Your Wallet & Its Master Seed
When you create your Blockchain Wallet, a unique master seed is created. This master seed is the nucleus of your specific wallet, and is used to derive every individual bitcoin address that you'll use to send and request bitcoin.
Client Side Encryption Means Only You Have Access to Your Wallet
We do not store your bitcoins, we only provide you with the software you need to store them yourself. Your wallet is encrypted on your device with your personal password. Your password acts as your decryption key to both lock and unlock your wallet — your wallet cannot be accessed without it. Because we don’t know or store your password (we can’t even reset it), only you are able to unlock and decrypt your wallet.
We've Got Your Back(up)
Your encrypted wallet is automatically backed up to our servers. To safely store your wallet, we add another layer of security by encrypting your wallet a second time. Securely storing your wallet on our servers ensures that you can access your wallet from any (and all) of your different devices.
Decrypting your wallet couldn't be easier
When you access your wallet with your Wallet ID (a unique identifier specific to your wallet) and password, your browser uses our API to download your encrypted wallet backup, before safely decrypting it on your device.
Your Backup Phrase - The Failsafe
Your Backup Phrase is made up of 12 random words, and is an encoded version of your master seed (and an industry standard). It acts as a backup and allows you to access your bitcoins and ether regardless of the wallet software you’re using. In the event that you lose your password, or choose to use another wallet provider, your Backup Phrase is all you need to regain access to your funds.
We cannot (and don't want to): view your balance, view your address book, make transactions on your behalf, confiscate your wallet, or lock you into our service.
We run regular internal & external security audits, to keep your wallet safe.
We have an internal QA team dedicated to the highest quality bug-free products.
Our bug bounty program, which rewards security researchers for helping us find and fix bugs in our software, ensures that our wallet is tested thoroughly.
Our codebase is open source for everyone to check (take a look).