I did a double-take at it being Bitcoin fees, since you'd think they'd want some stablecoin (even if not USD) so as to avoid inheriting the volatility, but no, they want Bitcoin specifically:

>“Once the email arrives and Iran completes its assessment, vessels are given a few seconds to pay in Bitcoin, ensuring they can’t be traced or confiscated due to sanctions,” FT reported, citing Hosseini.

https://beincrypto.com/iran-bitcoin-toll-hormuz-strait-tanke...