The best Base64 encoding and decoding tutorial in the whole network, with 6 examples!

base64 Encoding can convert binary data to text format , And can transmit data on any communication medium .

There are many coding application scenarios , For example, e-mail encryption .

Base64 Method is usually a binary to text encoding scheme , It said 8 Byte binary data to ASCII String format , When transferring or bootstrapping data between various media , There are many advantages , Especially for text support .

according to Base64 Representation table , Binary data can be converted to 64 Different species ASCII character , This conversion is easy to transmit and print .

Using letters A To Z、a To Z、0 To 9 and + and /, in total 64 individual ASCII Character to represent from 000000 To 111111 Binary system , Each non final Base64 The number just stands for 6 Bit data .

Base64 Index table

Bash base64 Encoding and decoding

grammar

base64 [ Parameters ] [ Input file ] [ The output file ]

• Parameters ： The parameters are as follows .
• Input file ： You can input from the standard （ Command line ） Or file .
• The output file ： You can redirect output to standard output , Such as terminal or file .

（1） Parameters -e or –encode ：

Used to encode any data from standard input or any file , Is the default option .

（2） Parameters -d or –decode ：

Used to decode any encoded data from standard input or any file .

（3） Parameters -n or –noerrcheck

By default ,base64 Errors are checked when decoding any data , have access to –n or –noerrcheck Option to ignore the check when decoding .

（4） Parameters -i or --ignore-garbage

Used to ignore non alphabetic characters when decoding .

（5） Parameters -u or -help

Used to get information about the usage of this command .

Example 1 – Basic coding

stay Linux in , Default installation base64 package , therefore , You can easily use it from the command line , To simply encode a string or text , You can pipe it to the command line and get the encoded text .

In the following example , character string wljslmz.cn Encoded as base64.

echo "wljslmz.cn" | base64

Output ：

d2xqc2xtei5jbgo=

explain

The encoding method uses several steps to transform the input ：

• The input character is converted to 8 Bit binary value
• The entire set of binary strings is split into 6 Bit binary value
• Convert to decimal
• Each decimal value passes through base64 The index table is converted to base64 character

Example 2 – Basic decoding

To decode a string , Just use parameters –decode Pass the encoded value to base64, It decodes the string just entered .

echo "d2xqc2xtei5jbgo=" | base64 --decode

bash base64 Encoding and decoding

Example 3 – Code text file

You can use the same command to encode a text file and redirect the output to another text file ：

base64 wljslmz.txt  > wljslmz-encode.txt

Code text file

Example 4 – Decode text file

To decode use base64 Encoded text file , Just use –decode or -d Switch and pass the text file name .

base64 -d wljslmz-encode.txt

Example 5 – Encode custom input from the user

Use bash shell Programming , You can get input from the user through the terminal and encode it , But to do this, you need to write a simple shell Script and execute it after granting executable rights .

The following examples can be used as a reference ：

#!/bin/bash
# Welcome to the O & M talk ！！！
# You can enter wljslmz.cn
echo " Please enter base64 Encoded character ：:"
read input_text
output_text=`echo -n $input_text | base64`
echo "Base64 Characters after encoding : $output_text"

Custom input – Using scripts base64 Encoding and decoding

Example 6 – Use base64 Simple authentication for

Use the above encoding and decoding methods , You can implement a simple authentication system .

You can ask the user to enter a password or password , Then the password is stored in a file or dynamically compared , If the stored encoding string matches the encoded text entered by the user , Then the user passes authentication .

This is a very simple method of authentication , Sometimes useful for simple business cases .

#!/bin/bash
# Welcome to the O & M talk , This is a simple script , use base64 code 
# Use debugpoint.cn For example 
echo " Verify your password "
read pwd1
decoded_text=`echo 'd2xqc2xtei5jbg==' | base64 --decode`
if [[ $pwd1 == $decoded_text ]]
then
    echo " Hello, master ！"
else
    echo " You're a bad guy , Verification failed ！！！"
fi

Let's try this script ：

summary

Above, we have introduced in detail through several examples base64 The principle and use of coding , It must be as long as you look at the above , There must be gains , It is better to move your heart manually , Now let's open the command line , Knock madly .