Topic: successfully using old phone for cold storage now (Read 2384 times)

I have been using this without incidents since I made it and its a stand alone, "offline", portable, hand held QR generator and offline cold storage. I dont have to use 2 or more offline devices to generate and save 2key/address, It saves me the dependency of having to be tied to a PC.  I can generate addresses on the road and load funds onto that address with one.

Dont get me wrong, I like paper wallets, and a paper wallet is a fine idea to me, In fact you could even print an offline paper wallet straight from this totally offline generating device, .  I like any viable means that allows an individual to retain their private keys, including paper wallets

If it all comes down to your safe deposit box, you could just as well use a paper wallet. Or even better: an encrypted paper wallet.
Both https://bitcoinpaperwallet.com/ and https://www.bitaddress.org/ can easily create encrypted paper wallets, BIP38 encryption is very hard to brute-force with any decent password.

I get that you like the project, nothing wrong with some experimenting, but for real-world savings, I wouldn't use this.

I dont see it having any total advantage over a paper wallet or vice cersa, . I view them both as good possible methods of cold storage, . . Currently I am using this device, and if I want a paper wallet, I can take my SD card backup and simply put it onto an offline printer and print a paper wallet out for myself without ever having to go online.

I agree with you.
Phones are kinda susceptible for attacks..
A Hardware wallet would be definetly safer..
With your phone you only can spend/access your coins in a safe environment..
Thats the advantage of Hardware wallets.. you can use them on compromised Computers.

But overall i rly like the idea for (kinda) small amounts) 

How about the risk of your phone internal storage crashing or becoming corrupted?

I know you are backing up the stuff already, but what advantage do you have over a paper wallet at that time in the way you described it (theft). The backup could still be compromised.

I personally would still go for a hardware wallet, but the phone would work as well I guess.

I have wifi bluetooth disabled , airplane mode, and the sim card removed, and it never goes online anymore as far as I can tell, . i've been using it lately, . It totally off line generates its own QR code/2key bitcoin addresses, scans and displays selected QR's, codes for funding in and out of the cold storage wallet And backs up all my keys offline to the external SD card.   . more about it here, . .  https://www.reddit.com/r/Bitcoin/comments/5vpn48/an_open_source_generic_offline_linux_qr2key/ ,    and here, . . https://www.youtube.com/watch?v=0LTu59a5IJA

Phone is never a good idea for cold storage. It has Wifi, bluetooth, 2G/3G/LTE cellular.

I'm sure you are fine but I wouldn't use it to store large amounts of BTC.

if its a large amount of BTC that you would want to hang on to for a while I would probably use the trezor or paper, i can not totally justify the validity of my project yet nor how it will work on all phone brands, . all i can say is that it is working well right now for me, but i am still running it through testing, .i ran $5 into and out of it successfully without it having any online connections, . now i am loading it with $27 to further test the portability of it and the ease of use with personal in person trades on the street, . . next after that I will be loading more if it all looks good and use one for permanent invested and holdings of larger amounts of BTC, while using a second cold wallet as my personal portable on the fly shopping cold wallet, . just say'n, . dont jump into it with out further looking into it and trying it out, . at least it is easy to look into as old phones are often laying around and the apps to put on it are free, . I have a post on this also on reddit, which has further comments and ideas , . .let me know if you do it though, and how it goes, and any problems or improvements you encounter, that would be much appreciated, and thanks

A great idea and something that I have been looking at over the past weeks. I want to keep the small amount I have accumulated so far safe and was reading about trezor, It struck me that I have an old nokia windows phone which is still perfectly working on my desk.

I now have some inspiration

I will add also best to remove internal phone sim card, . from an old phone lying around to offline qr generator and wallet in 15 minutes

I have successfully bought $5 worth of bitcoin with a debit card using a coinbase account, then used an old offline phone to generate a bitaddress with public and private keys, transferred the money from coinbase to the cold wallet account on the before said cold phone with all wifi, bluetooth, mobile data transfer etc disabled, saved all public and private key data to an sd card., then used the cold offline phone wallet to check balance of funds in previously created bitcoin account online using qr code from screen, . . and then transfered cold wallet funds back online to my Mycelium wallet, . . . Very easy to do once I figured it out.

Why? . . I am seeing various advantages to this over a paper wallet. one is security. . suppose I have funds on a paper wallet in my house, or I am using it to go to a coffee shop to make a transaction, . . suppose my house is robbed (yes I can keep paper wallets in a safe deposit box) , so suppose on the way to make a transaction at a coffee shop that my paper gets lost, (I stupidly drop it or my wallet gets pick pocketed) , or my house gets robbed. . with a paper wallet. . who ever finds the paper can immediately transfer funds, . so once i get to the coffee shop and realize i have lost the paper, by the time i go back home and get the backup info, the funds have had plenty of time to be transferred. . where as if i lost my cold phone wallet, the theif or luck person finding it must first unlock my phone with the screen unlock pattern, then passwords, encryption, etc, . giving me plenty of time to go back and get my backup and transfer those funds away myself first, . I also can backup all my info using a usb cord to an offline computer or sd card and also print paper copies myself, . then store those backups in a safe deposit box.

How I did it. . . I used my wifes old samsung sch1200 that was laying around the house. (she loved that phone) . It is in excellent working condition and the battery holds an excellent charge,. especially since it is no longer transmitting data, . this phone also has an external sd card slot

  1. I did a factory reset on it to restore it to original condition and to remove all previously installed programs

  2. Used the wifi to get online from a place i considered secure

  3, I had to update google play store and enter a valid google account

 4 downloaded apps from the play store.  "opera mini web browser", "QRDroid"

  5. Using Opera mini I went to bitaddress.org and saved the page for offline use

  6. took phone offline by halting wifi and bluetooth and putting it in airplane mode. (if you are still worried you can probably root the device etc.)

  7. while offline I opened Opera and opened the bitaddress page i saved offline and generated a bitcoin account with keys, (this was a frustrating part and i learned during the random mouse generation to touch and swipe up)

  8. after generating an account I held down on the character string that was generated for the public key and with the option told it to share that to qrDroid, Then told qrDroid to save it. .  (did the same for the private key,)  I then also copied the character string to a word processor for an additional backup method and record keeping.

  9. opened qrDroid and went to the options and opened up history, opened up the public key and choose the show qr option, . using that qr I transferred the funds from coinbase onto the cold wallet account, then used the same qr code online to check the account, . both of these were done with my online phone, . the account balance showed a successful transfer, . .

  10. opened up qrdroid and put the cold wallet qr private code on screen, then using my online phone scanned the qr and tranferred those funds to my Mycelium account.

  11.  backed up my data and put my totally offline cold wallet phone away

  just saying after alot of trying different apps it can now be easily done, i can back up data onto paper and sd card and put it in a safe deposit box, i can keep my cold storage at home knowing it has passwords and confidential swipes and or encryption to open, and I can now make a second always blank one to take to the coffee shop for transactions with nothing on it but the current single qr code i want to use.  

  I am somewhat new at bitcoin so if anyone knows where I am going wrong or finds any issues please let me know, . .also you can donate I hope if i do this right at 1PGaNWs6ccLZF2QMu1WyV235nNetjRZgUw