycellium is AWESOME as it concentrates on one address at a time, so if i want to ever take some money from my cold storage, i just scan the key .. take money out and then delete the key again. ALL the funds remain in the same address. None of this change address stuff which can cause paper wallets useless after usage.

[ranochigo]

You can extract the private key and create and sign a raw transaction then broadcast it. The format would most likely still be accepted by the community. It is a good idea to stay in touch within the bitcoin community for updates.

  have you try this since this year (april 2014) ... ? many have evolved (smartphone backup wallet) with this IMPOSSIBILTY to restore.

that's why i have migrate from smartphone cold storage to bitcoin core cold storage ... file.

Myceilum uses paper wallet technology, which will most likely still be supported after years. Bitcoin wallet uses wallet.dat which would very likely still be supported for years. You should be moving those BTC around every few years. Also, you should also stay in touch with the community, You would most likely still be able to get those BTC as there would still be supported software's to do so.

[oceans]

A phone would be too risky in my eyes as there is no way of you being able to prevent it totally from connecting to the internet. Notebooks are definitely what I would recommend as there are ways and means of you being able to prevent that completely from going onto the internet. You can pick up notebooks now for quite cheap as well.

[counter]

The only thing would be a risk is custom Roms. Some of them have backdoors but they cannot send data without internet so it can still be used as a cold storage. Always remove your SIM card first. Factory reset first then get the wallet then copy to somewhere safe and if you need to use it, factory reset it again.

Just reset to factory default before you do anything else and you should be fine IMHO.

Thanks for the feedback and advice. I'll be sure to do just that before I try to store any coins on the phone.

A phone would be too risky in my eyes as there is no way of you being able to prevent it totally from connecting to the internet. Notebooks are definitely what I would recommend as there are ways and means of you being able to prevent that completely from going onto the internet. You can pick up notebooks now for quite cheap as well.

This is also something worth considering but I'm not so sure how comfortable I would be using that for cold storage.  I'd rather store coins on a device I would not be using alot.  However if there is more security issues with the smartphone approach I would take that into consideration as well.