# Classic McEliece

- **Algorithm type**: key encapsulation mechanism
- **Main cryptographic assumption**: Niederreiter's dual version of McEliece's public key encryption using binary Goppa codes
- **Scheme authors**: Daniel J. Bernstein, Tung Chou, Tanja Lange, Ingo von Maurich, Rafael Misoczki, Ruben Niederhagen, Edoardo Persichetti, Christiane Peters, Peter Schwabe, Nicolas Sendrier, Jakub Szefer, Wen Wang
- **Authors' website**: https://classic.mceliece.org
- **Version**: SUPERCOP-20191221

## Implementation

- **Source of implementation**: SUPERCOP-20191221, "vec" and "avx" implementations
- **Implementation version**: https://github.com/PQClean/PQClean.git, master, 89d34613364deca88659f6c2dd38708279c6bd24
- **License**: Public domain
- **Constant-time**: Yes
- **Optimizations**: Portable C with AVX2, BMI1, POPCNT instructions (if available at run-time)

## Parameter sets

| Parameter set             | Security model | Claimed NIST security level | Public key size (bytes) | Secret key size (bytes) | Ciphertext size (bytes) | Shared secret size (bytes) |
| ------------------------- | -------------- | --------------------------- | ----------------------- | ----------------------- | ----------------------- | -------------------------- |
| Classic-McEliece-348864   | IND-CCA2       | 1                           | 261120                  | 6452                    | 128                     | 32                         |
| Classic-McEliece-348864f  | IND-CCA2       | 1                           | 261120                  | 6452                    | 128                     | 32                         |
| Classic-McEliece-460896   | IND-CCA2       | 3                           | 524160                  | 13568                   | 188                     | 32                         |
| Classic-McEliece-460896f  | IND-CCA2       | 3                           | 524160                  | 13568                   | 188                     | 32                         |
| Classic-McEliece-6688128  | IND-CCA2       | 5                           | 1044992                 | 13892                   | 240                     | 32                         |
| Classic-McEliece-6688128f | IND-CCA2       | 5                           | 1044992                 | 13892                   | 240                     | 32                         |
| Classic-McEliece-6960119  | IND-CCA2       | 5                           | 1047319                 | 13908                   | 226                     | 32                         |
| Classic-McEliece-6960119f | IND-CCA2       | 5                           | 1047319                 | 13908                   | 226                     | 32                         |
| Classic-McEliece-8192128  | IND-CCA2       | 5                           | 1357824                 | 14080                   | 240                     | 32                         |
| Classic-McEliece-8192128f | IND-CCA2       | 5                           | 1357824                 | 14080                   | 240                     | 32                         |