# EPUBCheck RSC-004: File … is encrypted, its content will…

Source: https://epublab.com/epubcheck/rsc-004/ (updated 2026-11-03)

EPUBCheck RSC-004 is an info message: “File "…" is encrypted, its content will not be checked.” A file is encrypted (listed in META-INF/encryption.xml), so EPUBCheck cannot read it and skips its checks.

- Official message (EPUBCheck 5.4.0): File "%1$s" is encrypted, its content will not be checked.
- Default severity: Info

## Typical causes

- Books protected with DRM, where content files are encrypted with a method EPUBCheck cannot read.

## How to fix it

- Nothing to fix if the encryption is intended; validate the unencrypted source EPUB to check the content.

Message text and severity: EPUBCheck (W3C, BSD-3-Clause). Explanation: EPUBLab.