Of course there’s key distribution. Here are four ways keys can be distributed:
"KEY DISTRIBUTION FOR SYMMETRIC KEY CRYPTOGRAPHY
The major problem in symmetric key cryptography is that of the key distribution because the key must be shared secretly [2]. Keys can be distributed by any one of the following ways:
- Sender can select the key and physically deliver it to receiver.
- A trusted third party can select the key and physically deliver it to the sender and the receiver.
- If sender and receiver have previously and recently used a key, one party can transmit the new key to
the other, encrypted using the old key.
- If sender and receiver each has an encrypted connection to a third party, then the third party can deliver a key on the encrypted links to sender and receiver."
Reference:
Key Distribution for Symmetric Key Cryptography: A Review
–Konrad, WA4OSH