The security of symmetric encryption technology depends on the confidentiality of the key.

Symmetric encryption algorithm

Symmetric encryption (also called private key encryption) refers to an encryption algorithm that uses the same key for encryption and decryption. Sometimes called traditional cryptographic algorithms, the encryption key can be deduced from the decryption key, and the decryption key can also be deduced from the encryption key. In most symmetric algorithms, the encryption key and decryption key are the same, so this encryption algorithm is also called a secret key algorithm or a single key algorithm. It requires the sender and receiver to agree on a key before communicating securely.

The security of symmetric algorithms depends on the key. Leaking the key means that anyone can decrypt the messages they send or receive, so the confidentiality of the key is crucial to the security of communication. .

Characteristics of symmetric encryption algorithm

The characteristics of symmetric encryption algorithm are open algorithm, small calculation amount, fast encryption speed and high encryption efficiency.

The disadvantage is that both parties to the transaction use the same key, so security cannot be guaranteed. In addition, every time each pair of users uses a symmetric encryption algorithm, they need to use a unique key that is unknown to the other person. This will cause the number of keys owned by both senders and receivers to increase exponentially, and key management becomes a burden for users.

Symmetric encryption algorithms are more difficult to use on distributed network systems, mainly because key management is difficult and the cost of use is high. Compared with public key encryption algorithms, symmetric encryption algorithms can provide encryption and authentication but lack the signature function, which reduces the scope of use. Symmetric encryption algorithms widely used in computer private network systems include DES and IDEA. AES, advocated by the American National Bureau of Standards, will soon replace DES as a new standard.

The advantages of symmetric encryption algorithms lie in the high speed of encryption and decryption and the difficulty in cracking when using long keys. Assuming that two users need to use symmetric encryption to encrypt and exchange data, the users need at least 2 keys and exchange them. If there are n users in the enterprise, the entire enterprise will need n×(n-1) keys. The generation and distribution of keys will become a nightmare for enterprise information departments.

The security of the symmetric encryption algorithm depends on the storage of the encryption key, but it is impossible to require everyone who holds the key in the enterprise to keep the secret secret. They usually keep the secret secret intentionally or unintentionally. The key is leaked - if the key used by a user is obtained by an intruder, the intruder can read all the documents encrypted by the user's key. If the entire enterprise uses one encryption key, the entire enterprise's documents will be compromised. Confidentiality is out of the question.