What encryption types are illegal in the U.S.A
Effectively none.  Some ciphers are patented so you won't find them in OpenSSL.

In 1995 Bill Clinton signed an Executive Order 13026 that transferred control of encryption from the department in charge of munitions export to the commerce department.  Since then there has been a period of liberalization where now the only true restrictions are on exporting to countries under embargo.

You are free to write software that uses any key length to protect the messages.