MD5 is the message digest algorithm (English: MD5 Message-Digest Algorithm). It is a widely used cryptographic function that transforms data (such as a paragraph of text) into another fixed-length value, which is the basic principle of hash algorithm and can generate a 128-bit (16-byte) hash value to ensure the integrity and consistency of information transmission.

MD5 was designed by Ronald Linn Rivest, an American cryptographer, and was published in 1992 to replace the MD4 algorithm. Where is the program of this algorithm? RFC 1321? Is regulated in.

after p>1996, it has been proved that there are weaknesses, which can be broken into pieces. For data that need high security, experts generally recommend using other algorithms, such as SHA-2. In 24, it was proved that MD5 algorithm could not prevent collision, so it was not suitable for security authentication, such as SSL public key authentication or digital signature. Extended data

Application of MD5 in reality

MD5 has been widely used in providing certain reliability for file transmission. For example, the server provides an MD5 checksum in advance. After the user downloads the file, the MD5 checksum of the downloaded file is calculated by the MD5 algorithm, and then whether the downloaded file is wrong can be judged by checking whether the two checksums are consistent.

MD5 is also used in some online casinos to ensure the fairness of gambling. The principle is that the system first generates the result of the game before the player makes a bet, and then encrypts the string of the result or a group of random strings by MD5, displays the encrypted string to the player before the player makes a bet, and then displays the unencrypted string to the player after the result is issued, so that the player can use MD5 tool to encrypt and verify whether the string matches.

resources

Baidu encyclopedia-MD5