Passphrase/password generator

new pass.zip

passgen.ps1

# passphrase/password generator
# Generates random passwords of at least 80-bit entropy using randomly-selected words
# selected using the system cryptographic RNG. More reason to trust than other methods because:
# - Verifiable good entropy source; your underlying system cryptographically secure RNG.
# - Verifiable level of entropy; instead of trying to be clever, which fails at a high rate, we mathematically calculate entropy.
# - Memorable, as it uses the most common English words
# - Does not give anybody else, like a website, an opportunity to record your passwords
if( -not (Test-Path .\randomwords.txt) ){
  echo "Downloading wordlist..."
  (New-Object System.Net.WebClient).DownloadFile("http://www.mieliestronk.com/corncob_lowercase.txt","$(pwd)\randomwords.txt")
}
$targetbits = 75 # how many bits of entropy, minimum, do you need?
#read wordlist
$rl = [System.IO.File]::ReadLines("$(pwd)\randomwords.txt")
#put into a set to ensure no duplicates
$hs = New-Object System.Collections.Generic.HashSet[String] ($rl)
#then convert to a list so we can index it
$lines = New-Object System.Collections.Generic.List[String] $hs
$numlines = $lines.Count
$bitsPerWord = ([math]::Log($numlines) / [math]::Log(2))
$wordsFloat = ($targetbits / $bitsPerWord)
$numWords = [math]::Ceiling($wordsFloat)
$totalbits = $numWords * $bitsPerWord
$rounded = [math]::Round($totalbits,2)
#Now get the random words
$out = ""
foreach($i in 1..$numWords){
  $randomBytes = new-object byte[] 4
  (new-object System.Security.Cryptography.RNGCryptoServiceProvider).GetBytes($randomBytes)
  $out += $lines[[BitConverter]::ToInt32($randomBytes, 0) % $numlines] + " "
}
echo "Your generated passphrase, with $rounded bits of entropy, is:"
echo ' '
echo $out
echo ' '
echo "A shorter, 96-bit-entropy password:"
echo ' '
$randomBytes = new-object byte[] 12
(new-object System.Security.Cryptography.RNGCryptoServiceProvider).GetBytes($randomBytes)
$shortpw=[System.Convert]::ToBase64String($randomBytes)
echo $shortpw
echo ' '

cmd /c pause