--[[
S: realm="elwood.innosoft.com",nonce="OA6MG9tEQGm2hh",\
   qop="auth",algorithm=md5-sess,charset=utf-8
C: charset=utf-8,username="chris",realm="elwood.innosoft.com",\
   nonce="OA6MG9tEQGm2hh",nc=00000001,cnonce="OA6MHXh6VqTrRk",\
   digest-uri="imap/elwood.innosoft.com",\
   response=d388dad90d4bbd760a152321f2143af7,qop=auth
S: rspauth=ea40f60335c427b5527b84dbabcdfffd
]]--

local username = "chris"
local password = "secret"
local realm = "elwood.innosoft.com"
local nonce = "OA6MG9tEQGm2hh"
local cnonce = "OA6MHXh6VqTrRk"
local uri = "imap/elwood.innosoft.com"
local response = "d388dad90d4bbd760a152321f2143af7"


local en1 = crypto.digest.new("MD5", nonce)
local en2 = crypto.digest.new("MD5", cnonce)

local md5 = en1:final(("%s:%s:%s"):format(username, realm, password))
local ha1 = en1:final(("%s:%s:%s"):format(md5, nonce, cnonce))
local ha2 = en1:final(uri)

local dec = en2:final(("%s:%s:00000001:%s:auth:%s"):format(ha1, nonce, cnonce, ha2))
print(dec) --> 6b13686de7dc2819a021f2f41a470319
print(dec == response) --> false