ST=$(date +%s)
EXP=$(date -d "+31536000 seconds" +%s)
ACL="*/*"
SALT="aMQeBvbD540UhF6p"
KEY="c82c7bca6f418d8295a2f2b98bd9f430"
HAMC=$(echo -n "st=${ST}~exp=${EXP}~acl=${ACL}~salt=${SALT}" | openssl dgst -sha256 -hmac "$(echo -n ${KEY} | xxd -r -p)" -hex | awk '{print $2}')
SMP="?hdnts=st=${ST}~exp=${EXP}~acl=${ACL}~hmac=${HAMC}"
echo ${SMP}