nCipher Security Advisory No. 12 – In some circumstances, Diffie-Hellman keys generated by an HSM may be less secure than previously thought. An attack which recovers a vulnerable private key is (for typical parameters), expensive but possible.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/44525/nCipher12.txt
Source: https://packetstormsecurity.com/files/44525/nCipher12.txt.html