whiten

verb3

1. •
   (To cause) to become white or whiter; to bleach or blanch.

   • Age had whitened his hair.
   • The trees in spring whiten with blossoms.
2. •
   To normalize data so that the covariance matrix becomes the identity matrix; i.e., to remove correlations so each variable has unit variance.
3. •
   To increase the security of an iterated block cipher by steps that combine the data with portions of the key.