In this section, we lay out some of the research directions which have been least explored and remain as white spaces in the code-based cryptographic research. Though this paper elaborates on both PQC and code-based cryptography, the future research directions confine only to code-based cryptography for two reasons (i) future research direction in PQC ultimately boils down to any one of the PQC schemes viz. code-based, lattice-based, etc and (ii) our current research directions centers around code-based cryptography.

The linear codes are many in number and various code-based cryptographic algorithms using these code variants have been proposed. However, these cryptosystems except the McEleice cryptosystem which uses binary Goppa codes have been reported to be broken, discouraging the use of other linear codes. Even The variants of the McEliece algorithm using the other different types of linear codes apart from binary Goppa codes are susceptible to attacks. This is because the static code used in the algorithm is known earlier and also it results in a known structure of the linear code which could be cryptanalysed easily. However, the study of linear codes and the relationships between them, as described above explicate that it is possible to transform one code to another utilizing some operations on codes viz. augmenting, puncturing, extending, … etc as mentioned in Section 4.2. The existing variants of code-based cryptographic algorithms, for example, the McEliece uses a single code (binary goppa) as the basis for the encryption algorithm. Since, it is possible to transform one linear code to another using the possible code transformation operations, the same could be exploited in the encryption. Thereby, the cryptographic algorithm can dynamically choose to use any type of linear code to perform the encryption operation. This dynamic code transformation may produce any other existing linear codes or a new code that fulfills the properties for linear codes viz. Gilbert Varshmov bound, Singleton bound, etc. – for example, from the alternant code one can transform to the Generalized Shrivastava code or a new code fulfilling the linear code bounds. This dynamic approach provides two-fold advantages viz. i) the cryptographic algorithm can dynamically choose to use a particular type of linear code randomly with every session or even in between sessions so that it becomes very difficult to break the cipher since the structure of the linear code keeps varying ii)renders the otherwise unsafe linear codes to provide for quantum attack resistance thereby augmenting the utility of the various types of linear codes available in code-based cryptographic algorithms.