US Patent 10404458 Multi-round key encapsulation process

In a general aspect, a random seed value is used in a key encapsulation process to generate multiple ciphertexts for a recipient. The key encapsulation process includes multiple encapsulation rounds and each encapsulation round generates a respective ciphertext based on the random seed value and an additional value. The additional value includes an index indicating the encapsulation round. A symmetric key is generated based on the random seed value, and an encrypted message is generated based on the symmetric key. The ciphertexts and the encrypted message are provided for the recipient for transmission between nodes in a communication system.