The "Gospel of Judas" was mentioned in the writings of Irenaeus (110-180 A.D.), one of the most respected leaders of the early church. He was of the very next generation after the original apostles of Jesus Christ had all died. Polycarp, who was trained by the Apostle John, discipled Irenaeus; and Irenaeus wrote that this gospel of Judas was a fictional heresy created by someone out of a group of embittered heretics and rebels of God.
Tabloid has always existed, and that is what this "gospel" is. A copy has simply survived the centuries. Unfortunately, today's media will sensationalize it with controversial one-liner headings and cliches, just to entice people in order to gain readership. In time the truth of its ficticiousness will become common knowledge, and this gospel of Judas will find its perspective as simply another vain attempt to slander God's true church.
This document was discovered back in the early 1980's in Egypt. The reason it was not published for so long is because the owner of the document, an artifacts dealer in Egypt, held out to get the price he demanded (he wanted $3 million dollars, but it is rumored he only got $300K). He finally sold it to antiquity dealer Frieda Nussberger-Tchacos, who eventually published it.