Add DSA interfaces
Add DSA interfaces

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