If the U.S. president gets his way, the signature that guarantees all the country's currency could soon look a lot less like someone's earnest John Hancock, and a lot more like a doodle.

Barack Obama nominated his chief of staff, Jack Lew, to become America's next treasury secretary on Thursday.

In addition to a host of duties related to stickhandling the U.S. economy, one of the more high-profile roles of that position is to endorse U.S. currency with a stamped signature, ensuring the money will be backed by the U.S. government.

The words "This note is legal tender for all debts, public and private" is written, in capital letters, on all U.S. bills, of any denomination. That pledge is accompanied by the signature of the treasury secretary. Most U.S. bills currently in circulation are likely to have the signatures of one of two men: Either Henry (Hank) Paulson, who held the office under President George W. Bush, or Timothy Geithner, who has held the office since Obama took power in January 2009.

Canadian bills have a similar promise, with the words "This note is legal tender" emblazoned in both official languages down the side of all bills. That's accompanied by the signature of the governor of the Bank of Canada — a post currently occupied by Mark Carney.

'It looks like money bags on the run.'—Elaine Charal, handwriting expert

All of the aforementioned men has a fairly typical signature — each with a hint of uniqueness, but for the most part, legible.

That could be set to change if Obama's man gets the top job, because Lew has one of the more memorable signatures of any public figure, ever.

As the photo illustration above shows, it starts with a barely decipherable soft "J" before quickly devolving into an incomprehensible series of loops.

"The fact that it's illegible means on a deeper level, he's someone who doesn't want to show his true self," Toronto handwriting expert and graphologist Elaine Charal said in an interview.

Charal says she has analyzed the signatures of many prominent figures, including Obama himself ("the threading in his letters shows he's a chameleon able to adapt to any situation," she says), but says Lew's is among the more interesting signatures she has ever come across.

"It looks like money bags on the run," she says. "It's probably a trademark but it's protective," she says. "He's protecting himself."

Signature hints at secrecy

In and of itself, a public signature that looks more like the result of someone testing a pen before buying it than an august endorsement from Uncle Sam is certainly among the least of America's problems.

And the story is likely nothing more than a sideshow in the ongoing U.S. debate over how America will pay down its debts. But amid talk of raising the debt ceiling and possibly minting a $1-trillion coin, it's one of the more lighthearted distractions.

Ultimately, it's probably fairly unlikely that Lew's signature will make it on all legal U.S. tender as is, without some sort of coaching or alterations. Indeed, the Senate could make changing it a requirement of his confirmation.

Geithner himself was asked to do just that for his signature, changing it from a short line with large bulbous letters into a more conventional, and readable version. Lew himself made a joke about it at the news conference naming him at the White House on Thursday, saying of his predecessor: "We both share a common challenge with penmanship."

Obama even played along, saying he'd never noticed Lew's signature, but he joked he'd considered rescinding the offer once he saw it.  But he said he was convinced once Lew promised to work on "at least making one letter legible in order not to debase our currency."

Because, as Charal says, "Your signature is your public self."

Unless something changes, puzzled Americans could possibly be forgiven for thinking the greenbacks in their pocket might not be worth the paper they're printed on.