Catholicism vs Protestantism, is justification secured by faith, works or divine sacrifice?

I get mixed messages. Protestantism declares that justification is by faith alone. Catholicism declares that justification requires faith supplemented with various stipulations. **Yet both Protestants and Catholics seem to declare that what they really need are the shedding of divine blood.** Faith, works and divine blood... what part does each play in effectual justification for Catholics vs Protestantism?