Symmetric Cryptography is a method of encryption where the same key is used for both encrypting and decrypting information. This means that both the sender and the receiver must have access to the same secret key to communicate securely. It is efficient for processing large amounts of data quickly. In symmetric encryption, common algorithms include AES (Advanced Encryption Standard) and DES (Data Encryption Standard). While it is fast and effective, the main challenge is securely sharing the key, as anyone with access to it can decrypt the messages.