// Correctness for the case where the master pays
(pay=0) => P>=1 [ F (s1=1&s2=1&s3=1&s4=1) & func(mod,(agree1+agree2+agree3+agree4),2)=0 ]

// Correctness for the case where a cryptographer pays
(pay>0) => P>=1 [ F (s1=1&s2=1&s3=1&s4=1) & func(mod,(agree1+agree2+agree3+agree4),2)=1 ]