"are now secure" is correct and can be used in written English.
It is used to describe a current state or condition of something or someone being safe or protected. Example: "Thanks to our increased security measures, our systems are now secure from any potential cyber attacks."
Locations once considered borderline are now secure.
After decades of wrangling, the trail rights are now secure.
With the £47 thus realised, he chips away at his most pressing debts, lobbing £10 to the hotel management (the family are now secure until Tuesday morning) and sending £4 to a former landlord and his wife, one of a tribe of creditors packed into the cluttered margins of his life, to deter them from chasing him for unpaid rent.
Alistair Wardell, from administrators Grant Thornton, said: "Their jobs are now secure and the new owners are confident that the business will now grow with the aim of taking on further employees in the near future".
Your confidential files and folders are now secure in your portable encrypted vaults and you can travel safely without any data theft worries.
Many planes are now secured by ropes, which will be replaced with chains and locks.
And, as American officials have eagerly noted, some 260 of 403 districts — covering 65 percent of the population — are now secured primarily by Afghan forces or in transition to Afghan control.
More newly-qualified teachers are now securing permanent positions so cannot do supply work.
The companies are now securing funds from investors, including Chinese and Japanese.
When any of WhatsApp's billion-plus users sees a discreet lock icon with the words, "Messages you send to this chat and calls are now secured with end-to-end encryption," they have Signal to thank.
