Base64 SHA1 MD5

Base64 Code

1:base64 is one of the most common encoding methods for transmitting 8Bit bytecode on the network, Base64 is a method of representing binary data based on 64 printable characters
2:BASE64 encoding is a process from binary to character that can be used to pass longer identity information in an HTTP environment
3: The encoded data is a string containing the characters: A-Z, A-Z, 0-9, +,/
A total of 64 characters: 26 + 26 + 10 + 1 + 1 = 64. is actually 65 characters, "=" is the padding character
4:64 characters need 6 bits to represent the value of 0~63

Base64 Coding Process

1: The string "Xue" becomes "WHVL" after Base64 encoding. The number of data bits with a length of 3 bytes is 8*3=24 and can be accurately divided into 6*4

2: If the number of bytes in the data is not a multiple of 3, then the number of digits is not a multiple of 6, then the need cannot be accurately divided into 6-bit blocks. At this point, you need to add 1 or 2 0-value bytes after the original data, so that the number of bytes is multiples of 3. Then, after the encoded string, add 1 or 2 equal sign "=" to indicate the number of 0 value bytes added. Cases:
The string "Xu" becomes "whu=" after Base64 encoding.

MD5/SHA1 Hash Algorithm

1:MD5 algorithm:
1> compressibility: Any length of data, the calculated MD5 value of the length are fixed.
2> easy to calculate: It is easy to calculate the MD5 value from the original data.
3>: Any changes to the original data, even if only modify 1 bytes, the resulting MD5 values are very different.
4> Strong anti-collision: Given the original data and its MD5 value, it is very difficult to find a data with the same MD5 value (that is, to falsify data).
2:SHA1 algorithm
and MD5 similar treatment;
3: Encrypt user password, server store user password is MD5 value;
4: Compare files whether there are changes, according to the contents of the file to generate MD5 value; Base64 Code

Base64 decoding

MD5

Online Calibration Tool

SHA1

Code