A method for facilitating the integrity validation of data files includes providing a portable cryptographic device having a software verification key, and coupling the portable cryptographic device to a computing device. The electrical connector includes a comprising a first housing, a second housing removably fittable to the first housing, and a lock block disposed on the second housing and engageable with the first housing to secure the second housing at a predetermined position with the first housing. When the message record indicate that at least two addressees are working on a reply, a notice that multiple addressees are concurrently working on a reply is immediately sent to each of the addressees, creating a collaboration opportunities for the addressees. The annular inlet is divided into at least two axially offset inlet passages. It is proposed that additional webs be arranged lateral to the tilting web. Passive back-flushing prevents fouling of the heat exchanger due to sediments, scale, and mineral deposits which may be present in the circulating fluid.