What does md5 code mean?

The md5 code is a 128-bit feature code obtained by mathematically transforming the original information based on the public MD5 algorithm. This feature code is irreversible and highly discrete; the md5 code is usually used for passwords Encrypted storage, digital signatures, file integrity verification, etc.

The operating environment of this article: Windows7 system, DELL G3 computer

What does the md5 code mean?

MD in MD5 stands for Message Digest, which means message digest. However, this message digest is not an abbreviation of the message content, but a 128-bit (bit) feature obtained by mathematically transforming the original message according to the public MD5 algorithm. code.

This feature code has the following characteristics. First of all, it is irreversible. For example, I have a secret text such as: "My Secret Words". After algorithm transformation, I get the MD5 code (b9944e9367d2e40dd1f0c4040d4daaf7). Tell other people about this code. There is no systematic way for them to know what your original text is based on this MD5 code.

Secondly, this code is highly discrete, that is to say, a small change in the original information will lead to a huge change in MD5, such as "ABC" MD5 (902fbdd2b1df0c4f70b4a5d23525e932) and "ABC" (one more Space) MD5 (12c774468f981a9487c30773d8093561) are very different, and there is no relationship between them, which means that the generated MD5 code is unpredictable.

Finally, since this code is 128 bits long, the possibility of having the same MD5 code between any messages is very low and is generally considered impossible.

So it is generally believed that MD5 code can uniquely represent the characteristics of the original information and is usually used for encrypted storage of passwords, digital signatures, file integrity verification, etc.

MD5 Message-Digest Algorithm:

MD5 Message-Digest Algorithm (English: MD5 Message-Digest Algorithm), a widely used cryptographic hash function that can generate A 128-bit (16-byte) hash value is generated to ensure complete and consistent information transmission. MD5 was designed by American cryptographer Ronald Linn Rivest and made public in 1992 to replace the MD4 algorithm. The procedure for this algorithm is specified in RFC 1321. After 1996, it was confirmed that the algorithm has weaknesses and can be cracked. For data requiring high security, experts generally recommend using other algorithms, such as SHA-2. In 2004, it was confirmed that the MD5 algorithm cannot prevent collisions, so Not suitable for security authentication, such as SSL public key authentication or digital signatures.

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