#19unit 1technology solutions
Symmetric key encryption
Single shared key encryption and decryption.
Key-distribution problem in e-commerce
If 177 million U.S. e-commerce customers each needed a unique symmetric key with every merchant, potentially 177² million keys would be needed — far too unwieldy. This is the key-distribution problem that motivates public key cryptography.
AES (Advanced Encryption Standard) is the most widely used symmetric algorithm today, offering 128-, 192-, and 256-bit keys.