600 word seed

[Dabs]

12 or 24 words is more than enough.

If you are a target, specifically, where is your 600 words saved or stored and do you have access to it? It can be "hacked" with a $5 wrench attack.

There is no one on this planet I know who would not give up his bitcoin wallet when threatened with physical violence (either them or someone they know), so if you've got your physical security covered, go ahead and have fun with 600 words.

I would just use dice, I bought a set of 100 6-sided dice of different colors.

As for seed words, the words should not be "familiar", they should be randomly generated either by the computer or dice or coin flips.

[BrewMaster]

As for seed words, the words should not be "familiar", they should be randomly generated either by the computer or dice or coin flips.

it is always best to stick to the standards which means choosing words from the predefined wordlist that BIP39 uses too. this way in a couple of years when you wanted to recover your seed you won't have to also remember the customized method that you chose and the dictionary you used and end up losing your bitcoin to something that simple.

[HCP]

Also i dont save 600 word seed i only save few key pairs. Thats all i need

So you are effectively reducing your security to "only" the security of a standard bitcoin private key... You've really gone to an awful lot of trouble to simply generate a couple of private keys

It's like taking a taxi around the block to get to the house next door... you could have just walked

[pooya87]

So you are effectively reducing your security to "only" the security of a standard bitcoin private key.

Security of bitcoin private keys are 128 bits since the security of Elliptic Curve keys are defined as half the key size (bitcoin curve is 256 bit). On the other hand security of entropy (if generated randomly and is strong) is the same as its size. If the 600 words are selected using the same word list as BIP39 with 2048 words then their security is 600*11=6,600 bits. A pointless increase but an increase nonetheless.

[o_e_l_e_o]

So you are effectively reducing your security to "only" the security of a standard bitcoin private key...

Even if he did write down his 600 word seed and never looked at his private keys, his security is still 128 bits. It doesn't matter what ridiculous thing he does with his seed phrase; his keys will never be more secure than 128 bits.

All these things you can do your seed phrase - force it to be 600 words, additional passphrases, etc. - might increase the physical security of your seed phrase if it means an attacker has to compromise two or more back ups instead of just one, but the cryptographic security of your private keys remains 128 bits.