Bitcoin is storable without reliance on, or assistance from, any trusted third-party such as a bank, financial institution or government. Instead, securing bitcoin relies upon unique cryptographic keys which can be kept independently by any user and used for sending and receiving batches of bitcoin. These unique keys are managed and accessed through a bitcoin wallet. This wallet manages shareable keys (the public keys) to which bitcoins are received, along with confidential keys (the private keys) from which bitcoins are sent.
The public and private keys work in pairs, similar to an account number and password, respectively. Just as transactions sent in the banking system are ‘locked’ to an account number and transferrable with a password, transactions in bitcoin are locked to a public key and transferrable with a private key. In an important distinction from the legacy financial system, where banks are needed to manage your accounts, in Bitcoin you may manage your own bitcoin wallets and you may be anonymous in doing so. But you can also choose a trusted third party to do it for you.
Today, Bitcoin infrastructure has evolved to the point where users rarely handle private keys themselves (they are large, inconvenient numbers). Instead, bitcoin wallets will typically provide a user with a ‘seed phrase’ that encodes the same information as private keys. A seed phrase is normally 12 to 24 common words randomly chosen from a bank of 2,048 words, making the phrases easier to remember and maintain.