The security of information and data can be done using cryptographic algorithms where the cryptographic security is carried out with special algorithms and requires keys that are known to the sender and receiver. this requires a key distribution process that is vulnerable to sniffing by third parties and this is most problem that occur in every cryptography problem. Three-Pass Protocol and Pohlig Hellman Algorithm are algorithms that can be used to overcome one of the key distribution problems that exist in cryptography for symmetric and asymmetric cryptography algorithms. The problem with security so far is the need for senders and receivers to know the key or password to open a message or data that is secured and this can be a problem if the key is stolen by an irresponsible party. Three-Pass Protocol communication with the Pohlig-Hellman algorithm allows senders and receivers to process encryption and decryption with the absence of a key distribution process by adding the use of the Sieve of Eratosthenes algorithm as a prime number generator in the Pohlig-Hellman algorithm, it will produce more secure ciphertext. The combination of Three-Pass Protocol, Pohlig-Hellman and Sieve of Eratosthenes produces good security in terms of ciphertext because the Pohlig Hellman algorithm has the same process as the RSA algorithm by using Private Key that only each sender and receiver knows, the combination of both testing this can minimize attacks from irresponsible third parties. PH and TPP are combined to make the communication highly secure. It makes use of SE and SSE as algorithm for PN generator which will be used for Encryption and Decryption in PH. The results of the combination of PH and TPP can produce a better ciphertext and because the sender and recipient of the message can use their respective keys. Similarly, under the PN length of 128bits, the required maximum key generation time is 192ms and total execution time is 195ms including the encryption time of 1.6ms and decryption time of 1.4ms. Under the PN length of 256bits, the required maximum key generation time is 264ms and total execution time is 268.2ms including the encryption time of 2.4ms and decryption time of 1.8ms.
