The OpenSSL RSA private key contains all the elements needed to recreate the public key from it. [0] Explains it in more detail.
You create the private key on the client side so that you can encrypt it with a custom password before sending it to Backblaze. Doing this makes they key recoverable from you - as long as you remember the passphrase to decrypt it - and unusable from Backblaze.
You create the private key on the client side so that you can encrypt it with a custom password before sending it to Backblaze. Doing this makes they key recoverable from you - as long as you remember the passphrase to decrypt it - and unusable from Backblaze.
[0] https://stackoverflow.com/a/26048132/2080636