McEliece Cryptosystem

The McEliece cryptosystem is an asymmetric encryption algorithm developed in 1978 by Robert McEliece, the first such scheme to use randomization in the encryption process. It has never gained much acceptance in the cryptographic community but is considered a candidate for post-quantum cryptography because it is immune to attacks using Shor's algorithm, and it is based on the hardness of decoding a general linear code, using binary Goppa codes for its original private key so that the public key can be derived by disguising the selected code as a general linear code. Its main disadvantage is that its private and public keys are large matrices, with a standard parameter selection giving a public key 512 kilobits long, though its encryption and decryption are faster than RSA's.