Piazzi Smyth the astronomer-royal for Scotland wrote in his book The Great Pyramid (Reprint 1978) which shed some light on the origin of these heiroglyphs. On page seven Smyth quotes from the Athenĉum Newspaper May 21, 1870 p.677 :-

' In all the other chambers and passages, on the contrary, intended to be visited, and approached by admirably constructed white-stone passages, the masonry was finished off with the skill and polish almost of a jeweller ; and in them neither quarry marks nor "bat holes," nor painted marks, nor heiroglyphics of any sort or kind, are to be seen : excepting always those modern heiroglyphics which Dr. Lepsuis put up over the entrance into the Great Pyramid, " on a space five feet in breadth by four feet in height, " in praise of the then sovereign of Prussia ; and which have recently misled a learned Chinese envoy, by name Pin-ch'-un, into most absurdly claiming a connection between the Great Pyramid and the early monuments of his country.'

Dr. Lepsuis or Karl Lepsuis ( 1810 - 84 ), is well known today within Egyptological circles as a most formidable scholar and is widely held to be the greatest Egyptologist after Champollion, who by order of King Fredrick William IV of Prussia undertook an archeological survey of Egypt and Nubia in 1842.
It can only deduced from the evidence of the Athenĉum Newspaper that the eminent Egyptologist Dr. Lepsuis added heiroglyphic graffiti to the Great Pyramid as a complement to the King of Prussia, then left it up to others to be misled into thinking the heiroglyphics were original not fakes.
Can it then be within the realms of possibility that Vyse's discovery in 1837 of the heiroglyphic name of Khufu within the King's chamber roof spaces could also be a 19th century hoax or a score for one-upmanship. If this latter statement were found to be true then there would be absolutely no physical evidence within the Great Pyramid that it was built within the reign of king Khnum-Khufwy (Khufu).

Although information given by the Egyptologist W.M.F.Petrie in his book 'The Pyramids and Temples of Gizeh' adds a certain twist to the meaning of the King's Chamber heiroglyphs, if they were ever found to be genuine.
Petrie wrote that in most instances another name is found on the hidden stone blocks in the Great Pyramid and monuments at Giza and Wady Maghara, side by side with the name of Khufu. This other name in the majority of cases is Khumu-Khufu, which has the literal meaning of HE WHO IS UNITED WITH KHUFU.
From this, Petrie introduced a theory that named Khumu-Khufu as a co-regent of Khnum-Khufwy (Khufu). But from Khufu's curriculum vitae, he was not the type of man to share anything with anyone - except his daughter of course and that was for money.
It is from this evidence by Petrie that strengthens my acceptance of the hypothesis, that the original ancient name of the Great Pyramid was Khufu and that the fourth dynasty king Khnum-Khufwy after appointing himself as Re, then went on to usurp the then standing Great Pyramid on the Giza plateau for his own private necropolosis. This was how I believe he finally aquired the nickname of Khufu.    (See Khufu by Dr. Z. Hawass)