Your Sia seed is your key to your Siacoin balance, and in the future, it will be the key to your files as well. It’s the most important piece of information in your Sia experience.
It’s 29 words... most of the time. There's a small chance you'll get a 28-word seed.
It's generated when you first make your Siacoin wallet
It will also be your wallet password unless you set a custom password
If you have your correct seed, you can always recover your Siacoin balance.
If you lose your seed, your Siacoin balance will be permanently inaccessible. Because Sia is truly decentralized, the Sia dev team can’t access your seed at any time, for any reason.
If someone steals your seed, they can easily steal your Siacoin balance. Be wary of giving any untrusted third party your seed.
Because your seed is so important, you should have physical and digital methods of storing it safely. As with any piece of digital information that you care about, you shouldn't consider it safe unless you have multiple independent backups.
Store it the same way it's given to you: all lower-case letters, with a space between each word.
Make sure there is no space at the beginning or end of the seed.
Keep a laminated paper copy stored in a locked safe or a bank safe deposit box.
Keep your seed in a password or biometric (e.g. fingerprint) secured app like 1Password or LastPass.
Once you write it down, copy and paste it, or re-type it, make sure you've done so correctly. A single miswritten word or mistyped letter means the entire seed is incorrect, and can no longer be used to unlock your wallet or recover your Siacoin.
Your seed is your private key to your Siacoin balance, and it can also be used to unlock your wallet. The default setting is for your seed to double as your wallet password, but you also have the ability to set a custom password if you’d like. Because your seed is so long, it can function as an effective line of defense against someone gaining unauthorized access to your wallet. This isn’t the whole picture though, and there are other things you should consider before deciding whether to use your seed or a custom password to get in and out of your Siacoin wallet.
It would take modern technology trillions upon trillions of years to figure out a 20+ word phrase from scratch. This makes your seed a powerful deterrent against intruders if it doubles as your wallet password. But frequently typing your seed also makes you vulnerable to malicious software that might be installed on your computer. Let’s look at the pros and cons of each.
During wallet creation, you have an option to create a custom password for getting in and out of your wallet. You can also set this afterward at any point. This allows you to use something familiar instead of the wallet seed.