XX = X2^2 ZZ = Z2^2 aZZ = a*ZZ t0 = X2+Z2 t1 = t0^2 t2 = t1-XX E = t2-ZZ t3 = XX-aZZ t4 = t3^2 t5 = E*ZZ t6 = b4*t5 X4 = t4-t6 t7 = XX+aZZ t8 = ZZ^2 t9 = b4*t8 t10 = E*t7 t11 = 2*t10 Z4 = t11+t9 A = X2*X3 B = Z2*Z3 C = X2*Z3 D = X3*Z2 t12 = a*B t13 = C+D t14 = A+t12 t15 = B^2 t16 = b4*t15 t17 = t13*t14 t18 = 2*t17 R = t18+t16 t19 = C-D S = t19^2 t20 = S*X1 X5 = R-t20 Z5 = S