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License check code snippets

golang

(tested on version 1.11.5)

package main

import (
	"encoding/base64"
	"encoding/json"
	"fmt"
	"golang.org/x/crypto/ssh"
	"log"
	"time"
)

var pubKey = `ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAAAgQC4dK1cTSWe/6IkGpB8Xqc8YEFUKPLDFvl37Or4WacQhIhH+yb7dKAae0t866/ViZHf6qjwuWD4iXhmmQm5hDS9yiGGjEzmovhW8PiuJ7qhdkuliBbWmn5knOT9A4b9QSNubsVhk5qGExbK9hoFLR/97fqeCsuy67jvhXABPh7fBQ==`
var lic = "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"

type signed struct {
	License   string        `json:"license"`
	Signature ssh.Signature `json:"signature"`
}

type article struct {
	Name string `json:"name"`
}

type license struct {
	LicensedTo string     `json:"name"`
	LicType    string     `json:"type"`
	Start      time.Time  `json:"start"`
	End        *time.Time `json:"end"`
	Articles   []article  `json:"articles"`
}

func checkLicense(prodId, pubKey, licString string) *license {
	pub, _, _, _, e := ssh.ParseAuthorizedKey([]byte(pubKey))
	die(e)
	var sl signed
	bytes, e := base64.StdEncoding.DecodeString(licString)
	die(e)
	e = json.Unmarshal(bytes, &sl)
	die(e)
	e = pub.Verify([]byte(sl.License), &sl.Signature)
	die(e)
	var lic1 license
	e = json.Unmarshal([]byte(sl.License), &lic1)
	if e == nil {
		if time.Now().After(lic1.Start) {
			if lic1.End == nil || time.Now().Before(*lic1.End) {
				for _, a := range lic1.Articles {
					if prodId == a.Name {
						return &lic1
					}
				}
			}
		}
	}
	return nil
}

func main() {
	const prodId = "PRODID-test"
	lic1 := checkLicense(prodId, pubKey, lic)
	fmt.Printf("License verified: %t\n", lic1 != nil)
	if lic1 != nil {
		fmt.Printf("You have %s license for product \"%s\" registered to %s.\n", lic1.LicType, prodId, lic1.LicensedTo)
	}
}

func die(e error) {
	if e != nil {
		log.Fatal(e)
	}
}

python 3

(tested on version 3.6.4)

import base64
import json
import re
from datetime import datetime, timezone

# pycryptodome
from Crypto.Hash import SHA256
from Crypto.PublicKey import RSA
from Crypto.Signature import PKCS1_v1_5

pub_key = 'ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAAAgQC4dK1cTSWe/6IkGpB8Xqc8YEFUKPLDFvl37Or4WacQhIhH+yb7dKAae0t866/ViZHf6qjwuWD4iXhmmQm5hDS9yiGGjEzmovhW8PiuJ7qhdkuliBbWmn5knOT9A4b9QSNubsVhk5qGExbK9hoFLR/97fqeCsuy67jvhXABPh7fBQ=='
lic_str = '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'


def date_decode(s):
    if s is None:
        return None
    pat = re.compile(r'^(\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\+\d{2}):(\d{2})$', re.M | re.I)
    m = pat.match(s)
    if m is not None:
        s = m.group(1) + m.group(2)
        return datetime.strptime(s, "%Y-%m-%dT%H:%M:%S%z")
    return s


def check_license(prod_id, pub_key, lic_string):
    sl = json.loads(base64.b64decode(lic_string))
    rsakey = RSA.importKey(pub_key)
    signer = PKCS1_v1_5.new(rsakey)
    digest = SHA256.new()
    digest.update(bytes(sl['license'], 'utf8'))
    sign = sl['signature']['Blob']
    try:
        signer.verify(digest, bytes(sign, 'utf8'))
    except ValueError:
        return None
    lic = json.loads(sl['license'])
    now = datetime.now(tz=timezone.utc)
    if now > date_decode(lic['start']):
        if lic['end'] is None or now < date_decode(lic['end']):
            arts = lic['articles']
            for i in range(len(arts)):
                a = arts[i]
                if prod_id == a['name']:
                    return lic
    return None


prod_id = "PRODID-test"
lic = check_license(prod_id, pub_key, lic_str)
print("License verified: %s" % (lic is not None))
if lic is not None:
    print("You have %s license for product \"%s\" registered to %s.\n" % (lic['type'], prod_id, lic['name']))

php

(tested on version 7.3)

<?php
// phpseclib 1.0
include('Crypt/RSA.php');


$pub_key = "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAAAgQC4dK1cTSWe/6IkGpB8Xqc8YEFUKPLDFvl37Or4WacQhIhH+yb7dKAae0t866/ViZHf6qjwuWD4iXhmmQm5hDS9yiGGjEzmovhW8PiuJ7qhdkuliBbWmn5knOT9A4b9QSNubsVhk5qGExbK9hoFLR/97fqeCsuy67jvhXABPh7fBQ==";
$lic_str = "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";

function check_license($prod_id, $pub_key, $lic_string) {
    $sl = json_decode(base64_decode($lic_string));
    $rsa = new Crypt_RSA();
    $rsa->setPublicKeyFormat(CRYPT_RSA_PUBLIC_FORMAT_OPENSSH);
    $key_created = $rsa->loadKey($pub_key);
    if (!$key_created)
	return null;
    $rsa->setSignatureMode(CRYPT_RSA_SIGNATURE_PKCS1);
    $signature = base64_decode($sl->signature->Blob);
    $verified = $rsa->verify($sl->license, $signature);
    if (!$verified)
	return null;
    $lic = json_decode($sl->license);
    $now = time();
    if ($now > strtotime($lic->start)) {
        if ($lic->end === null || $now < strtotime($lic->end)) {
            $arts = $lic->articles;
            foreach($arts as $a) {
                if ($prod_id == $a->name)
                    return $lic;
            }
        }
    }
    return null;
}


$prod_id = "PRODID-test";
$lic = check_license($prod_id, $pub_key, $lic_str);
echo "License verified: " . ($lic !== null ? "true" : "false") . "\n";
if ($lic !== null)
    echo "You have " . $lic->type . " license for product \"$prod_id\" registered to " . $lic->name . ".\n";

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