Experimenting Integration of Custom ECDSA Algorithm in OpenSSL

OpenSSL is one of the most widely used cryptographic library for establishing secure communication using transport layer security (TLS) protocols. The crypto library of OpenSSL supports both symmetric (AES) and asymmetric (RSA, ECDSA) cryptographic algorithms. Nowadays the software based secure key storage implementations also use OpenSSL for their cryptographic operations. However, there is need to customize the crypto modules of OpenSSL for two reasons: i) to avoid the proven attacks on OpenSSL crypto implementations ii) integrate the custom crypto implementations in applications like blockchain. In general, there is no reference document for adding new algorithms into OpenSSL. Hence this article summarizes the mechanisms by which custom cryptographic implementations can be added into OpenSSL crypto library and also discusses the pros and cons of every mechanism.