using the fact that tangents frm same point have same length we can say that CB = CE.
now,
perimeter of CBD = CB+CE+ED+AD+1
=> 8 = 2CB + ED+AD+1 ....(1)
since AED is right angle triangle so using pythagoras theorum,
1 + ED2 = AD2 ....(2)
since CBD is right angled triangle so using pythagoras theorum,
CB2 + (1+AD)2 = (CB+ED)2 ....(3)
you have 3 eqns. 3 unknowns which can be easily solved.