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A technique that encrypts cryptographic keys using a dedicated wrapping algorithm and a key-encryption key for secure storage or transfer.
DESCRIPTION
Key wrapping protects keys at rest or in transit by encrypting them with a key-encryption key (KEK) using specialized algorithms such as the AES Key Wrap (RFC 3394). It enables envelope encryption patterns in cloud KMS solutions and supports integrity via authenticated variants. Standards like NIST SP 800-38F define methods and security considerations. Compared to key transport, wrapping emphasizes algorithmic protection of keys rather than creating them elsewhere for delivery. Proper key lifecycle, rotation, and access control are essential.
ALTERNATIVE DEFINITIONS
NIST SP 800-38F
This Recommendation specifies cryptographic modes of operation for the protection of the confidentiality of cryptographic keys: the Key Wrap (KW) mode, the Key Wrap with Padding (KWP) mode, and the Tweakable Block Cipher Key Wrap (TBC-KW) mode.
Defines formal modes specifically for protecting cryptographic keys with wrap algorithms.
IETF RFC 3394
This specification describes an algorithm for wrapping (encrypting) keys using the Advanced Encryption Standard (AES) key wrap algorithm.
Provides the canonical AES Key Wrap algorithm definition and behavior.
AWS KMS Documentation
Envelope encryption is a practice of encrypting data with a data key, and encrypting the data key with a master key that protects the data key.
Explains envelope encryption, a common use-case where key wrapping protects data keys with master keys.
RELATED TERMS
Envelope Key AES Key Wrap NIST SP 800-38F RFC 3394 Envelope Encryption AWS KMS Azure Key Vault Key Rotation CMK
COMPETING TERMS
Key Transport
KNOWLEDGE AREAS
Data Security Infrastructure Data Privacy & Compliance
TARGET AUDIENCE
Security Architect Cybersecurity Engineer Cloud Architect DevOps Engineer Software Developer Chief Information Security Officer
EXTERNAL SOURCES
- Wikipedia - Key wrap
- NIST - Key wrapping modes specification
- IETF - AES key wrap algorithm
- Microsoft Learn - Azure Key Vault key operations
- AWS - Envelope encryption in KMS
TOP QUESTIONS
Why use Key Wrapping instead of general-purpose encryption?
Wrapping algorithms are designed for securely protecting keys, ensuring integrity and determinism appropriate for key materials.
Category: Relevancy
What is a Key Encryption Key in Key Wrapping?
A KEK is the higher-level key used to encrypt other keys, often stored and managed in a KMS.
Category: Overview
What are common mistakes in Key Wrapping?
Using non-authenticated wrapping where integrity is needed, or mishandling KEK lifecycle and access controls.
Category: Mistakes
How does Key Wrapping fit with envelope encryption?
Keys are wrapped by a master key, enabling scalable data key usage without exposing plaintext keys broadly.
Category: Example
What standards govern Key Wrapping?
NIST SP 800-38F and IETF RFC 3394 define modes and algorithms for wrapping keys with AES.
Category: Overview
What are risks of improper Key Wrapping?
Key leakage, integrity compromise, and inability to rotate safely if KEK management is flawed.
Category: Risks
How do cloud KMS services handle Key Wrapping?
They provide APIs for wrap/unwrap operations, secure KEK storage, access policies, and auditing.
Category: Management
Is Key Wrapping the same as Key Transport?
No. Wrapping encrypts an existing key with a KEK; transport typically involves generating a key and delivering it securely.
Category: Misunderstanding
Where to start learning Key Wrapping?
Begin with NIST SP 800-38F and RFC 3394, then review cloud KMS documentation for practical implementation guidance.
Category: Example