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Software licensing using digital signatures 🪪

License++ is a cross platform software licensing library that uses digital signatures to secure use of your application and its licensing.

Abstract

I created a concept of digital software licence and implemented it under this project. The digital licence would be issued by an issuing authority with a digital signature. The whole process is protected by public-key cryptography signing scheme. This guarantees that the generation of new licenses is restricted, and any attempts to tamper with an issued license are prevented, similar to how we are issued with driver's licence, or better.

Features

• RSA-Based signing to prevent alteration
• Custom license keys for your software
• Anyone can check the license validity
• Restricted issuance of new licenses
• Disable issuing authority at anytime

Getting Started

Dependencies

• C++11 (C++14 if you are also building tests, since latest Google C++ Testing Library requires C++14)
• Crypto++ v5.6.5+ with Pem Pack
• cmake v2.8.12+
• Ripe

Installation

• Clone the repo

   git clone [email protected]:abumq/licensepp.git
  

• Install Crypto++

   wget https://raw.githubusercontent.com/abumq/abumq.github.io/master/downloads/cryptocpp.tar.gz
   tar xf cryptocpp.tar.gz
   cd cryptopp-CRYPTOPP_5_6_5
   wget https://raw.githubusercontent.com/abumq/abumq.github.io/master/downloads/pem_pack.zip
   unzip pem_pack.zip
   cmake .
   make
   sudo make install
  

• Install Ripe (if this fails, refer to full build instructions on the github)

    git clone [email protected]:abumq/ripe.git
    mkdir build
    cd build
    cmake ..
    make
    sudo make install
  

• Use CMake to build the project

  cd licensepp
  mkdir build
  cd build
  cmake ..
  make
  sudo make install
  
  ## build with test (make sure you have Google C++ Testing Library)
  cmake -Dtest=ON ..
  make
  sudo make install
  ./licensepp-unit-tests
  

• You can build cli tool to ensure license++ is installed properly

Integration

Once you have license++ properly installed please check out sample code for integration

Generate New Authority Key

Authority key is what is in key register (LICENSE_ISSUING_AUTHORITIES) You will need to generate a custom key for your software. This key is used to sign the digital license.

Authority key is essentially RSA keypair with : seperator. Format of this key can be defined as:

base64_encode(
 pem_format(
   rsa_private_key
 )
):base64_encode(
 pem_format(
   rsa_public_key
 )
)

You can use ripe command to generate new authority key or you can use openssl CLI tool to do so

ripe -g --rsa --length 2048 [--secret <secret>]

This will generate something like:

LS0tLS1CRUdJTiBSU0EgUFJJVkFURSBLRVktLS0tLQpNSUlFb2dJQkFBS0NBUUVBM0NGOENidXQyUlIvdXo4T3JmZ1VVNGtmTUdRZWtTNDQzbVVxQkFTeUpibjU3bmhPCllQbjA3N0hSaXZVNk9mYWp6YWFVRFVOZGFseDlFVmJ1YnYwNGQ0KzBHeTFMbDRPUXFITTg3eVRXSG81Z1JYbGcKNGlCeUFDRnVYMGVaNm1iSC9SWmFQcjZHT2ZrVTdJMVJ6V1dDUlYwc1IyN0N5Q1VkM0lScnduS2JSdzRUQkt0Tgpkakk5M3BncDZGWXN1UjFtU3FWSlVqWjhPY29EWTd1MHJUOStadEhMckQyeGh4YWE5N2RFOEtiMEJhbnlwMThaCmFORmY4M2pRbVZia0xra0F6c1RZczdyekRyVDNCbXN2SG1uTFlUTHBUSjM5SktLRmMvWXZBbjFQN3VWMDlXaG8KSTVPL2pyWXFoRmNEYTN0dkVCTkJPT3Z3aUhZZVZ2bjJuWW5QUXdJQkVRS0NBUUFNOHVrdHY3N3VwdHBXVHdEZApEcGZJcmJhS1lENElpaitVbklvQVBJTHpLUTZ6ckxsUS82VC9Dblc4NFQrcERvSWJKK3FYWGxES0JYREV5T0RaCldqQi9nT3g2RWJrbkI3MDNGZFpvYTVRZjZrSGwrQlRDQWVpV21JNEZtc3pSalpOTEgyNjRaWTlzMG1xa2dNaVQKbkk4eFFiZFBmdnhtSUUwTStMc0xjQ2RBYWlGZnBqdGtoK3d4Wm9UV29EMVQraXgyNGxQa3JBVHpiVXU4bDZwYgoyTW0xbGJnWE1icGIvaFdtcVR4TUFFcW9hVTNXS1lTb1RpQ2kwVHZNNXJ1aStya3cvRm5XMnpzTGFHYWhQWGlqClR5RVAzdXJDSGdIUG9EMG1hbWlIVnpmQUJFSFJVWURjZlNOOTJlQlRsZlVLUHBRYVI3SWY4TjVQNDVucXZLalAKRUNSUkFvR0JBTjlOSmdjSmVpR0xOS1daa3p2QTIvVkl2b1cwbEFuRmhROFRNb3BMYzdmQUtPZXZEMkwyclpXSQpjUFhuWjR4Q2ZLaDlYbmtISklST3dsVmxpVmd1cjBrQkFtbkZiVU4vZFJXR0hGVnJpTlgvVnNXZDRib3oyeEpOClhSRXNIenZUdmh0bnVJZjFzNzViOFlBQ3d4ek9IcDgvR0hhZVJnRndjNmtUeEhhU0Jxd3hBb0dCQVB4ZGUxUy8Kc1cwTGxMSU9IdDVrcEgwYzN6RnVOaDVLQXV6S2R0cElabUdYdDZweTRPNTBpWlZlQ1UzOU9uS1VMeDd4UHRFMApmTERVMFlLWWV4WXM4MnVOQUhlcHZzUE5VUkRMT2RiYW44TlVEb3pLdmlRbkkyT1ppQ3paazJCYTN2cW5SbEdKCmtLWFhUTVQwbnFEdk5Qb1NOL1o3cHl2SjVUeXNya3BMY0xtekFvR0JBSjJmM3B1T09CZXRqcE1DL29TSUlzdEMKYUY1aFdYQlBNTDlZMkdHZXJBazhXUndER2V1QTh3QWtFNEJuRytxSlNPOW5qZnNVR2NiT0x0TGVRdFRWcU9nOAo4cVVEMUtnZHZBOHhmV2w1RlV2RFRFOUNSUHZvWG1kRnF4c3VOQ283SE1nTStycFRGWGRQOWNQRnR1Y29GWjJWCjh5YU4xeEFUSkhkWlAyTEJiaDh4QW9HQVorcEIxNW81LzdsNWRuNUk4aWx3NkRrUW0rSVdTTFVRUTJKdExMUm0KWkd1bCt1UUNSQkhlVEpBaDh1L014Y1NMMzVDRFJ4V2N3VWlTZ1JHY0dEQ2dkNVJwbXE5T2pOd1NValdRU1drVQptN2t6S3VvU0R1THdkRTVISVliRU5yd0Jka1RndUNtVjZlODl1b0xYNStvR3dWTEx2OWlRSVJibDY4NmlIcGVJCnhPOENnWUVBa21CWEV4dHZ0d3ZJOXhleEFpalVhS1dqalNiM2VnbS9rV3VXRjhVUmRxeTR4US80WVBYSTFuZUIKNlBlSjcrSkFIakJtNGlhTm9tMkptM3J2aVA3dStFMzlwNDhrSSszWlFpd2FzeTUyTmdkL3kxS3lJeFNTM2JFWApoZXdIQU1qbWh4YVh3R1c4TWJZbW4xSklsTWhzTmZIcUhHQ1lQNklYR3hzR0pqeXFJdmc9Ci0tLS0tRU5EIFJTQSBQUklWQVRFIEtFWS0tLS0tCg==

Which is base64-encoded keypair seperated with :

Generate New Signature Key

License++ signature key is what's used to sign the licensee's signature. This is to protect the information with AES-CBC-128. Signature key is defined in 128-bit array in key register (LICENSE_MANAGER_SIGNATURE_KEY)

You can use ripe to generate new key

ripe -g --aes --length 128

This will produce something like 82F36C25A912389ABFF8091C759303D2. You then seperate each hex to create C++ array, i.e,

0x82, 0xF3, 0x6C, 0x25, 0xA9, 0x12, 0x38, 0x9A, 0xBF, 0xF8, 0x09, 0x1C, 0x75, 0x93, 0x03, 0xD2

You can use this to generate a copy-pastable line

ripe -g --aes --length 128 | sed -E 's/(..)/0x\1, /g' | tr -d '\n' | sed 's/, $//'

which will produce desired output like:

0x82, 0xF3, 0x6C, 0x25, 0xA9, 0x12, 0x38, 0x9A, 0xBF, 0xF8, 0x09, 0x1C, 0x75, 0x93, 0x03, 0xD2

This will now go in to the key register.

CLI

CLI tool provide ability to generate new licenses and validate existing license. Each CLI tool's version is linked directly with your version of key register.

See dedicated README

Issue New License

./license-manager --issue --licensee john-citizen --period 3600 --authority sample-license-authority [--signature <signature>] [--additional-payload <some string>] 

Validate License

./license-manager --validate license.file [--signature <signature>]

The validate checks for the following things:

• The license was issued by authorised license issuing authority
• License has been tampered with
• The license is still valid
• In case of signed license, the signature is valid

License Format

Licenses generated using License++ are base64 encoded JSON. They look like as follows:

{
    "authority_signature":"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",
    "expiry_date":1528386596,
    "issue_date":1515426596,
    "issuing_authority":"sample-license-authority",
    "licensee":"john-citizen",
    "licensee_signature":"61663531383163626334303566613461363362343232316632663764393638383A35574F4F4C466B532F7A4F79376446364F6155776C673D3D0D0A0D0A",
    "additional_payload":"SomeTestData"
}

Format Explained

Item	Description
authority_signature	Signature of the authority which prevents alteration in the license
expiry_date	License expiry date epoch
issue_date	License issue date epoch
issuing_authority	ID of issuing authority as per key register
licensee	Name of the license holder
licensee_signature	If licensee signed this license this is encrypted against key provided in key register. All the licenses signed by licensee will be validated against it at validation time.
additional_payload	Any string to be embedded into the license

License

Copyright (c) 2018-present @abumq (Majid Q.)

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.