Why are you posting such outrageous nonsense and lies?
Iran is using the Perso-ARABIC alphabet which is an exact copy of the Arabic alphabet expect four additional letters.
I cannot post any links yet but search on "Persian alphabet".
The Arabic alphabet has nothing to do with some Avestan alphabet. In fact all your Iranian alphabets are copies of various Semitic alphabets, especially the Phoenician alphabet which even your own links confirm and which is the ancestor of the Arabic alphabet as well and almost every alphabet of the world too.
Search on "Phoenician alphabet".
The Phoenician alphabet in return derives from the Egyptian hieroglyphs which is the oldest script on the planet.
Search on "Egyptian hieroglyphs".
No Sassanians ruled any part of Arabia outside of tiny areas. On the other hand Arabs ruled entire Iran for centuries.
Arabic alpahbet descends from the Semitic Nabatean alphabet which in returns descends from the Semitic Syriac, Aramaic, Phoenician, Proto-Sinaitic and lastly Egyptian alphabets.
Search on "Arabic alphabet".
So you are very wrong with your empty claims.
Writing was also invented in the Arab world. It's ridiculous to see an Iranian belittle much older cultures in the Arab world. Laughable really.