title: split private key(k1) such that only any two keys are necessary to decrypt it?
body: <p>I encrypt data using public key(k1). I decrypt it using private key pk1
  Is it possible to split private key(pk1) into keys pk2, pk3, pk4 and pk5 in such a way that only any two keys are necessary to decrypt it?</p>
  
  <p>Thanks.</p>