o Major security workaround: - When building or running with any version of OpenSSL earlier than 0.9.8s or 1.0.0f, disable SSLv3 support. These versions had a bug (CVE-2011-4576) in which their block cipher padding included uninitialized data, potentially leaking sensitive information to any peer with whom they made a SSLv3 connection. Tor does not use SSL v3 by default, but a hostile client or server could force an SSLv3 connection in order to gain information that they shouldn't have been able to get. The best solution here is to upgrade to OpenSSL 0.9.8s or 1.0.0f (or later). But when building or running with a non-upgraded OpenSSL, we should instead make sure that the bug can't happen by disabling SSLv3 entirely.