None of the following are "cold wallets":
save wallet dat file . . .
Thats all it takes just saving your wallet.dat? . . .
only way would be transfer them to a computer wallet, then transfer your dat file . . .
. . . You can use advanced options tab in blockchain . . .
How about encrypting . . .
If you use a service like Coinbase . . .
. . . go on blockchain . . .
Use wallets like myceilum . . .
At worst, a cold wallet is a wallet that is not and never has been accessible from the internet.
At best, a cold wallet:
- Was generated with a source of randomness that is guaranteed to have at least 160 bits of entropy.
- The private keys and addresses are calculated on an operating system that itself has never been connected to the internet.
- No address that has value associated with it has ever received an output that has been spent.