The fast growth of technology in schools needs safe systems for handling information,
especially for online transactions. The rise in data breaches shows that keeping personal and
transaction data safe is an important problem that needs serious attention. This research looks to
use the RSA cryptographic method to protect transaction data in the payment system of a
cooperative store at an Islamic boarding school. The system is created using a process called
Rapid Application Development, which has several steps like figuring out the problems,
gathering data, designing the system, putting it into action, and testing it out. The processes for
changing data into a secret code and then back to normal use RSA public and private keys,
where transaction data is first changed into ASCII codes. To check if everything works well and
that the RSA method does its calculations correctly, white-box testing is used. The results
indicate that transaction data can be safely encrypted before being saved in the database and can
be changed back to their original form without any changes. Thus, using the RSA method
significantly improves the safety and privacy of transaction data in the payment system at the
Islamic boarding school cooperative.
Keywords— RSA Algorithm, Islamic boarding school store, cryptography, encryption, data
security