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Vol. 1 · Ed. 2026
CyberGlossary
Entry № 603

l-Diversity

What is l-Diversity?

l-DiversityAn extension of k-anonymity introduced by Machanavajjhala et al. that requires each equivalence class to contain at least l well-represented values for every sensitive attribute.


l-Diversity, proposed in 2007, addresses two weaknesses of k-anonymity: homogeneity attacks (where every record in an equivalence class shares the same sensitive value) and background-knowledge attacks. By ensuring l distinct, well-represented values for sensitive attributes within each class, an attacker cannot pin down the sensitive value even after narrowing a target to a single class. Variants include distinct l-diversity, entropy l-diversity, and recursive (c, l)-diversity, each balancing privacy strength and information loss. l-Diversity is often combined with k-anonymity and t-closeness in privacy-preserving releases and is supported by tools like ARX, sdcMicro, and Amnesia for health, census, and survey datasets.

Examples

  1. 01

    Ensuring each age/ZIP group of patients includes at least three distinct diagnoses before publication.

  2. 02

    Applying entropy l-diversity to a salary dataset so that no equivalence class is dominated by one income band.

Frequently asked questions

What is l-Diversity?

An extension of k-anonymity introduced by Machanavajjhala et al. that requires each equivalence class to contain at least l well-represented values for every sensitive attribute. It belongs to the Privacy & Data Protection category of cybersecurity.

What does l-Diversity mean?

An extension of k-anonymity introduced by Machanavajjhala et al. that requires each equivalence class to contain at least l well-represented values for every sensitive attribute.

How does l-Diversity work?

l-Diversity, proposed in 2007, addresses two weaknesses of k-anonymity: homogeneity attacks (where every record in an equivalence class shares the same sensitive value) and background-knowledge attacks. By ensuring l distinct, well-represented values for sensitive attributes within each class, an attacker cannot pin down the sensitive value even after narrowing a target to a single class. Variants include distinct l-diversity, entropy l-diversity, and recursive (c, l)-diversity, each balancing privacy strength and information loss. l-Diversity is often combined with k-anonymity and t-closeness in privacy-preserving releases and is supported by tools like ARX, sdcMicro, and Amnesia for health, census, and survey datasets.

How do you defend against l-Diversity?

Defences for l-Diversity typically combine technical controls and operational practices, as detailed in the full definition above.

What are other names for l-Diversity?

Common alternative names include: l-Diverse k-Anonymity.

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