No, it is not true. It is a lie spread by anti-Jewish elements, with an angle to push, that the Jewish state is illegal. Although the Khazar literature claimed descent from Japeth, son of Noah, this claim seems only to have been a justification for their having converted, at least in part, to Judaism. Modern scholars generally consider them to be Turks who migrated from the East. Before their adoption of Judaism, they were, like other Turkish groups, shamanistic (their chief god was Tengri), but they had had some Confucian influence. Acc to Wikipedia: Jewish communities had existed in the Greek cities of the Black Sea coast since late classical times. Chersonesos, Sudak, Kerch and other Crimean cities possessed Jewish communities, as did Gorgippia, and Samkarsh / Tmutarakan was said to have had a Jewish majority as early as the 670s. The original Jewish settlers were joined by waves of immigration fleeing persecution in the Byzantine Empire, Sassanid Persia (particularly during the Mazdak revolts),[4] and later within the Islamic world. Jewish merchants such as the Radhanites regularly traded in Khazar territory, and may have wielded significant economic and political influence. Though their origins and history are somewhat unclear, the Mountain Jews also lived in or near Khazar territory and may have been allied with or subject to Khazar overlordship; it is conceivable that they too played a role in the conversion. At some point in the last decades of the 8th century or the early 9th century, the Khazar royalty and nobility converted to Judaism, and part of the general population followed.[5] The extent of the conversion is debated. Ibn al-Faqih reported in the 10th century that "all the Khazars are Jews." Notwithstanding this statement, some scholars believe that only the upper classes converted to Judaism; there is some support for this in contemporary Muslim texts.[6] However, recent archeological excavations have uncovered widespread shifts in burial practices. Around the mid 800s burials in Khazaria began to take on a decidedly Jewish flavor. Grave goods disappeared almost altogether. Judging by interment evidence, by 950 Judaism had become widespread among all classes of Khazar society. ====== After that, they considered themselves to be the protectors of Judaism, but were very tolerant of Christians living amongst them. Their kingdom survived for around 300 years before internal struggles and attacks from the Arabs destroy the khazar empire. DNA studies of the Ashkenazi jews shows some Khazar blood, as would be expected, Ashkenazi Y-Chromosome Jews originated in Middle Eastern populations, [12] as has the mitochondrial DNA (mtDNA) of at least 40% of the current Ashkenazi population.[13] So although Khazars might have been absorbed into the Jewish population it is unlikely that they formed a large percentage of the ancestors of modern Ashkenazim. In any case, over half of Israel is not Ashkenazi.

No, they come from the Ashkenazi people from Georgia in the Caucasus. http://en.wikipedia.org/wiki/Ashkenazi_Jews or http://iamthewitness.com/DarylBradfordSmith_Rothschild.htm