In the field of cryptography, extensive research has been dedicated to formalizing and analysing security offered by various encryption schemes. A fundamental objective of any encryption scheme is to hide the original message from potential adversaries with access to the ciphertext. However, with the evolution of cryptography, the focus has expanded to scenarios where adversaries can obtain additional information beyond the ciphertext, including access to the secret key. Clearly, if the adversary has full access to the ciphertext and the secret key, then it learns the underlying message.

This talk aims to explore “Incompressible Encryption”, a concept formalized by Guan et al. recently. Apart from offering standard security, an incompressible encryption scheme is secure against adversaries who are provided with a compressed version of the ciphertext but have access to the complete secret key. The primary focus of this talk will be to motivate scenarios involving such adversaries, formalize the security definition, and discuss simple constructions for incompressible secret and public key cryptosystems.