What is AES
For more knowledge about AES, please make up for it yourself. Advanced Encryption Standard (AES), also known as Rijndael encryption method, is a block encryption standard that is often used.
Go implements AES encryption
Golang's standard library aes can implement AES encryption. The official standard library aes document link: /crypto/aes
Small case requirements
This article shares the actual needs in actual work. The requirements are very simple, which is to implement a command line application that can encrypt incoming plain text strings and decrypt incoming ciphertext. The command line application is called passctl and has a help function. There are many powerful third-party libraries to implement command line applications. Because the requirements are too simple, this article just uses the Os in the standard library.
Actual combat
Encryption code
package main
import (
"bytes"
"crypto/aes"
"crypto/cipher"
"encoding/base64"
"fmt"
)
var EncKey = []byte("QAZWSXEDCRFVTGBY") // 16-bit password string
func pkcs7Padding(data []byte, blockSize int) []byte {
padding := blockSize - len(data)%blockSize
padText := ([]byte{byte(padding)}, padding)
return append(data, padText...)
}
func AesEncrypt(data []byte, key []byte) ([]byte, error) {
block, err := (key)
if err != nil {
return nil, err
}
blockSize := ()
encryptBytes := pkcs7Padding(data, blockSize)
crypted := make([]byte, len(encryptBytes))
blockMode := (block, key[:blockSize])
(crypted, encryptBytes)
return crypted, nil
}
func EncryptByAes(data []byte) (string, error) {
res, err := AesEncrypt(data, EncKey)
if err != nil {
return "", err
}
return (res), nil
}
func main() {
plaintext := "2wsx$RFV!Qaz" // Assume this is a plain text password p := []byte(plaintext)
newp, _ := EncryptByAes(p) // Start encryption (newp)
}
Decrypt the code
Decrypt the password based on the above encrypted password.
package main
import (
"crypto/aes"
"crypto/cipher"
"encoding/base64"
"errors"
"fmt"
)
var EncKey = []byte("QAZWSXEDCRFVTGBY") // 16-bit password string
func pkcs7UnPadding(data []byte) ([]byte, error) {
length := len(data)
if length == 0 {
return nil, ("Sorry, the encryption string is wrong.")
}
unPadding := int(data[length-1])
return data[:(length - unPadding)], nil
}
func AesDecrypt(data []byte, key []byte) ([]byte, error) {
block, err := (key)
if err != nil {
return nil, err
}
blockSize := ()
blockMode := (block, key[:blockSize])
crypted := make([]byte, len(data))
(crypted, data)
crypted, err = pkcs7UnPadding(crypted)
if err != nil {
return nil, err
}
return crypted, nil
}
func DecryptByAes(data string) ([]byte, error) {
dataByte, err := (data)
if err != nil {
return nil, err
}
return AesDecrypt(dataByte, EncKey)
}
func main() {
ciphertext := "+LxjKS8N+Kpy/HNxsSJMIw==" // ciphertext pwd, _ := DecryptByAes(ciphertext) // Start decryption (string(pwd))
}
Implement the passctl command line application
Code
package main
import (
"bytes"
"crypto/aes"
"crypto/cipher"
"encoding/base64"
"errors"
"fmt"
"os"
)
var EncKey = []byte("QAZWSXEDCRFVTGBY") // 16-bit password string
func pkcs7Padding(data []byte, blockSize int) []byte {
padding := blockSize - len(data)%blockSize
padText := ([]byte{byte(padding)}, padding)
return append(data, padText...)
}
func pkcs7UnPadding(data []byte) ([]byte, error) {
length := len(data)
if length == 0 {
return nil, ("Sorry, the encryption string is wrong.")
}
unPadding := int(data[length-1])
return data[:(length - unPadding)], nil
}
func AesEncrypt(data []byte, key []byte) ([]byte, error) {
block, err := (key)
if err != nil {
return nil, err
}
blockSize := ()
encryptBytes := pkcs7Padding(data, blockSize)
crypted := make([]byte, len(encryptBytes))
blockMode := (block, key[:blockSize])
(crypted, encryptBytes)
return crypted, nil
}
func AesDecrypt(data []byte, key []byte) ([]byte, error) {
block, err := (key)
if err != nil {
return nil, err
}
blockSize := ()
blockMode := (block, key[:blockSize])
crypted := make([]byte, len(data))
(crypted, data)
crypted, err = pkcs7UnPadding(crypted)
if err != nil {
return nil, err
}
return crypted, nil
}
func EncryptByAes(data []byte) (string, error) {
res, err := AesEncrypt(data, EncKey)
if err != nil {
return "", err
}
return (res), nil
}
func DecryptByAes(data string) ([]byte, error) {
dataByte, err := (data)
if err != nil {
return nil, err
}
return AesDecrypt(dataByte, EncKey)
}
const help = `
Help description of encryption and decryption command line application
-h --help [Display help]
-e --encryption Plaintext string encryption
-d --decrypt Ciphertext string decryption
Example:
1. encryption example:
passctl -e "your plaintext password"
2. decryption example:
passctl -d "Your ciphertext string"
`
func main() {
args := [1]
if args == "-h" || args == "--help" {
(help)
} else if args == "-e" || args == "--encryption" {
plaintext := [2]
p := []byte(plaintext)
newp, _ := EncryptByAes(p)
(newp)
} else if args == "-d" || args == "--decrypt" {
ciphertext := [2]
a, _ := DecryptByAes(ciphertext)
(string(a))
} else {
("Invalid option")
}
}
Use after compiling into binary
# Compilation[root@devhost encryptionDecryption]# go build -o passctl # View Help[root@devhost encryptionDecryption]# ./passctl -h Help description of encryption and decryption command line application -h --help [Display help] -e --encryption Plaintext string encryption -d --decrypt Ciphertext string decryption Example: 1. encryption example: passctl -e "your plaintext password" 2. decryption example: passctl -d "Your ciphertext string" # Encryption[root@devhost encryptionDecryption]# ./passctl -e abc123456 nGi3ls+2yghdv7o8Ly2Z+A== # Decryption[root@devhost encryptionDecryption]# ./passctl -d nGi3ls+2yghdv7o8Ly2Z+A== abc123456 [root@devhost encryptionDecryption]#
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