What are the conventional encryption algorithms?

In the field of data encryption and decryption, algorithms are divided into two types: symmetric keys and asymmetric keys. Due to their respective characteristics, symmetric keys and asymmetric keys are used in different fields. Symmetric key encryption algorithms are generally used to encrypt overall data due to their fast speed, while asymmetric key encryption algorithms have good security performance and are widely used in the field of digital signatures.

DES Encryption Algorithm

DES encryption algorithm is a block cipher that encrypts data in 64-bit blocks. Its key length is 56 bits. Encryption and decryption Use the same algorithm. The DES encryption algorithm keeps the key secret, and the public algorithm includes encryption and decryption algorithms. In this way, only someone who has the same key as the sender can decipher the ciphertext data encrypted by the DES encryption algorithm. Therefore, deciphering the DES encryption algorithm is actually a search for the encoding of the key. For a 56-bit key, if the exhaustive method is used to search, the number of operations is 256.

With the continuous development of computer system capabilities, the security of DES will be much weaker than when it first appeared. However, based on the actual non-critical nature, it can still be considered sufficient. However, DES is now only used for authentication on older systems, and is more often used for new encryption standards.

AES encryption algorithm

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AES encryption algorithm is cryptography The advanced encryption standard in the encryption algorithm uses a symmetric block cipher system. The minimum supported key lengths are 128, 192, and 256, and the block length is 128 bits. The algorithm should be easy to implement on various hardware and software. This encryption algorithm is the block encryption standard adopted by the U.S. federal government. This standard is used to replace the original DES. It has been analyzed by many parties and is widely used around the world.

The AES encryption algorithm is designed to support 128/192/256 bits (/32=nb) data block size (i.e. packet length); supports 128/192/256 bits (/32=nk) password length, , in decimal notation, corresponds to 34×1038, 62×1057, and 1.1×1077 keys.

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RSA encryption algorithm

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The RSA encryption algorithm is the most influential public key encryption algorithm at present, and is generally considered to be one of the best public key schemes at present. RSA is the first algorithm that can be used for both encryption and digital signatures. It is resistant to all cryptographic attacks known so far and has been recommended by ISO as a public key data encryption standard. The RSA encryption algorithm is based on a very simple fact of number theory: it is very easy to multiply two large prime numbers, but then it is extremely difficult to factor their product, so the product can be exposed as an encryption key.

Base64 encryption algorithm

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The Base64 encryption algorithm is one of the most common encoding methods used to transmit 8-bit byte codes on the Internet. Base64 encoding can be used to transmit long identification information in an HTTP environment. For example, in the JAVAPERSISTENCE system HIBEMATE, Base64 is used to encode a long unique identifier into a string for use as parameters in HTTP forms and HTTP GETURL. In other applications, it is often necessary to encode binary data into a form suitable for placement in a URL (including hidden form fields). At this time, using Base64 encoding is not only shorter, but also unreadable, that is, the encoded data will not be directly visible to the naked eye.

MD5 encryption algorithm

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MD5 is in the field of computer security A hash function widely used to provide message integrity protection. A brief description of the MD5 encryption algorithm can be as follows: MD5 uses 512-bit groups to process input information, and each group is divided into 16 32-bit sub-groups. After a series of processing, the output of the algorithm consists of four 32-bit sub-groups. Composed of bit groups, concatenating these four 32-bit groups will generate a 128-bit hash value.

MD5 is widely used for password authentication and key identification in various software. MD5 uses a hash function, and its typical application is to generate a message digest for a piece of information to prevent it from being tampered with. A typical application of MD5 is to generate a fingerprint for a message to prevent it from being "tampered with." If there is a third-party certification agency, using MD5 can also prevent "repudiation" of the file author. This is the so-called digital signature application. MD5 is also widely used for login authentication of operating systems, such as UNIX, various BSD system login passwords, digital signatures, and many other aspects.

SHA1 encryption algorithm

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SHA1 is the same as MD5 The same popular message digest algorithm. The SHA encryption algorithm mimics the MD4 encryption algorithm. SHA1 is designed for use with the Digital Signature Algorithm (DSA).

SHA1 is mainly applicable to the digital signature algorithm defined in the digital signature standard. For messages less than 2"64 bits in length, SHA1 will produce a 160-bit message digest. When the message is received, this message digest can be used to verify the integrity of the data. During transmission, the data is likely to be changes, then different message digests will be generated at this time. SHA1 cannot restore information from the message digest, and two different messages will not produce the same message digest. In this way, SHA1 can verify the integrity of the data, so SHA1 is a technology designed to ensure file integrity.

The SHA1 encryption algorithm can take no more than 264 bits of data input and produce a 160-bit digest. The input is divided into 512-bit chunks and processed individually. The 160-bit buffer is used to save the intermediate and final results of the hash function. The buffer can be represented by five 32-bit registers (A, B, C, D, and E). SHA1 is a more secure algorithm than MD5 , in theory, any digital verification algorithm that adopts the "message digest" method will have a "collision" - that is, the message digest calculated by two different things is the same, as is the case with the interoperable cheating graph. But an algorithm with high security needs to It is difficult to find the "collision" of specified data, and it is even more difficult to calculate the "collision" using formulas - so far, only MD5 has been cracked among the general security algorithms.

XXXTEA Encryption Algorithm

"The Tiny Encryption Algorithm (TEA) and its related variants (XTEA, Block TEA, XXTEA) are block cipher algorithms that are easy to describe and simple to implement (typically a few lines of code).

The TEA algorithm was originally designed in 1994 by David Wheeler and Roger Needham at the Cambridge Computer Laboratory. The algorithm uses a 128-bit key to encrypt a block of information with a 64-bit key, and it requires 64 iterations. The algorithm uses a mysterious constant δ as a multiple, which is derived from the golden ratio to ensure that each round of encryption is different. But the precise value of δ does not seem to be important. Here TEA defines it as δ = "(√5 - 1)231" (that is, 0×9E3779B9 in the program). ”

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Encryption algorithms are the core of cryptographic technology. The above encryption algorithms are commonly used encryption algorithms. Some of these algorithms have been deciphered, some are not secure, some have unknown strengths, some need further analysis, and some require in-depth analysis. Research, and new members will join the mysterious world of encryption algorithms, looking forward to the birth of more secure algorithms.

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