Research items
Current institution
University of Sumatera Utara | USU
Department of Computer Science
Current position
Master's Student
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University of Sumatera Utara
University of Sumatera Utara
University of Sumatera Utara
University of Sumatera Utara
University of Sumatera Utara
Following (49)View all
University of Sumatera Utara
Politeknik Negeri Medan
New York University
University of Sumatera Utara
University of Sumatera Utara
Research Items (4)
Modifications to Vigenere cipher are possible to make in order to be effective and efficient of this algorithm. In this study, we tried to modify Vigenere by exploiting RC6 key expansion to generate new keys used for encryption process, RC6 is a well-known as a modern cryptographic algorithm. If the RC6 Key expansion process will generate the S key as much as 2r+4, in this research will produce S Key as long as the plaintext length.Then for the encryption process done twice. The results show that the method proposed producing completely different key sequences (not repetitions like Vigenere cipher) can also produce an average avalanche effect of 17 bitsof the total 64 bits or about 26,56 %, better than the standard Vigenere which only reached 7.81%, but unfortunately no better than Vigenere with the RC6 key expansion without twice encryption process that reaches31.25% and of RC6-8/5/b with 35.94%.
A singer doesn't just recite the lyrics of a song, but also with the use of particular sound techniques to make it more beautiful. In the singing technique, more female have a diverse sound registers than male. There are so many registers of the human voice, but the voice registers used while singing, among others, Chest Voice, Head Voice, Falsetto, and Vocal fry. Research of speech recognition based on the female's voice registers in singing technique is built using Borland Delphi 7.0. Speech recognition process performed by the input recorded voice samples and also in real time. Voice input will result in weight energy values based on calculations using Hankel Transformation method and Macdonald Functions. The results showed that the accuracy of the system depends on the accuracy of sound engineering that trained and tested, and obtained an average percentage of the successful introduction of the voice registers record reached 48.75 percent, while the average percentage of the successful introduction of the voice registers in real time to reach 57 percent.
Vigenere Cipher is one of the classic cryptographic algorithms and included into symmetric key cryptography algorithm, where to encryption and decryption process use the same key. Vigenere Cipher has the disadvantage that if key length is not equal to the length of the plaintext, then the key will be repeated until equal to the plaintext length, it course allows cryptanalysts to make the process of cryptanalysis. And weaknesses of the symmetric key cryptographic algorithm is the safety of key distribution factor, if the key is known by others, then the function of cryptography itself become useless. Based on two such weaknesses, in this study, we modify the key on Vigenere Cipher, so when the key length smaller than the length of plaintext entered, the key will be generated by a process, so the next key character will be different from the previous key character. In This study also applied the technique of Three-pass protocol, a technique which message sender does not need to send the key, because each using its own key for the message encryption and decryption process, so the security of a message would be more difficult to solved.