App Store Rejection for using libcrypto.dylib

Nope. It’s just the cryptographic lib used by it.

" The OpenSSL crypto library implements a wide range of cryptographic algorithms used in various Internet standards. … libcrypto consists of a number of sub-libraries that implement the individual algorithms."

https://www.openssl.org/docs/man1.0.2/man3/crypto.html

OpenSSL depends on it.