Add authentication support to coreSNTP demo (#625)

Update the coreSNTP demo to showcase use of symmetric key algorithm of authentication scheme for securing SNTP communication between client and server.
The demo uses the AES-128-CMAC algorithm for the generating Message Authentication Code for the client on sending the SNTP time request to server as well as validating the server response received by verifying if the payload present authentication code can be generated. Use of an authentication mechanism in SNTP communication protects against server spoofing attacks as well as man-in-the-middle attacks of server response modification.

The demo uses corePKCS11 library for the AES-CMAC operations. Also, the demo adds functionality of generating random number, using corePKCS11, for sending as a parameter to the Sntp_SendTimeRequest API.

Note: For symmetric key based security mechanism to be protective against malicious, it is IMPORTANT to securely pre-share the symmetric key between client and server.

lexicon.txt

@@ -7,6 +7,7 @@ aclk
 acm
 adc
 adcclk
+addclientauthcode
 adden
 addfaketaskwaitingtoreceivefromqueue
 addfaketaskwaitingtosendtoqueue
@@ -151,6 +152,7 @@ bss
 btimer
 btn
 buf
+buffersize
 bufsize
 burtc
 burtcclkdiv
@@ -441,6 +443,7 @@ dap
 dat
 datashee
 datasheet
+datatracker
 dbe
 dcdc
 dclr
@@ -811,6 +814,7 @@ het
 hetbase
 hetport
 hetreg
+hexstring
 hfclk
 hfrco
 hfxo
@@ -1396,6 +1400,8 @@ passsed
 passwordsize
 pasv
 pathlen
+pauthcodesize
+pauthcontext
 payloadlength
 pb
 pbasetime
@@ -1445,6 +1451,7 @@ pclientcert
 pclk
 pclkb
 pclwipappsblockinggettxbuffer
+pcmackey
 pcmethod
 pcmyreply
 pcname
@@ -1511,6 +1518,7 @@ pfm
 pfr
 pfs
 pfswe
+pfunctionlist
 phostname
 php
 phy
@@ -1609,11 +1617,13 @@ preceivedcommand
 predivide
 prefen
 premain
+prequestbuffer
 prescale
 prescaled
 prescaler
 presense
 presigned
+presponsedata
 prev
 printc
 printf
@@ -1812,6 +1822,7 @@ ps
 psc
 pscheckvariable
 psel
+pserver
 pserverinfo
 psignature
 psl
@@ -2048,6 +2059,7 @@ resetart
 resetprg
 resoltion
 resp
+responsesize
 resubscribe
 resubscribes
 resync
@@ -2214,6 +2226,9 @@ sni
 snprintf
 sntp
 sntpclienttask
+sntperrorauthfailure
+sntpservernotauthenticated
+sntpsuccess
 sntptask
 soc
 sockaddr
@@ -2370,6 +2385,7 @@ tim
 timeguard
 timertest
 timertimer
+timeserver
 tls
 tmr
 tmrdemoone