Systems and methods are disclosed for secure messaging and content sharing. In one implementation, a processor receives a content item in a first format, the content item being associated with an intended recipient, converts the content item into a second format, provides the content item, as converted into the second format, to a device associated with the intended recipient, receives, from the device associated with the intended recipient, one or more inputs in relation to a segment of the content item, processes the one or more inputs to determine that an authentication action is being performed with respect to the segment of the content item, and based on a determination that the authentication action is being performed with respect to the segment of the content item, provides an instruction to present the segment of the content item at the device associated with the intended recipient.