Safeguarding cryptographic keys

Certain cryptographic keys, such as a number which makes it possible to compute the secret decoding exponent in an RSA public key cryptosystem, 1 , 5 or the system master key and certain other keys in a DES cryptosystem, 3 are so important that they present a dilemma. If too many copies are distributed one might go astray. If too few copies are made they might all be destroyed.