On Windows 7, QSslCipher::usedBits() and supportedBits() return values like 1 or 2 instead of 128, 256 etc. for the key length.

You can test it i.e. by using Qt example "Secure Socket Client" and connect to www.google.com on port 443. The expected value in the "Cryptographic cipher" label should be 128/128 bits, but instead 2/2 is returned. (Note that it is not actually necessary to connect to a host to check these functions.)

On Linux (Gentoo with the same libraries versions as on Windows) this error does not occur.