The researchers said this allowed the attackers to focus on the highest value banknotes in order to minimise the amount of time they were exposed.
Despite these drains on Argentines' purchasing power, Ms Fernández has refused to allow a higher-value banknote.
No legal contracts are involved, and recipients are given only a code number or simple token, such as a low-value banknote torn in half, to prove that money is due.
Long queues wind around banks and ATMs in every city as people scramble to exchange their high-value banknotes.
In a surprise televised address on Tuesday night, Modi said the demonetisation of India's highest-value banknotes, worth about £6 and £12, would start from midnight.
The €500 note, worth around £389 at current rates, is one of the highest-value banknotes in the world, along with the Swiss 1,000 franc note (£707).
In Myanmar, the closest parallel to North Korea in the vicious incompetence of its thugocracy, the cancellation of high-value banknotes in 1988 contributed to a nationwide uprising.
Indian prime minister Narendra Modi's sudden ban on high-value banknotes will hit the war chests of his rivals before a key state election next year, sparking accusations that his strike against "black cash" will unfairly boost his party's chances.
Anglo American has said demand at its latest De Beers diamond sale showed a slowdown in response to India's withdrawal of high-value banknotes, but was still higher than a year ago when commodity trade was slumping.
In an effort to crack down on corruption, tax evasion and black markets, the prime minister, Narendra Modi, announced last month that the high-value banknotes, which account for roughly 80% of the total cash in circulation in India, were to be withdrawn.
With electronic payments increasing and the anonymity conferred by cash causing growing global concern, banks have also been keen to see the end of the €500 note, one of the highest-value banknotes in the world along with the 1,000 Swiss franc (£720) bill.
