From: Reid Thompson <Reid.Thompson@...>
Date: 2012-04-28T02:51:26+09:00
Subject: Re: why does this return 255 bits instead of 256 (and general bit byte hex string array crypt mayhem :P)

On Sat, 2012-04-28 at 01:05 +0900, instance_variable ok wrote:
> So I am doing something that requires me to manipulate things on the bit
> level, and am having a bit of a headache with learning to use pack and
> unpack to accomplish my goal. I thought I came one step closer with
> this, but was disappointed to see it thinks the result is 255 bits since
> I think it should be 256. What gives?
> 
> hash = OpenSSL::Digest::SHA256.new
> test_hash_value = hash << "anything"
> puts test_hash_value.to_s.to_i(16).to_s(2).length
> 
> => 255
> 
> shouldn't it be 256? What is a better way to get the binary
> representation of my hash string? I also note that
> 
[12:58:04] rthompso@raker2>~ 
$ irb
irb(main):001:0> require 'openssl'
=> true
irb(main):002:0> require 'digest/sha2'
=> true
irb(main):003:0> hash = OpenSSL::Digest::SHA256.new
=> #<OpenSSL::Digest::SHA256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855>
irb(main):004:0> test_hash_value = hash << "anything"
=> #<OpenSSL::Digest::SHA256: ee0874170b7f6f32b8c2ac9573c428d35b575270a66b757c2c0185d2bd09718d>
irb(main):005:0> p test_hash_value
#<OpenSSL::Digest::SHA256: ee0874170b7f6f32b8c2ac9573c428d35b575270a66b757c2c0185d2bd09718d>
=> nil
irb(main):006:0> puts test_hash_value.to_s.to_i(16).to_s(2).length
256
=> nil
irb(main):007:0>