Example of correspondence between admin and user. To create such correspondence, activate the "Correspondence by key" option when creating the correspondence:

Once a conversation is created, the sender and recipient will receive a notification with a key that each participant must save.

User keys for accessing correspondence are stored on the server side for 7 days, after which they are deleted from the database FOREVER.
If, 7 days after the creation of the correspondence, the second party has not confirmed receipt of the access key, the key will be deleted, and the PM will remain encrypted FOREVER.
To encrypt the text of the PM, openssl_encrypt is used in the aes256ctr + sha256 mode with salt.

Once a conversation is created, the sender and recipient will receive a notification with a key that each participant must save.

User keys for accessing correspondence are stored on the server side for 7 days, after which they are deleted from the database FOREVER.
If, 7 days after the creation of the correspondence, the second party has not confirmed receipt of the access key, the key will be deleted, and the PM will remain encrypted FOREVER.
To encrypt the text of the PM, openssl_encrypt is used in the aes256ctr + sha256 mode with salt.