Not sure what your implying, a function in mIRC that checks this or on the actual downloads page of the mIRC website..
Although both might have some credit i wouldnt see the point.
(sorry if you dont mean this one but..)
A function in mIRC that does this would be completely useless since it would serve no purpose and you would have nothing to compair the md5/sha to.
Also, having md5/sha on the mirc downloads page would also be useless since someone can download it from an external website that isnt required to put an 'md5/sha' string there.
Also one on the mirc site would be useless since you KNOW its the real thing, also if the md5s dont match when you complete the download mIRC is "small" enough to redownload it either from the same mirror or another one and its more than likely due to some download corrupt.
And finally, it would be completely useless to newbies since they more than likely dont know what md5/sha is, and its uses, and realistically people that know what they are, should know better.
Eamonn.