Tag-KEM/DEM是2005年提出的一种混合加密结构。Tag-KEM(Tag密钥封装机制)是其组成部分,采用公钥加密技术封装密钥。针对混合加密中不宜用慢的长消息公钥加密的问题,提出了一种用短消息公钥加密方案构造Tag-KEM方案的通用方法;结果证明了该方法在随机预言机模型下选择密文安全。该方法对Tag部分的处理不会带来额外的冗余,是第一个无需验证Tag部分有效方案,表明Tag-KEM/DEM结构优于KEM+DEM。 Tag-KEM / DEM is a hybrid encryption structure proposed in 2005. Tag-KEM (Tag Key Encapsulation Mechanism) is an integral part of this technology and uses public-key cryptography to encapsulate keys. Aiming at the problem that it is unsuitable to encrypt the long message public key in hybrid encryption, a general method of constructing Tag-KEM scheme by using the short message public key encryption scheme is proposed. The results show that the proposed method can select the ciphertext under the random oracle model Safety. This method does not bring extra redundancy to the processing of the Tag part. It is the first valid scheme that does not need to verify the Tag part, indicating that the Tag-KEM / DEM structure is superior to the KEM + DEM.