Najlae Falah Hameed  Al Saffar, 
    Public Key Cryptosystem Based on Graph Theory,
    Journal of Engineering and Applied Sciences,
    Volume 14,Issue 1,
    2019,
    Pages 219-223,
    ISSN 1816-949x,
    jeasci.2019.219.223,
    (https://makhillpublications.co/view-article.php?doi=jeasci.2019.219.223)
    Abstract: This study presents a new type of public key cryptosystem, send and receive a secure a written
message using English letters frequencies and some properties of graph theory. Experiment results of this type
of public key cryptosystem increased the level confidence for exchanging messages.
    Keywords: exchanging;confidence;receive;trees;graph theory;Public key cryptosystem