Today we discuss a specific automation issue. This pertains to authentication:

We explain a difference between a JWT digest token and an HMAC hash:

We construct a JWT token this way:

    def data_to_sign(endpoint, environment, owner):

        banner = '{"alg":"SHA256withRSA","kid":"' + environment + '"}'

        banner = base64.b64encode(banner)

        start = int(datetime.datetime.now().strftime("%s"))*1000

        end = datetime.datetime.now() + datetime.timedelta(seconds=300)

        end = int(end.strftime("%s"))*1000

        expiration = '{"iss":"' + environment + '","nbf":' + str(start)  + ',"sub":"' + owner  + '","exp":' + str(end) + ',"aud":"' + endpoint + '"}'

        expiration = base64.b64encode(expiration)

        data_to_sign = banner + "." + expiration

        return data_to_sign

    def signature(endpoint, environment):

        data = data_to_sign(endpoint, environment)

        unpacked = data.split('.')

        unpacked[0] = base64.b64decode(unpacked[0])

        unpacked[1] = base64.b64decode(unpacked[1])

        unpacked = unpacked[0]+"."+unpacked[1]

        with open('./pem/file.txt', 'w') as f:

             f.write(unpacked)

        cmd = 'openssl  dgst -sha256 -sign ./pem/privateKey.key  -out ./pem/signature.sign ./pem/file.txt'

        cmd_execute(cmd.split())

        digest = ''

        with open('./pem/signature.sign', 'rb') as f:

             digest = base64.b64encode(f.read())

        cmd = 'openssl  dgst -sha256 -verify ./pem/privateKey.pub  -signature ./pem/signature.sign ./pem/file.txt'

        output = self.cmd_execute(cmd.split())

        # output says 'Verified'

        auth = data_to_sign + "." + digest

        return auth

       PyJwt encapsulates something similar with the following syntax:
       import jwt

       jwt.encode({'some': 'payload'}, 'secret', algorithm='HS256')

       The auth goes in the Authentication header field of the https request

We construct an HMAC token this way:
        def auth(KeyId, timestamp, token, SomeSecret):

                HMAC_KEY =  SomeSecret.decode('hex')

                CanonicalizedResource = 'timestamp=' + timestamp + '&' + 'token=' + str(token)

                StringToSign = CanonicalizedResource

                Signature = base64.b64encode(

               hmac.new(

                    HMAC_KEY,

                    StringToSign,

                    hashlib.sha256

                    ).digest()

                )

                auth = KeyId + ":" + Signature

                return auth

#codingexercise
Find the longest consecutive subsequence in a sequence

Use a hash table and add all elements in the sequence.

For every element check if it is a start of subsequence, previous one does not occur.

Count the length from each subsequence.

Return the max of the counts.

int GetLMS(List<int> digits)
{
var h = new Hashtable<int>();
for (int i = 0; i < digits.count; i++)
   if h.Contains(digits[i])
      h[digits[i]]++;
   else
      h[digits[i]] = 1;
int max = 0;
for (int i = 0; i < digits.count; i++)
{
  if (h.Contains(digits[i]-1) == false)
  {
      int count = 0;
      for (int j = digits[i]; h.contains(j); j++)
            count++;
      if (count > max)
          max = count;      
   }
}
return max;
}

Trivia question:

The question is why does net ads join fail with  ads_sasl_spnego_gensec_bind ? Hint: is this a kerberos failure.