Wouldn't people just mine the currency themselves and exchange it locally? As long as the currency's token is unique and scarce, people can use it to trade.
If the purpose is to allow Iranians to circumvent restrictions on international trade, then you encounter the problem of not many people wanting to swap their goods or dollars for crypto-rial. (If the purpose is to allow people to make payments within the Iranian banking system in accordance with Iranian law, the crypto layer is redundant)