In a post on Wednesday, researchers Alex Halderman and Nadia Heninger presented compelling research suggesting that the NSA has developed the capability to decrypt a large number of HTTPS, SSH, and VPN connections using an attack on common implementations of the Diffie-Hellman key exchange algorithm with 1024-bit primes. Earlier in the year, they were part of a research group that published a study of the Logjam attack, which leveraged overlooked and outdated code to enforce “export-grade” (downgraded, 512-bit) parameters for Diffie-Hellman. By performing a cost analysis of the algorithm with stronger 1024-bit parameters and comparing that with what we know of the NSA “ black budget ” (and reading between the lines of several leaked documents about NSA interception capabilities) they concluded that it’s likely NSA has been breaking 1024-bit Diffie-Hellman for some time now. Read more…

Taken from:
How to Protect Yourself from the NSA If You Use 1024-bit DH Encryption