A creature with shroud cannot be the target of an equip ability. Shroud means it cannot be targeted by spells or abilities, and the equip ability targets.
A creature with shroud can, however, have an equipment attached to it. Either by having it equipped at a point when it didn't have shroud, or having it become attached through some method that doesn't target. For example, if you control a Cloak and Dagger and a Deft Duelist enters the battlefield, Cloak and Dagger's ability will trigger and on resolution you may attach it to the Deft Duelist.
Cloak and Dagger
|Tribal Artifact -- Rogue Equipment| Equipped creature gets +2/+0 and has shroud. / Whenever a Rogue creature enters the battlefield, you may attach Cloak and Dagger to it. / Equip 3
Deft Duelist
|Creature -- Human Rogue| 2/1 First strike / Shroud
