Definition
Encrypting a file using a cryptographic key.
How it Works
Files are encrypted using either a single key for both encryption and decryption or separate keys. Single key encryption is symmetric encryption and using two key distinct keys is asymmetric encryption.
Symmetric Cryptography
Symmetric encryption uses the same cryptographic key for both the encryption and decryption a file. Managing keys at scale sometimes uses asymmetric key exchange. Protocols such as RSA or Diffie-Hellman can be used to share the symmetric cryptographic key with the others.
Asymmetric Cryptography
Asymmetric encryption is typically accomplished using public and private key certificates based on the X.509 standard. Files are encrypted using the public key and decrypted using their private key. Asymmetric encryption is typically slower than symmetric encryption and not widely used for large file encryption, but is popular for key wrapping, key exchanges, and digital signatures.
Considerations
- Continuous monitoring must be carried out to ensure private keys are not compromised and the certificate authority (CA) is trusted.
- Transfer of private keys between multiple devices must be performed securely.
Implementation perspective
File Encryption should be treated as a technical defensive capability rather than a product checkbox. In practice, teams should define the protected scope, the conditions under which the technique acts, and the observable evidence that demonstrates the intended behavior. For this technique, likely engineering context includes File.
Use the technique to increase the effort, prerequisites, or constraints an adversary must overcome before exploitation or misuse succeeds.
Questions to ask
- Which component, configuration, credential, interface, or behavior is being hardened?
- What secure baseline or policy defines the intended state?
- How are exceptions approved, time-limited, and reviewed?
- How is the hardened state verified after deployment and significant change?
Evidence and validation
- Approved hardening standards and configuration baselines
- Automated configuration or integrity assessment results
- Exception records with owners, rationale, and expiration dates
- Test results demonstrating that the intended restriction is enforced
Common failure patterns
- A secure setting is documented but not enforced consistently across the environment.
- Hardening breaks required functions and is permanently weakened through undocumented exceptions.
- Teams measure deployment of a product rather than verification of the hardened condition.
This implementation perspective is original Bare Metal Cyber educational content. It does not replace the official D3FEND definition or establish that a specific product implements the technique.
Technique hierarchy
Top-level family
Parent techniques
Direct child techniques
None listed at this level.
Artifacts and ontology entities
These relationships describe how D3FEND connects a defensive technique to artifacts or other ontology entities. They describe graph semantics, not a product certification.
Explicit technique relationships
Show inferred artifact relationship paths (1)
ATT&CK Enterprise mitigation relationships
These links come from the D3FEND ontology’s ATT&CK mitigation mapping. They help users navigate between the knowledge bases and do not guarantee mitigation effectiveness.
Offensive-technique relationships
These relationships are generated from D3FEND graph paths and are explicitly experimental. They should be treated as hypotheses for defensive analysis—not as proof that the technique prevents, detects, or removes an offensive behavior.
ATT&CK Enterprise (99)
Showing the first 60 of 99 source-derived relationships. Open the official D3FEND technique for the current graph view.
ATT&CK for ICS (8)
Authoritative sources
- Open this technique on the official D3FEND website ↗
- Open the official ontology resources ↗
- File Encryption 101: Safeguarding Your Sensitive Data ↗Veritas · InternetArticleReference
- NIST Special Publication 800-111 - Guide to Storage Encryption Technologies for End User Devices ↗Karen Scarfone, Murugiah Souppaya, and Matt Sexton · GuidelineReference
- NIST ITL Bulletin August 2020 - Security Considerations for Exchanging Files Over the Internet ↗Karen Scarfone, Matt Scholl, and Murugiah Souppaya · GuidelineReference
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