OpenSSL Compatibility Layer Expansion

Recently, wolfSSL released version 4.0.0 of the wolfSSL embedded SSL/TLS library. This new version includes many new port/feature additions, maintenance updates, and a couple bug fixes. Among those new feature additions includes multiple new API added to wolfSSL's OpenSSL compatibility layer! The compatibility layer is a series of commonly used and essential API that users can utilize to transition from OpenSSL to wolfSSL. The function names are redefined as their wolfSSL counterparts, which have similar signatures and output to their OpenSSL counterparts.

The list of new compatibility API included with the most recent release include the following:

  • BN_Init
  • EVP_Digest
  • EVP_MD_CTX_block_size
  • EVP_MD_CTX_size
  • EVP_PKEY_assign_EC_KEY
  • EVP_PKEY_assign_RSA

The list of OpenSSL compatibility API that were added in the release prior can be found here:

wolfSSL also provides support for TLS 1.3! More information can be found here:

wolfSSL is available for download at the wolfSSL download page here (, or through a git-clone of the wolfSSL repository here (

For more information about wolfSSL or porting from OpenSSL, please contact