Explain the 2048 bit encryption.

From Digicert: https://www.digicert.com/ssl-cryptography.htm

"Public Key Infrastructure (PKI) uses a hybrid cryptosystem and benefits from using both types of" "(Asymmetric and Symmetric) encryption."
"Asymmetric encryption (or public-key cryptography) uses a separate key for encryption and decryption."
"Symmetric encryption (or pre-shared key encryption) uses a single key to both encrypt and decrypt data."
"Public-key cryptography (asymmetric) uses encryption algorithms like RSA to create the public and private keys." "RSA is based on the presumed difficulty of factoring large integers." "keys smaller than 2048 bits are no longer considered safe to use"; "would take an average computer more than 14 billion years to crack."
"Symmetric key sizes are typically 128 or 256 bits." "a 128-bit key has 340,282,366,920,938,463,463,374,607,431,768,211,456 encryption code possibilities"; "would take quite a bit of time to break a 128-bit key."

Summary: The 2048 bit encryption refers to the Asymmetric encryption offered by Digicert to transfer the 256-bit Symmetric key to facilitate the data exchange (secure communication) between the client & server (via SSL/TLS).