Protection and document exchange
Share the document. Keep its classification context.
CryptIt in ClassifyIt 7.0 packages saved Office documents and Outlook attachments in the ClassifyIt Trusted Data Format: CI-TDF.
A container with a clear purpose
CI-TDF brings document content, classification and integrity information together in a ZIP container with a .tdf extension. Saved Word documents, Excel workbooks and PowerPoint presentations can be exported and imported again.
Encrypted payloads use OpenSSL-backed AES-256-GCM. Access uses local certificates or a shared PIN; the implemented workflows do not require a remote key service.
Project brief.docx.tdf
Document content
Structured classification
Integrity information
Illustrative CI-TDF structureChoose an appropriate export mode
| Mode | Protection | Access |
|---|---|---|
| None | Signed, classified container; payload is unencrypted. | No decryption secret required. |
| Generic | Encryption with an embedded preshared identity. | Any compatible ClassifyIt installation; not recipient-specific. |
| PIN | Password-based content protection. | Recipients with the PIN. Share it separately. |
| Certificate | Content encrypted for selected certificate recipients. | Matching private keys; the sender is included automatically. |
Outlook attachment encryption offers Generic, PIN and Certificate. Freeware exports signed, unencrypted containers regardless of the selected mode; supported decryption remains available.
Exchange public certificates with care
A signed, unencrypted .crt.tdf package carries the public certificate. The private key is not included. Own identities and imported public certificates are managed locally.
A valid enclosed signature does not alone prove a person’s identity. Use your organisation’s trusted exchange process to verify certificate ownership.
Understand the boundaries
- Optional document metadata remains clear text, including when the payload is encrypted.
- Root integrity uses a certificate signature or an HMAC depending on mode; PIN protection does not always establish an independently authenticated sender.
- CI-TDF is a specific ClassifyIt profile. Cross-vendor TDF interoperability must be tested.
- No claim is made for remote revocation after sharing or DRM.
- v7.0 cannot decrypt legacy .cit files. Recover them with a compatible older installation and original keys before re-exporting.
Bring your policy into Office
See what fits your team.
Discuss your markings, your Office environment and a practical evaluation.