How do you secure the encryption keys and avoid hard-coding them in servlets?

1 Use external configuration files

One way to avoid hard-coding encryption keys in servlets is to store them in external configuration files, such as properties, XML, or JSON files. These files can be loaded by the servlets using the ServletContext or the ClassLoader. You can also encrypt the configuration files themselves using tools like Jasypt or Apache Commons Configuration. However, you still need to protect the access and location of these files and ensure they are not checked into version control or exposed to the web.

2 Use environment variables or system properties

Another way to avoid hard-coding encryption keys in servlets is to use environment variables or system properties. These are variables that are set by the operating system or the application server and can be read by the servlets using the System.getenv() or System.getProperty() methods. You can also use tools like Spring Boot or Jakarta EE to inject these variables into your servlets using annotations or configuration classes. However, you still need to secure the environment variables or system properties and ensure they are not logged or leaked.

3 Use a secret manager or a key vault

A more secure and scalable way to avoid hard-coding encryption keys in servlets is to use a secret manager or a key vault. These are services that store and manage encryption keys and other secrets, such as passwords, tokens, or certificates. They provide features like encryption, access control, auditing, and rotation. You can use tools like AWS Secrets Manager, Azure Key Vault, or HashiCorp Vault to integrate with your servlets using APIs or SDKs. However, you still need to authenticate and authorize your servlets to access the secret manager or the key vault and ensure they are not compromised.

4 Use a key management service or a hardware security module

A more advanced and robust way to avoid hard-coding encryption keys in servlets is to use a key management service or a hardware security module. These are services or devices that generate, store, and manage encryption keys and perform cryptographic operations, such as encryption, decryption, signing, or verification. They provide features like high availability, performance, compliance, and tamper resistance. You can use tools like AWS Key Management Service, Azure Key Vault, or Google Cloud KMS to integrate with your servlets using APIs or SDKs. However, you still need to pay for the service or the device and ensure they are compatible with your servlets.

5 Use a hybrid approach

A hybrid approach is to use a combination of the above methods to avoid hard-coding encryption keys in servlets. For example, you can use a secret manager or a key vault to store the encryption keys and a key management service or a hardware security module to perform the encryption and decryption operations. This way, you can leverage the benefits of both methods and reduce the risks of both methods. However, you still need to consider the trade-offs between complexity, cost, and security.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?