A Blockcerts is directly associated with the recognition's owner. The Blockcerts contain a single identification number linked to the person. You must first generate the number in order to guarantee that it may be kept in your Blockcerts. 

This is what the App Blockcerts Wallet's definition of passphrase means. The passphrase that is maintained in your Blockcerts Wallet is a password that serves as your private key. Using this private key, a cryptographic process creates your public key, which is the number that you submit to Blockcerts. Your passphrase serves as your private key. Anyone may see your public key, but only you can authenticate your ownership of it.