Commonly used encryption algorithms are as follows:

DES encryption algorithm

DES encryption algorithm is a block cipher, which encrypts data in groups of 64 bits. Its key length is 56 bits, and the encryption and decryption use the same algorithm. DES encryption algorithm keeps the key secret, while public algorithms include encryption and decryption algorithms. In this way, only people who have the same key as the sender can interpret the ciphertext data encrypted by DES encryption algorithm. Therefore, the decoding DES encryption algorithm is actually the encoding of the search key. For a 56-bit long key, if an exhaustive search is used, the number of operations is 256.

With the continuous development of computer system capabilities, the security of DES is much weaker than when it first appeared. But from a non-critical point of view, it can still be considered sufficient. But DES is only used to identify the old system now, and more is to choose the new encryption standard.

AES encryption algorithm

AES encryption algorithm is an advanced encryption standard in cryptography. The encryption algorithm adopts symmetric block cipher system. The minimum key length supported is 128,192,256, and the block length is 128 bits. The algorithm should be easy to implement in various hardware and software. This encryption algorithm is a block encryption standard adopted by the US federal government. This standard is used to replace the original DES, and it has been widely used in the world after many analyses.

AES encryption algorithm design supports 128/ 192/256 bits (/32=nb) data block size (i.e. packet length); The password length of 128/ 192/256 bits (/32=nk) is supported, which corresponds to 34× 1038, 62× 1057, 1.6038 in the basic system.

Rsa algorithm

RSA encryption algorithm is the most influential public key encryption algorithm at present, and it is generally considered as one of the best public key schemes at present. RSA is the first algorithm that can be used for both encryption and digital signature. It can resist all known password attacks so far and has been recommended by ISO as the public key data encryption standard. RSA encryption algorithm is based on a very simple number theory fact: it is very easy to multiply two large prime numbers, but it was wanted at that time, but it was extremely difficult to factorize their products at that time, so the products can be made public as encryption keys.

Base64 encryption algorithm

Base64 encryption algorithm is one of the most commonly used coding methods for transmitting 8-8 byte codes on the network. Base64 encoding can be used to transmit long identification information in HTTP environment. For example, in HIBEMATE (a JAVAPERSISTENCE system), Base64 is used to encode a long unique identifier into a string, which is used as a parameter in HTTP forms and HTTPGETURL. In other applications, it is usually necessary to encode binary data into a form suitable for putting in a URL (including hidden form fields). At this time, using Base64 coding is not only short in time, but also unreadable, that is, the encoded data will not be directly seen by the naked eye.

MD5 encryption algorithm

MD5 is a widely used hash function in the field of computer security, which is used to protect the integrity of messages. The simple description of MD5 encryption algorithm can be as follows: MD5 processes the input information in 5 12 bit packets, and each packet is divided into 16 32-bit packets. After a series of processing, the output of the algorithm consists of four 32-bit data packets, which will generate a hash value of 128 bits after concatenation.

MD5 is widely used in password authentication and key identification of various softwares. MD5 uses hash function, and its typical application is to generate an information digest for a piece of information to prevent it from being tampered with. The typical application of MD5 is to generate fingerprints for messages to prevent messages from being tampered with. If there is a third-party certification authority, MD5 can also prevent the "denial" of the document author, which is the so-called digital signature application. MD5 is also widely used in login authentication of operating systems, such as UNIX, login passwords of various BSD systems, digital signatures and many other aspects.

SHA 1 encryption algorithm

SHA 1 is a message digest algorithm as popular as MD5. SHA encryption algorithm imitates MD4 encryption algorithm. SHA 1 is designed for digital signature algorithm (DSA).

SHA 1 is mainly applicable to the digital signature algorithm defined in the digital signature standard. SHA 1 will generate a message digest of 160 bits for messages less than 2 "64 bits in length. When a message is received, the message digest can be used to verify the integrity of the data. During transmission, the data is likely to change, so different message digests will be generated at this time. SHA 1 cannot recover information from the message digest, and two different messages will not generate the same message digest. In this way, SHA 1 can verify the integrity of data, so SHA 1 is a technology to ensure the integrity of files.

SHA 1 encryption algorithm can use no more than 264 bits of data input and generate a summary of 160 bits. Input is divided into blocks of 5 12 bits and processed separately. The 160 bit buffer is used to store the intermediate result and the final result of the hash function. The buffer can be represented by five 32-bit registers (A, B, C, D and E). SHA 1 is a more secure algorithm than MD5. Theoretically, all digital authentication algorithms that adopt the "message digest" method have "conflicts"-that is, the message digests calculated by two different things are the same, which is the case with the interoperability deception graph. However, it is difficult for high-security algorithms to find the "collision" of specified data, and it is even more difficult to calculate the "collision" with formulas-so far only MD5 has been cracked in general security algorithms.

Encryption algorithm is the core of cryptography. These encryption algorithms are commonly used, and some of them have been cracked, some are unsafe, some have unknown strength, some need further analysis, and some need further research. In the mysterious world of encryption algorithms, new members will join in, expecting the birth of more secure algorithms.