From SuspireWiki

Although Auspex is a potent Discipline, especially at high levels of mastery, a given Kindred’s execution of it is not always flawless. Other supernatural powers and abilities can cloud or contest the power of Auspex, the most common of these being Obfuscate — the direct opposite of Auspex, in many ways.

The heart of any Auspex-versus-Obfuscate contest is a mighty clash of wills, for both powers stem from and rely upon the power of the Kindred mind. When a character with Auspex uses his acute senses to see through another’s Obfuscate, make a contested roll of Wits + Investigation + Auspex versus Resolve + Stealth + Obfuscate. Whoever accumulates the most successes wins the battle of wills. Ties go to the defender. Most of the time, ties result in the Obfuscated character remaining hidden (as the Auspex-user is the initiator), but not always. In the event that a vampire uses Obfuscate right in front of a Kindred with Auspex, the hiding character is the challenger, as it is he who tries to hide in plain sight.