Brute Force

[r-bitcoin]

If you backup your encrypted private keys to Dropbox, how long does your passphrase need to be (using only lowercase letters and numbers) to be safe from hackers?

[mocacinno]

If you backup your encrypted private keys to Dropbox, how long does your passphrase need to be (using only lowercase letters and numbers) to be safe from hackers?

If it's bip38 encrypted, it's actually pretty safe, even with a shorter password... however, i'd strongly advise to use a (very) strong password.
Read this thread for more info: https://bitcointalk.org/index.php?topic=1014202

Basically, this person created a bip38 encrypted paper wallet, encrypting the private key with the password "zLwMiR".
He then sent 1 BTC to the addres and posted the encrypted private key, the address and the fact that he only used a 6 letter password on this public forum. He also posted that the person who brute forced the password could spend the outputs (making brute forcing the password morally ok).

After 2 years, nobody managed to brute-force the password, so he closed the experiment.

[r-bitcoin]

What would be the difference between using Disk Utility on a Mac that has never been online for 256-bit AES encryption vs BIP38?

Thanks for your reply

[achow101]

What would be the difference between using Disk Utility on a Mac that has never been online for 256-bit AES encryption vs BIP38?

Thanks for your reply

BIP 38 is a standard format for encrypting Bitcoin private keys. This means that you can directly import a BIP 38 wallet into a wallet that supports BIP 38 so long as you can provide the correct password. Using an external encryption tool like Disk Utility means that you are encrypting files. This has the benefit of being able to encrypt your entire wallet (all of the private keys, addresses, and transactions that are yours) but also means that you can only use that wallet with the software that created it.