DSF Cryptography by Rotating Left the Samples Binary Values

A novel method of digital speech file cryptography will be proposed. The method will apply speech encryption-decryption at the bit level. The binary values of the speech samples will be shifted left to a defined number of rotating left digits. The private key will determine the length of the set of the bits to be rotated will be selected, the starting bit from where to start rotating and the number of rotating digits. The speech sample value will be represented in binary using 64_bits binary representation. Because of the fractional decimal value of the speech sample, changing the LSBs of the binary value may not affect the speech sample, so the starting bit for selecting the bits to be rotated will be investigated, and this bit will be used in the encryption-decryption process to get a damaged encrypted speech file. The private key will contains the starting bit; the bits set length and the number of rotating left digits, conditional selections of the private key value will be provided based on analyzing the quality of the encrypted speech files. The encryption and decryption process of the proposed method will be implemented in one round using a simple rotate left operation. The proposed method will not need key generation process; the values included in the private key will be directly used to apply speech encryption-decryption. The proposed method will be implemented using various speech files, the obtained results will be analyzed using quality, speed and sensitivity analysis to prove the efficiency of the proposed method.