sha256-hash-file

sha256-hash-file tool

sha256-hash-file is a useful tool for getting an sha256 hash (fingerprint) from an input file using the standard crypto/sha256 package. I also added a flag to read in your .ssh/id_rsa.pub key to get your ssh sha256 fingerprint.

Table of Contents,

• OVERVIEW
• PREREQUISITES
• RUN
• TEST
• INSTALL
• USAGE
  • -h
  • -v
  • -ssh
  • -debug

Documentation and references,

• Refer to sha256-hash-from-file example in my-go-examples
• This repos github webpage built with concourse

OVERVIEW

In a nutshell, the guts of the code is,

plainTextBytes := []byte(plainText)

// HASH
sha256HashByte := sha256.Sum256(plainTextBytes)

// CONVERT TO STRING
sha256Hash := base64.RawStdEncoding.EncodeToString(sha256HashByte[:])

PREREQUISITES

I used the following language,

• go

You will need the following go packages,

go get -u -v github.com/sirupsen/logrus

RUN

The following steps are located in run.sh.

To run sha256-hash-file.go from the command line,

go run . testfile.txt
go run sha256-hash-file.go testfile.txt
go run sha256-hash-file.go -debug testfile.txt

If you run on testfile.txt your sha256 hash shall be,

r2pN5Sjq43jggvxvW34cT6s662//HfyemRss38ZA+vk

You may also use the -ssh flag to read in a public ssh key file,

go run . -ssh ~/.ssh/id_rsa.pub
go run sha256-hash-file.go -ssh ~/.ssh/id_rsa.pub
go run sha256-hash-file.go -ssh -debug ~/.ssh/id_rsa.pub

Its nice because you can check you have the right fingerprint at github.com/settings/keys.

You can also run the unix command to check your sha256,

 ssh-keygen -lf ~/.ssh/id_rsa.pub

TEST

The following steps are located in unit-tests.sh.

To create _test files,

gotests -w -all sha256-hash-file.go

To unit test the code,

go test -cover ./... | tee test/test_coverage.txt
cat test/test_coverage.txt

INSTALL

Will place an executable in your go bin,

go install sha256-hash-file.go

USAGE

sha256-hash-file {-h|-v|-debug|-ssh} [FILENAME]

-h

Help,

sha256-hash-file -h

-v

Version,

sha256-hash-file -v

-ssh

Check your public ssh file,

sha256-hash-file -ssh ~/.ssh/id_rsa.pub

-debug

sha256-hash-file -debug testfile.txt