 Most of the implementations of RSA will accept exponents generated using either method (if they use the private exponent "d" at all, rather than using the optimized decryption method based on the Chinese remainder theorem described below), but some standards like FIPS 186-4 may require that .Any "oversized" private exponents not meeting that criterion may always be reduced modulo "λ"("n") to obtain a smaller equivalent exponent.Since any common factors of and are present in the factorisation of = = , it is recommended that and have only very small common factors, if any besides the necessary 2.