A consortium of Japanese institutions used a cluster of 21 PCs (252 cores in total) to crack a 278 digit cryptographic key in just 148 days. This doesn’t mean that pairing-based cryptography, which is rapidly becoming a go-to standard in crypto, is now useless. (It’s to be used in everything from securing government networks to locking down financial systems.) Rather, the research is intended to establish just how long keys need to be in order to be reasonably secure against attacks by efficient algorithms and powerful computers.
From the press release:
Until now, cryptanalysis of pairing-based cryptography of this length was thought impossible as it was estimated to take several hundred thousand years to break. […]
As cryptanalytic techniques and computers become more advanced, cryptanalytic speed accelerates, and conversely, cryptographic security decreases. Therefore, it is important to evaluate how long the cryptographic technology can be securely used.