Abstract: A method and an apparatus for public-key encrypted communication includes: encrypting, by a first device, random information according to a first public key to obtain a first ciphertext; encrypting, by the first device, plaintext information according to a second public key to obtain a second ciphertext, where the plaintext information is unencrypted data to be sent by the first device to a second device, the first public key is represented in a form of a polynomial, the first public key is obtained through calculation on a truncated polynomial ring according to system parameters, the second public key is represented in a form of a polynomial, the second public key is randomly selected on a truncated polynomial ring, and the random information is randomly selected on a truncated polynomial ring; and sending, by the first device, the first ciphertext and the second ciphertext to the second device.