Public-key encryption in number theory is formalized through primitives defined by triples of algorithms (Key Generation, Encryption, Decryption) that satisfy Indistinguishability under Chosen Plaintext Attack (IND-CPA). The core theoretical mechanism utilizes Key Encapsulation Mechanisms (KEMs), which generate symmetric keys indistinguishable from random strings given ciphertexts alone, to construct asymmetric schemes via Hybrid Encryption. This approach reduces the complexity of building secure public-key systems by combining a lightweight KEM with high-speed symmetric encryption while maintaining rigorous mathematical guarantees against adaptive chosen-ciphertext attacks (IND-CCA).
Public-key encryption in number theory is formalized through primitives defined by triples of algorithms (Key Generation, Encryption, Decryption) that satisfy Indistinguishability under Chosen Plaint…