Hybrid Key Encapsulation Mechanisms (KEMs), also known as KEM combiners, are constructions that combine multiple KEMs to derive a single shared secret while aiming to preserve specific security properties as long as a subset of the underlying KEMs is secure, while the rest of them are broken. Hybrid KEMs are particularly important in the transition to post-quantum cryptography, where combining classical and post-quantum mechanisms can help protect against potential weaknesses in either approach. However, achieving strong security guarantees depends on the combiner construction, the assumptions made about the underlying KEMs, and the security properties being considered. The goal of this project is to investigate existing hybrid KEM constructions and analyze their security guarantees and practical efficiency.

The student is expected to:

• Review the literature: Survey existing KEM combiners and hybrid KEM constructions, including their design principles.
• Analyze security properties: Identify and investigate the security properties achieved by different combiners, focusing on the assumptions required and the guarantees provided when one or more underlying KEMs are compromised.
• Compare existing methods: Evaluate and compare proposed constructions in terms of their security guarantees, computational efficiency, communication overhead, and practical applicability.
• Summarize findings: Identify the strengths and limitations of the existing approaches and discuss open challenges and potential directions for future research. The project should provide a clear understanding of the trade-offs involved in designing secure and efficient hybrid key establishment mechanisms.