Extract text from CMS files
To convert your CMS file to another format, you need OpenSSL or other Encoded software.
To convert other file formats to the "Encrypted Data File" file type, you need software like OpenSSL or a similar tool.
The .CMS file extension primarily represents the Cryptographic Message Syntax format, a standard defined by IETF RFC 5652 (evolution of PKCS #7). These files are essential for securing email (S/MIME), digital signatures, and encrypted certificates. Because they are often stored in binary ASN.1 encoding, they are not human-readable and cannot be opened by standard text editors, creating a significant barrier for users who need to inspect the payload or certificate chain. To make these files usable, professionals typically use tools like OpenSSL to convert them into PEM (Base64 text) or P7B formats.
However, the .CMS extension suffers from significant file ambiguity. A large percentage of these files are actually cached images from WhatsApp (technically JPG or JFIF files masked with a .cms extension) or web assets encoded as WebP. Gamers also encounter them as asset bundles in titles like Car Mechanic Simulator or BeamNG.drive. This creates a confusing user experience where a file might be a high-security certificate or a simple cached photo. For crypto files, the best conversion target is PEM or TXT for analysis. For image artifacts, converting or renaming to JPG or PNG restores access.
Convert.Guru analyzes your CMS file, detects the exact format, and lets you read the text inside.
Users also converted CMF, PDF, CMS21B, AVIF, CERT, CSM, HTML, JPG, JPEG, WEBP, DOCX, CRL and CSV files.
The history of Convert.Guru began over 25 years ago in California with Tom Simondi’s file-format database. A former contributor to Space Shuttle development and a software pioneer of the 1980s, Simondi established a trusted resource for file type analysis that was even referenced by Microsoft Windows XP. Today, we use modern technology to process and convert thousands of file formats while continually improving our CMS converter.