foo.go

package main

import (
	"crypto/aes"
	"net"
)

func EncryptIp(key []byte, ip net.IP) net.IP {
	cipher, err := aes.NewCipher(key)
	if err != nil {
		panic(err)
	}
	encrypted_ip := ip.To16()
	cipher.Encrypt(encrypted_ip, encrypted_ip)
	return encrypted_ip
}

func main() {
	key := []byte("example key 1234") // must be 16 bytes
	ip := net.IPv4(93, 184, 216, 3)
	encrypted_ip := EncryptIp(key, ip)
	println(encrypted_ip.String())
}