What is a disadvantage of symmetric key cryptography?

The disadvantage of symmetric key cryptography is primarily related to key distribution. In symmetric key systems, the same key is used for both encryption and decryption, which means that both parties need to securely exchange and manage the secret key before communication can begin. If the key is intercepted or otherwise compromised during distribution, the security of the entire system is compromised. This necessity for secure key exchange can become a logistical challenge, especially as the number of participants increases, making it difficult to maintain a secure network of key holders.

In contrast, speed of encryption is generally not a disadvantage of symmetric key cryptography, as symmetric algorithms like AES are typically faster compared to asymmetric ones. The complexity of algorithms in symmetric cryptography tends to be lower than their asymmetric counterparts, which may involve more computational overhead. Finally, when it comes to resistance to attacks, symmetric cryptography, if implemented correctly, can be very robust against a variety of attacks, though the security does depend heavily on the secrecy of the key.