use mgf1_hash_supported to simplify some logic
use mgf1_hash_supported to simplify some logic

kimvais/cryptography,Hasimir/cryptography,kimvais/cryptography,Ayrx/cryptography,kimvais/cryptography,Lukasa/cryptography,Hasimir/cryptography,bwhmather/cryptography,Ayrx/cryptography,Lukasa/cryptography,dstufft/cryptography,kimvais/cryptography,Hasimir/cryptography,sholsapp/cryptography,dstufft/cryptography,dstufft/cryptography,Lukasa/cryptography,skeuomorf/cryptography,skeuomorf/cryptography,Ayrx/cryptography,bwhmather/cryptography,sholsapp/cryptography,bwhmather/cryptography,skeuomorf/cryptography,Ayrx/cryptography,Hasimir/cryptography,dstufft/cryptography,sholsapp/cryptography,dstufft/cryptography,sholsapp/cryptography,bwhmather/cryptography,skeuomorf/cryptography