I would guess the I_C_{λ_1_i}_{λ_2_i} and (λ_1_i, λ_2_i) will be protected by some sort of security by obscurity, and coin reader manufacturers will only be given the info if they comply with some sort of security process and make it hard to extract the info from a coin reader. Probably just a way of making it harder to reverse engineer, not impossible.