Caveat here that the crypto needs to actually be good, and key management and negotiation needs to be good, and key sizes and algo parameters need to be good, a

Caveat here that the crypto needs to actually be good, and key management and negotiation needs to be good, and key sizes and algo parameters need to be good, and that hardware needs to be good, and that key escrow systems ("Secure" Enclave, "Trusted" Platform Module) need to be good, you can not use computing services - everything must be done locally (the third party doctrine means that copies of this data must be kept to be made available), and the software stack must be kept secure and the hardware must be trusted.