RSA with $\lambda(n)$ or $\varphi(n)$ The PKCS #1 v2.0 specifications suggest using $\lambda(n) = \mathrm{lcm}(p-1,q-1)$. What is the benefit of choosing $\lambda(n)$ over $\varphi(n) = (p-1)(q-1)$ in RSA key generation?
Choosing $\lambda(n)$ rather than $\varphi(n)$ may result in a smaller private exponent.