Kohi script is an undeciphered writing system used in Gandhara, in what is now Afghanistan and Pakistan, from the first to the eighth century AD.
This writing system bears some resemblance to both Brahmi script and Kharosthi script.
Kohi script from Gandhara, Discovery of Another Ancient Indian Writing System, by M. Nasim Khan, Gandharan Studies, vol. 1, pages 89–101 - which can be found here.
The Wikipedia page is