128 bit & 256 bit are key lengths used to encrypt and decrypt files in a symmetric encryption. Symmetric encryption uses a single key for encrypting and decrypting data, and both a sender and a receiver needs the same key to secure a connection.
The numbers are fixed based on the Advanced Encryption Standard (AES) as established by US National Institute of Standards and Technology (NIST) in 2001.
128-bit encryption is said to be sufficient for security as it will take combinations to break the key and thousands of years to crack the code.
256-bit encryption, on the other hand, is a longer key that provides a higher margin of security in encryption and decryption, with combinations needed to break the key.
In today’s industry standards, 256-bit encryption is widely used in symmetric encryption and provided by Certificate Authorities (CAs) in the issuance of SSL certificates. Cracking a 256-bit key encryption will take twice as long as a 128-bit key encryption, which is 1,000,000 years needed virtually.
Strongest Encryption Used
By default, DigiCert uses 256-bit encryption key for all its digital certificates in symmetric encryption and purchasing a DigiCert certificates means you’re guaranteed one of the most secured encryption techniques used.