#!/bin/sh
set -e -u

username="00001112"
realm="193.28.87.182"
password="123test"
method=INVITE
digestURI="sip:000999667@193.28.87.182"
nonce="3ef574f083cc65c645ca929b21c7df5ebcc0"
nonceCount=
clientNonce=
qop=


# HA1=MD5(username:realm:password)
# HA2=MD5(method:digestURI)
# response=MD5(HA1:nonce:HA2)
# response=MD5(HA1:nonce:nonceCount:clientNonce:qop:HA2)    # when qop is given
DEBUG() {
    : "$@" >&2
}

MD5() {
    for arg; do DEBUG printf ' "%s"' "$arg"; done
    DEBUG echo
    printf "$@" | md5sum | cut -d' ' -f1 | tr -d '\n'
}

HA1=$(MD5 '%s:%s:%s' "$username" "$realm" "$password")
HA2=$(MD5 '%s:%s' "$method" "$digestURI")

if [ -z "$qop" ]; then
    MD5 "%s:%s:%s" "$HA1" "$nonce" "$HA2"
else
    MD5 "%s:%s:%s:%s:%s:%s" \
        "$HA1" "$nonce" "$nonceCount" "$clientNonce" "$qop" "$HA2"
fi
echo