How to use Docker Content Trust(DCT)?
Step 1: Enabling DCT
Firstly you need to set up an environment variable at the top. which enables the DCT and then you can enable it by setting it’s value 1 as mentioned below.
The DOCKER_CONTENT_TRUST = 1 is used for setting up DCT . for enabling setting its value = 1 as mentioned below you can also disable it by setting up its value = 0.
export "DOCKER_CONTENT_TRUST=1
and make if you are trying to pull the image. so the image is not present in your system locally. otherwise it gives an error message.
Step 2: Creation and set up of DCT keys
The authentication process works on the basis of unique keys so in the second step firstly you need to generate it. Signing keys are the important part of the DCT firstly you need to generate and then if you want to you can attach it with some tags follows the process as mentioned below.
The following command is used for creating key:
"docker trust key generate <Your_key> " to create signing key pairs.
Step 3: Sign your Docker Image
Signing is an important process for Docker images and you need to be concern about its authenticity before you pushing them to a registry. And by you need add your key as a signer by following command mentioned below:
docker trust signer add --key <"Key">/ <repository>
A key pair is required in order to sign a Docker image. The images are signed to prove the authenticity and verify the Docker images.We can now sign our docker image by running this command.
if everything goes well then the a message of success comes on the console as showed in the image below
docker trust sign <name-of-image
Step 4: Push your images to Registry
now in this step you push your image to a Docker registry using docker hub after that you signed. Make sure the images you signed is pushed to the respective registry. furthermore if you want so you can sign a specific tag and push it up to the registry the key generated by you.
Alternatively, this command can be used to push an image after the keys have been imported.
docker image push <registry>/<image>
Step 5: Verify Signed Images
if you want to know that the DCT is working well so. we can verify the signed Docker Images. Verifying signed images is important for confirming the authenticity and trustworthiness of Docker images. if you verify the signed image so it lower the chances of unwanted outcomes.
We can use this command to confirm the our images is properly signed.
docker trust inspect --pretty <image-name>
by using this command you can also check the details like signer keys, details about ID’s and status about the specified image. It also display details about the entity who signed the image, so you can take surety about its origin.
it also shows Signing Status which Indicates whether the image has been successfully signed or not and if the image is properly signed so you can view it in console in readable format.
Additional Tips
- Self-Hosted Registries: you can also Set up your Notary server for signature management.
- other tools: if you want so you can also explores Cosign for better signing experience.
- Automation: you can add with DCT with CI/CD pipelines for automation and better process.
Conclusion
DCT is an effective method for verifying the authenticity of Docker images is provided by Docker. This security feature make containerization process more secure and reliable. and clients doesn’t need to worry about image security and as we now that the maintaining security best practices. because “prevention is better than cure” just like it if you want to provide more security to your image you must need to enable DCT in your Docker image. Docker images, Docker Content Trust is an essential tool for safeguarding containerized applications and significantly improves security.
How to Use Docker Content Trust to Verify Docker Container Images
The world of containerized applications is based on trust. You rely on Docker images to be exactly what they say they are: secure, reliable, robust, and built with the right elements. But just like you can not just blindly trust any random ingredient in your kitchen, similarly the Docker image needs a kind of verification so we don’t need to be concerned about security issues.
DCT is an essential feature for your Docker container security. It allows you to focus on building and deploying amazing applications, while it takes care of the critical tasks of ensuring security.