How to secure your Recovery seed or Mnemonic phrase?

[bitart]

What if you don't use password but use a cryptosteel kind of solution, but you cut your seed into half, and engrave the first part on one steel (it can be a steel business card, you can find it on eg. ebay) and the second part on another steel.

A half of a seed can be enough to crack the whole seed, depending on attacker's capabilities. Electrum seeds have 135 bits of entropy, and 67.5 bits can be cracked on modern hardware.

Plus, you are making things harder for yourself by having parts of your seed in different places. There are better schemes for that like Shamir's Secret Sharing or good old multisig - they even allow N of M parts setups, so you can account for risks of losing some of the parts of the wallet.

That's good to know, thank (the cracking of the seed)
Well, just make 3 or 4 parts and spread it
I know that's a bit oldschool solution, but I'm not familiar with that passphrase.
I know that Electrum has a possibility to use a password, also Trezor and maybe Ledger Nano has also something similar (Trezor for sure), but I don't know if they are cross compatible or not.
If you just want to store an amount in a wallet (even in a normal address not segwit etc... just the old style solution which is compatible with all kind of wallets for now and forever ) you don't want to use any possible incompatible solution just to increase the security.
Multisig is another good solution, I'll have a closer look at it, thanks

[bob123]

Well, just make 3 or 4 parts and spread it
I know that's a bit oldschool solution, but I'm not familiar with that passphrase.

A better solution regarding splitting the mnemonic code would be Sharmirs Secret Sharing.

With this algorithm, you are able to split your mnemonic code into unique sets, so that X out of Y parts (doesn't matter which exactly, just X out of Y) are required to construct the whole mnemonic.
That's definitely preferable to simply splitting it into pieces without the sharing scheme.

[Sourhearrt]

if you lost your recovery seed or private keys your funds are go forever,to avoid the mistake of losing your keys you should write down your keys somewhere safe and secured or buy a hardware wallet

[bob123]

if you lost your recovery seed or private keys your funds are go forever

And this exactly is the reason why OP asked how we secure our mnemonic code.

The question was not whether it is important to have a backup, but how to secure it.

to avoid the mistake of losing your keys you should write down your keys somewhere safe and secured or buy a hardware wallet

A hardware wallet doesn't mean you don't need a backup of your mnemonic code anymore.
Those devices can break too (just as a hard drive).

A backup of your mnemonic code / root key / whatever is always necessary, regardless of which kind of wallet you use.

[Successmaniac4]

I never knew the keyphrase can be recovered by a passphrase. I lost some of my money because I lost the keyphrase. But thanks to this information, u will not lose my money anymore.

[ezeobulu007]

I have a note book where I jot down all of my recovery/mnemonic phrases after that I take a picture and save them in my gallery vault app so I can only access it.

[prix]

And you shouldn't trust encrypted archives either.
WinRAR, for example, implemented the encryption itself correctly, but used a 4 bit IV.
Any encrypted archive can be decrypted within a few minutes.

I don't know whether this has been fixed already, but such a huge mistake is just embarrassing.

I tried to search for '"4 bit IV" winrar' in the google - there is only your post. I looked a little at the whole on Winrar password vulnerabilities - nothing.
Can you tell me more about what you are talking about?

[bob123]

I tried to search for '"4 bit IV" winrar' in the google - there is only your post. I looked a little at the whole on Winrar password vulnerabilities - nothing.
Can you tell me more about what you are talking about?

There have been multiple vulnerabilities already.
WinRAR used its own encryption mechanism before implementing standard (good) algorithms.

However, the vulnerability i was referring to actually was from 7zip. Sorry, my bad.
They used a 16 byte IV (instead of 128 byte as defined in the standard) of which 8 byte were 0's, so effectively a 8 byte IV.

This hasn't been found for several years.
Relying on WinRAR, WinZIP or 7zip for storing confidential information is always a bad idea. If you want to encrypt data, use some good and reputable software which is made for doing so (e.g. VeraCrypt).

[prix]

However, the vulnerability i was referring to actually was from 7zip. Sorry, my bad.
They used a 16 byte IV (instead of 128 byte as defined in the standard) of which 8 byte were 0's, so effectively a 8 byte IV.

Ok. Thanks for the link. And I’ll fix it a bit, it's about 128 bits, not bytes. Half of 128 bit zeros.
And it doesn't look like a strong vulnerability, 64 bits of RNG is still a lot.

[sima_sara]

What if you don't use password but use a cryptosteel kind of solution, but you cut your seed into half, and engrave the first part on one steel (it can be a steel business card, you can find it on eg. ebay) and the second part on another steel.

A half of a seed can be enough to crack the whole seed, depending on attacker's capabilities. Electrum seeds have 135 bits of entropy, and 67.5 bits can be cracked on modern hardware.
....

How is this possible? 

[Saint-loup]

Which is why some schemes allow you to add password to your seed, so the seed alone is not enough to access the wallet, because private keys are derived from both the seed and the password. I personally don't use this method, because I use Electrum and it doesn't have this option, but even if I could, I still wouldn't because it just adds just the complexity of storing password somewhere. I'd rather not risk locking myself out of my coins because of a misplaced password.

I think Electrum wallet also has the feature of Passphrase. Instead of storing your password anywhere, you can choose a strong password which you can remember. Even if the seed is stolen, without the passphrase they cannot access the wallet.

You can choose to keep part of your funds under passphrase(large amount) and fewer amount without a passphrase(small amount). If the wallet is stolen, then only the small amount without a passphrase will be lost. You can still save the large amount of funds.

Usually people don't own one single wallet only, they possess several wallets with several seeds and even several lonely private keys belonging to one particular address they've used to receive a payment or signing a message for example. So what is your advice when you have several seeds precisely? Do we need to use one single passphrase for all of our wallets or do we need to change it and to use a different one for each of our seed/wallet? Using a passphrase could also be dangerous because if you forget it you will lose your funds even if you have the seed, which can be heavily frustrating.