【高级技巧】备份加密：备份文件的加密保护封装

local KEY = nil
local function loadKey()
    if KEY == nil then
        KEY = fetchFromKeyService("backup_key_v" ..
            (tonumber(getsysvar("KeyVer")) or 1))
    end
    return KEY
end
local function encryptBackup(plainPath, encPath)
    local key = loadKey()
    local ok = cryptFile(plainPath, encPath, key)
    print("备份加密完成：" .. encPath)
    return ok
end
local function restoreDrill(encPath)
    local key = loadKey()
    local ok, rowCount = decryptAndVerify(encPath, key)
    print("恢复演练：" .. tostring(ok) .. "，校验行数 " .. tostring(rowCount))
    return ok
end

setontimerex(61, 86400000)
local function ontimerex61()
    restoreDrill("/backup/latest.enc")
end