For someone involved in top secret negotiations over the release of Societ dissident Anatoly Scharansky in exchange for spies held in the West, Chicago-born Aviva Rubin has a remarkable flare for personal publicity.

Until two days ago, Rubin was just one more anonymous guest staying at the modest Prinz Eugen hotel near Vienna's south station. She could have been mistaken for one of the thousands of travelers who pass every year through Vienna - one of Europe's great tourist centers and now a key transit point between East and West.

Then at noon Tuesday, the Vienna bureau of Reuters news agency circulated a story that Scharansky, sentenced last month to 13 years in prison and labor camp on treason charges, was about to be freed in an intricate spy swap. Within half an hour, the phone in Rubin's seventh floor room began ringing. It's been ringing ever since.

Downstairs in the lobby, reporters from Austrian television began setting up lights. Rubin's two Russian-born companions transformed themselves into bodyguards and kept an eye out for intruders. The hotel manager promised her two free days to see "beautiful Vienna when it's all over" at his expense. And 48-year-old Rubin put on one of her two specially packed wigs.

By a kind of osmosis incomprehensible to anybody not in the news business, the name of Rubin - varously high school teacher, travel agent, and mother of four - had become inseparably linked in the minds of foreign editors of the world's major newspapers with that of Anatoly Scharansky - human rights activist, computer scientist, and alleged CIA agent.

The connection is provided by an Israeli millionaire who is rapidly emerging as a key, and also publicity-conscious, entrepreneur, in the murky business of East-West spy swaps. His name: Samuel Flatto-Sharon, also 48 and now an independent member of Parliament in Israel to which he fled from France after being sentenced to a five-year jail term on charges of fraud.

As Flatto-Sharon's personal secretary, Rubin ("I do all the cloak-and-dagger work") has spent the last month waiting for telephone calls from her boss in various parts of Europe. Two weeks ago, she was a Moscow where she contacted Scharansky's family.

Rubin describes Flatto-Sharon as "charming, wealthy, and sophisticated." She attributes his role in the present bargaining - which envisages the release of three Communist spies being held in the United States and West Germany - to the greater entrepreneur in comparison with government officials.

"The Russians accept him because he has proved he can deliver the goods," she said, referring to Flatto-Sharon's part in the swap last April involving American college student Alan Van Norman, arrested in East Germany after attempting to smuggle a family out of the country; Israeli Muron Marcus imprisoned in Mozambique after his private plane blew off course, and American Air Force clerk Robert Thompson who was jailed as a Soviet spy in 1965.

Also involved in the present negotiations on the Communist side are two veterans of sensitive East-West deals: The East German lawyer Wolfgang Vogel and the Soviet journalist Victor Louis. They too have the reputation of being charming, wealthy, and sophisticated.

In Vladimir prison, 100 miles east of Moscow, a young Soviet Jew is waiting to be flown to Israel - probably via a neutral Western European city. And in room 708 of Vienna's Prinz Eugen Hotel, a middle-aged American Jew is waiting for the phone to ring.

But just what else she is doing there, nobody seems to know.