I'm trying to apply HMAC-SHA256 for generate a key for an Rest API.
I'm doing something like this:
def generateTransactionHash(stringToHash) key = '123' data = 'stringToHash' digest = OpenSSL::Digest.new('sha256') hmac = OpenSSL::HMAC.digest(digest, key, data) puts hmac end The output of this is always this: (if I put '12345' as parameter or 'HUSYED815X', I do get the same)
ۯw/{o���p�T����:��a�h��E|q The API is not working because of this... Can some one help me with that?
According to the documentation OpenSSL::HMAC.digest
Returns the authentication code an instance represents as a binary string.
If you have a problem using that maybe you need a hex encoded form provided by OpenSSL::HMAC.hexdigest
Example
key = 'key' data = 'The quick brown fox jumps over the lazy dog' digest = OpenSSL::Digest.new('sha256') OpenSSL::HMAC.digest(digest, key, data) #=> "\xF7\xBC\x83\xF40S\x84$\xB12\x98\xE6\xAAo\xB1C\xEFMY\xA1IF\x17Y\x97G\x9D\xBC-\x1A<\xD8" OpenSSL::HMAC.hexdigest(digest, key, data) #=> "f7bc83f430538424b13298e6aa6fb143ef4d59a14946175997479dbc2d1a3cd8" 
digest = OpenSSL::Digest.new('sha256') in the lower comment: stackoverflow.com/a/42832500/4706812
OpenSSL::HMAC.hexdigest('sha256', key, data) since ruby 2.5 ruby-doc.org/stdlib-2.5.1/libdoc/openssl/rdoc/OpenSSL/…Try This:
hmac = OpenSSL::HMAC.hexdigest(OpenSSL::Digest.new('sha256'), key, data) 
def make_payment(user) @key= SecureRandom.hex(10) #puts @key @secret_key = @key puts " this is the public key #{@secret_key}" @access_key= generate_key puts " this is the access key #{@access_key}" @name= @user.name puts "#{@name}" @time= Time.now.in_time_zone("Nairobi") puts "This is the time request sent #{@time}" @server_key = SecureRandom.base64 puts "This is the server key #{@server_key}" @data = 'This request is being made from Learnida for users to make a payment' @digest = OpenSSL::Digest.new('sha256') uri = URI.parse("https://learnida.com") @hmac = OpenSSL::HMAC.hexdigest(OpenSSL::Digest.new('sha256'), @secret_key, @access_key) puts "This is the HMAC #{@hmac}" req = Net::HTTP::Get.new(uri) req['Authorization'] = "TM-HMAC-SHA256 key=#{@access_key} ts=#{@time} sign=#{@hmac}" res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |http| http.request(req) } @hmacdigest= OpenSSL::HMAC.digest(@digest, @server_key, @data) puts" This is the HMAC:SHA-256: #{@hmacdigest}" #puts res.body #=> "\xF7\xBC\x83\xF40S\x84$\xB12\x98\xE6\xAAo\xB1C\xEFMY\xA1IF\x17Y\x97G\x9D\xBC-\x1A<\xD8" @sslkey= OpenSSL::HMAC.hexdigest(@digest, @server_key, @data) puts @sslkey In my case (Ticketmatic) I had to create the HMAC like above and add an Authorization header to the request with the HMAC in it.
hmac = OpenSSL::HMAC.hexdigest(OpenSSL::Digest.new('sha256'), secret_key, access_key + name + time) req = Net::HTTP::Get.new(uri) req['Authorization'] = "TM-HMAC-SHA256 key=#{access_key} ts=#{time} sign=#{hmac}" res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |http| http.request(req) } You can find a full gist here
And a blogpost with more explantion here
digest: Returns the authentication code an instance represents as a binary string.hexdigestinstead, it has the same signature asdigestbut returns hex-encoded string (from the docs it looks like it's the same string but human readable)