Harare - Just what is a "latent image"? Or "alphanumeric lettering" for that matter?Less than a week after Zimbabwe introduced its controversial bond notes (and with reports they're already running out), the under-fire central bank has sent out an SMS to local phone numbers detailing the specific features of these notes.Thing is, it's incomprehensible.In a message sprinkled with random capitals and phrases that it's hard to believe anyone but a banknote security expert would understand, the RBZ's message reads: "Bond note security features: Optically variable ink, Tactile market, Latent image, See thru register, ZimBird watermark, Security thread, Alphanumeric lettering."Bond notes, a surrogate currency, were introduced on Monday in denominations of 2 US, to widespread wariness from locals worried that the bills may end up causing hyperinflation as Zimbabwe's bearer cheques did 10 years ago.This weekend's SMS campaign was likely prompted by fears that there are - or will soon be - fake bond notes circulating, given that the positioning of the security thread is not always the same. There are suggestions that two companies (or even countries) may be involved in the printing of the notes: Vice President Emmerson Mnangagwa has refused to say where they are being printed.Zimbabwe's privately-owned Standard newspaper on Sunday carried a quote from central bank deputy governor Khupukile Mlambo alleging that banks are "calling us requesting for more bond notes saying the ones they had had run out".The state-controlled Sunday Mail printed an editorial calling on the bank to release "expeditiously" the balance of the 75 million US it has promised to put into the system before the end of the year.But opposition MDC official Eddie Cross warns in his latest blog post that as US-dollar-strapped Zimbabwe banks increasingly start paying out clients in bond notes "all hell will break loose". Cross says that's because bank clients will only be able to recover a small part of the USD value the central bank insists that the new notes have.