This may seem trivial, but for someone who knows little about this lebvel of security and wanting to really get it right first time, I found it quite offputting ... whereas the suggested process should be confidence-building, no?


URL: https://multibit.org/blog/2013/07/24/how-to-check-signatures.html



Step 1 - SHA1 in action

The first step on the road to security is access to strong cryptography. We'll start by creating a simple one line text file:

$ echo "Hello world" > example.txt

The above has an expected SHA1 hash of 33ab5639bfd8e7b95eb1d8d0b87781d4ffea4d5d which we will now attempt to verify. Depending on your operating system you'll need to install a few applications in a particular order to establish a solid trust foundation. Windows - install FCIV

Microsoft's File Checksum Integrity Verifier (FCIV) is a command line tool that provides access to SHA1 checksums.

Once installed, you can test it out on your example file as follows

fciv.exe -sha1 example.txt


It was not clear to me precisely what the 'example.txt' file should contain. If I entered the supplied line into a DOS box it didn't seem to work (in terms of creating a text file). So I decided to create the text file myself.. Reading the line literally the text to include should be:

$ echo "Hello world" > example.txt

or maybe just: $ echo "Hello world"

or maybe just Hello world

?? Anyway, I tried loads of options and at no time could I get fciv.exe to generate the given key!! >8-(

Giving up after 30 mins I tried the quick brown fox test easily found in Wikipedia and it worked first time, so the software is working and it is something to do with the suggested text file.

Sorry if this seems pedantic but if even very simple things don't check out, then it does not help confidence.


  • Sorry, but I find it difficult to see what your question here is.
    – Murch
    Commented Oct 24, 2013 at 13:27

2 Answers 2


I also am having trouble getting the hashes to match on a Windows system (MultiBit, Bitcoin-Qt .zip and .exe). I am using Microsoft's "unsupported" tool that the "hash document" references. I suspect that I will have better results using Linux.

In response to your specific issue, the "$" at the beginning of the command is the actual prompt. This implies the command is being entered in a linux\UNIX "shell" (i.e. bash shell). If it were a windows system you would see something like "C:\User\Sam> echo "Hello world" > example.txt" The command still works in windows, but as you pointed out the output file is different. In Linux/UNIX the same command would yield a file with only: Hello world No punctuation, extra spaces or lines. Therefore, the hash would be different under linux vs windows following the same command-line input.


Running the same test on Windows 7, the FCIV program returned:

25e64db6d4d1d6116ffe0b317918c98f3624cbed example.txt

Perhaps this is the same value you found. The example.txt file is 16 bytes long and, in addition to the words, it contains two double-quote characters, a space, carriage-return and linefeed.

Trying the corresponding experiment under Linux, the 33ab... checksum was returned. There were a couple of differences in the text files between Windows in Linux: the double quotes and extra space were not in the file, and the line ending was a linefeed only. Using Notepad++, I was able to edit the Windows file to generate the same checksum by fixing the differences.

Bottom line, the writer should have tried his demonstration on all platforms before assuming the answer would be the same.

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