🔒 Encrypting Config Values With Jasypt

How the ENC(...) value in application.properties actually works.

Jasypt keeps a database password out of plain text in a Spring Boot project's application.properties — here's how it actually works.

What Jasypt does

A sensitive config value gets wrapped as ENC(encrypted-value), and the application decrypts it at startup using a specified algorithm (commonly PBEWITHHMACSHA512ANDAES_256) and a master password. The point is keeping a plaintext password out of a config file that gets committed to a repository.

Managing the master password is the crux of it

Decrypting the value requires the master password — and committing that password alongside the config file defeats the entire purpose of encrypting it. Keep the master password separate, via an environment variable (JASYPT_ENCRYPTOR_PASSWORD) or a dedicated secrets manager.

The limits of this approach

Jasypt encryption protects against a leaked repository or config file, but it's defeated if the master password itself leaks too (an exposed server environment variable, for instance). For stronger isolation, consider a dedicated secrets service like AWS Secrets Manager or HashiCorp Vault.

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