Multiple round hash benchmark (CoffeeScript/node.js)

hash-benchmark.coffee

#!/usr/bin/env coffee
#
# This simulates a common pattern for deriving encryption keys
# from passwords.  It's somewhat alarming how fast computers
# have become.  You may have to try round counts over 100k to
# get a useful measurement!
#
# To use:
#  coffee hash-benchmark.coffee <algo> <rounds>
#
# Algo name options are in the node.js crypto docs, try sha256.

crypto = require 'crypto'

[ coffee, prog, algo, rounds ] = process.argv

data = new Buffer("seed!")

before = new Date

for i in [rounds..1]
  hash = crypto.createHash(algo)
  hash.update(data)
  data = hash.digest()

after = new Date

console.log "Took #{after - before} milliseconds"
console.log "Final content: #{new Buffer(data).toString('hex')}"