Abstract :
Data transmission can be done with various service lines, one of which is
Short Message Service (SMS). Data exchange through SMS services is still found
gaps in the security and data confidentiality. This study utilizes cryptography
using the Pythagorean algorithm to secure data on the SMS service. The use of
the Pythagorean algorithm is based on the Pythagorean formula which is in
mathematics. Based on the comparison test results manually and application
calculations obtained the same results between encryption and decryption, while
for the key test results obtained decryption results that are close to the message
before encryption there is only one key that is able to decrypt the process well,
namely keys that use index 8 .