Crypto researchers have discovered a new, much faster, attack against the widely-used SHA-1 hashing algorithm. Xiaoyun Wang, one of the team of Chinese cryptographers that demonstrated earlier attacks against SHA-0 and SHA-1, along with Andrew Yao and Frances Yao, have discovered a way to produce a collision in SHA-1 over just 2^63 hash operations compared to 2^69 hash operations previously. A brute force attack should take 2^80 operations.
EDIT: oops. Fixed.