rehash

v. make superficial changes to old ideas or creations and present them as new; reuse something; go back over; hash over

n. old material that is somewhat revised and altered and used again

In computer science, a hash table, or a hash map, is a data structure that associates keys with values. The primary operation it supports efficiently is a lookup: given a key (e.g. a person's name), find the corresponding value (e.g. that person's telephone number). It works by transforming the key using a hash function into a hash, a number that is used as an index in an array to locate the desired location ("bucket") where the values should be.
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Noun
1. old material that is slightly reworked and used again; "merely a dull rehash of his first novel"
(hypernym) material
(derivation) retrograde, hash over
Verb
1. present or use over, with no or few changes
(hypernym) recycle, reprocess, reuse
2. go back over; "retrograde arguments"
(synonym) retrograde, hash over
(hypernym) recapitulate, recap

(v. t.)
To hash over again; to prepare or use again; as, to rehash old arguments.
  

(n.)
Something hashed over, or made up from old materials.
  

      hasher