https://github.com/keygen-sh/example-cpp-cryptographic-license-files
Example of verifying cryptographically signed and encrypted license files using C++, OpenSSL, Ed25519 and AES-256-GCM.
https://github.com/keygen-sh/example-cpp-cryptographic-license-files
aes-256 aes-256-gcm aes-gcm ed25519 license-files license-keys licensing openssl
Last synced: 3 months ago
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Example of verifying cryptographically signed and encrypted license files using C++, OpenSSL, Ed25519 and AES-256-GCM.
- Host: GitHub
- URL: https://github.com/keygen-sh/example-cpp-cryptographic-license-files
- Owner: keygen-sh
- License: mit
- Created: 2022-08-05T20:47:45.000Z (about 3 years ago)
- Default Branch: master
- Last Pushed: 2023-12-08T16:22:54.000Z (almost 2 years ago)
- Last Synced: 2025-06-30T00:38:29.101Z (3 months ago)
- Topics: aes-256, aes-256-gcm, aes-gcm, ed25519, license-files, license-keys, licensing, openssl
- Language: C
- Homepage: https://keygen.sh
- Size: 104 KB
- Stars: 11
- Watchers: 2
- Forks: 10
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Example C++ Cryptographic License Files
This is an example of how to verify and decrypt [cryptographic license files](https://keygen.sh/docs/api/cryptography/#cryptographic-lic)
in C++, using OpenSSL, Ed25519 verification and AES-256-GCM decryption.
This example implements the `aes-256-gcm+ed25519` algorithm.
## Running the example
First up, add an environment variable containing your public key:
```bash
# Your Keygen account's Ed25519 public key.
export KEYGEN_PUBLIC_KEY="e8601e48b69383ba520245fd07971e983d06d22c4257cfd82304601479cee788"
# A license key.
export KEYGEN_LICENSE_KEY="E1FBA2-5488D8-8AC81A-53157E-01939A-V3"
```
You can either run each line above within your terminal session before
starting the app, or you can add the above contents to your `~/.bashrc`
file and then run `source ~/.bashrc` after saving the file.
Next, on macOS, ensure OpenSSL v1.1.1 is installed. If needed, install
using `homebrew`:
```bash
brew install openssl@1.1.1
```
Then compile the source using `g++`:
```bash
g++ main.cpp -o bin.out \
-std=c++17 \
-lssl \
-lcrypto \
-I /usr/local/opt/openssl/include \
-L /usr/local/opt/openssl/lib \
-I include/**/*.c
```
Then run the script, passing in a path to a license file:
```bash
./bin.out /etc/keygen/license.lic
```
Alternatively, you can prefix the below command with env variables, e.g.:
```bash
KEYGEN_PUBLIC_KEY="e8601e48b69383ba520245fd07971e983d06d22c4257cfd82304601479cee788" \
KEYGEN_LICENSE_KEY="E1FBA2-5488D8-8AC81A-53157E-01939A-V3" \
./bin.out examples/license.lic
```
You should see output indicating that the license file is valid, with its
decrypted dataset:
```
[INFO] Importing...
[OK] License file successfully imported!
[INFO] Verifying...
[OK] License file successfully verified!
[INFO] Decrypting...
[OK] License file successfully decrypted!
[INFO] Parsing...
[OK] License successfully parsed!
name=C++ Example License
key=E1FBA2-5488D8-8AC81A-53157E-01939A-V3
status=ACTIVE
last_validated_at=null
expires_at=2025-01-01T00:00:00.000Z
created_at=2022-08-05T19:27:36.492Z
updated_at=2022-08-05T19:27:36.492Z
entitlements=[FEATURE_ENTITLEMENT_C,FEATURE_ENTITLEMENT_B,FEATURE_ENTITLEMENT_A]
product=3bf34475-dfb4-42d8-a763-a2c89507f16d
policy=5ba80f5e-c3a6-4f38-bc0b-bd12053cef66
user=2068992b-f98f-4efc-95fd-687dbd0c868c
```
If the license file fails to decrypt, ensure that you're providing the correct
license key via `KEYGEN_LICENSE_KEY`. License files are encrypted with their
license's key, so an incorrect license key will fail to decrypt.
## Questions?
Reach out at [support@keygen.sh](mailto:support@keygen.sh) if you have any
questions or concerns!