Its not cryptography which is dead, but the notion of a keeping a key secret forever. Key compromise will happen with some regularity, but there are three thing

Its not cryptography which is dead, but the notion of a keeping a key secret forever. Key compromise will happen with some regularity, but there are three things you can do about it: 1. make key compromise harder, for instance require that an attacker compromise both your hardware and software to get your key, 2. limit the damage a key compromise can cause, for instance expire keys more often, randomly reissue keys, 3. and increase the speed with which you can recover from a key compromise. For example, the web PKI is completely compromised if a single CA key is compromised, but chrome can detect valid but forged google certs using key pinning and thereby alert the world. You can only use the stolen CA key to attack Google users once. The security community is advancing on all three fronts.