According to the different types of keys, modern cryptography can be divided into two categories: symmetric encryption algorithm (secret key encryption) and asymmetric encryption algorithm (public key encryption).
Symmetric key encryption system uses the same key for encryption and decryption, and both parties must obtain this key and keep it secret.
The encryption key (public key) and decryption key (private key) used in asymmetric key encryption system are different.
1) symmetric encryption algorithm
DES (Data Encryption Standard): A high-speed data encryption standard, which is suitable for encrypting a large amount of data.
3DES(Triple DES): Based on DES, a piece of data is encrypted three times with three different keys, which is more powerful.
AES (Advanced Encryption Standard): Advanced encryption standard, which is the next generation high-speed and high-security encryption algorithm standard;
2) Asymmetric encryption algorithm
RSA: Invented by RSA Company, it is a public key algorithm that supports variable-length keys, and the length of the file block to be encrypted is also variable.
DSA (Digital Signature Algorithm): Digital signature algorithm, which is a standard DSS (Digital Signature Standard);
ECC (Elliptic Curve Cryptography): Elliptic Curve Cryptography.
3) One-way encryption algorithm
Strictly speaking, BASE64 is an encoding format, not an encryption algorithm.
MD5 (Message Digest Algorithm 5).
sha 512
Hash message authentication code
Two. characteristic
DES, 3DES, AES AES encrypts data, and there is only one password with different key lengths.
PBE's password-based encryption is based on password encryption, and the password user is responsible for it, without any physical media, and adopts random number hash multiple encryption to ensure data security.
RSA can be used for both user data encryption and digital signature, and has a public key and a private key. The significance of digital signature is to check the transmitted data and ensure that the data is not modified during transmission.
In one-way encryption, MD5, SHA and HMAC are irreversible encryption, and one-way hash is generally used to generate information digest. Usually used as the basis of encryption. One-way encryption is mainly used to check whether it has been modified during transmission.
3. Algorithm comparison
In management, public key cryptography can achieve its goal with less resources, and there is an exponential difference in key distribution between them (one is N and the other is n2). Therefore, private key cryptography algorithm is not suitable for wide area network, and more importantly, it does not support digital signature.
In terms of security, it is almost impossible to crack the public key cryptography algorithm because it is based on unsolved mathematical problems. For the private key encryption algorithm, it is theoretically impossible to crack in AES, but from the perspective of computer development. Public keys have more advantages.
-In terms of speed, the software implementation speed of AES has reached several megabytes or tens of megabytes per second. It is 1000 times of the public key, and if it is implemented by hardware, the proportion will be expanded to1000 times.
Fourth, reference
/support/ssl_DES.html