Here's my solution in Ruby:
def crc32_crack(start_letter, end_letter, length, salt, hash) # Gets the crc32 code of the given length using the range from a start_letter...end_letter that matches the salt/hash
(start_letter..end_letter).to_a.repeated_permutation(length).each do |guess|
guess = guess.join
return guess if (crc32_check(guess + salt).to_i == hash.to_i)
end
end
def crc32_check(str, js_32_bit = true)
table = Zlib::crc_table.map {|el| el.to_s(16).upcase} # hex crc32 table
crc = 0
crc = crc ^ (-1)
max_32_int = (2**32)
str.length.times do |k|
a = (crc >> 8)
b = ("0x" + table[((crc ^ str[k].ord ) & 0x000000FF)]).to_i(16)
crc = (a ^ b)
if js_32_bit # See http://stackoverflow.com/questions/17056263/getting-the-same-result-from-ruby-as-javascript-for-bitwise-xor
if crc > (max_32_int/2)
crc = crc - max_32_int
elsif crc < -(max_32_int/2)
crc = crc + max_32_int
end
end
end
crc = crc ^ (-1)
crc = crc.abs
return crc
end
Runs very quickly!
crc32_crack('a', 'e', 4, "dFjO43n6", 1550194142)
=> "edde"