Thanks @alastairstevenson,
I did try with Web Digest before posting for help here. One suggestion was:
HA1 = MD5(username:realm: password)
HA2 = MD5(method:digestURI)
response = MD5(HA1:nonce:HA2)
For this method, I know how to get HA1 but have no idea of how to calculate HA2. For http request...