In the present paper a new combined cryptographic method called Modified UES Version-I has been introduced. Nath et al. have already developed several symmetric key methods. It combines three different methods namely, Generalized Modified Vernam Cipher method, Permutation method and Columnar Transposition method. Nath et al recently developed few efficient combined encryption methods such as TTJSA, DJMNA where they have used generalized MSA method, NJJSAA method and DJSA methods. Each of the methods can be applied independently to encrypt any message. Nath et. al showed that TTJSA and DJMNA is most suitable methods to encrypt password or any small message. The name of this method is Ultra Encryption Standard modified (UES) version-I since it is based on UES version-I developed by Roy et. al. In this method an encryption key pad in Vernam Cipher Method also the feedback has been used which is considered to make the encryption process stronger. Modified UES Version-I may be applied to encrypt data in any office, corporate sectors etc. The method is most suitable to encrypt any type of file such as text, audio, video, image and databases etc.

In the present paper a new cryptographic method called UES Version-III has been introduced. Nath et al recently developed few efficient encryption methods such as UES version-I, Modified UES-I, UES version-II, TTJSA, DJMNA Nath et. al showed that TTJSA and DJMNA is most suitable methods to encrypt password or any small message. The name of the present method is Ultra Encryption Standard Version-III. It is a Symmetric key Cryptosystem which includes multiple encryption, bit-wise randomization, new advanced bit-wise encryption technique with feedback. In this paper, the authors have performed encryption entirely at the bit-level to achieve greater strength of encryption. In the result section the authors have shown the spectral analysis of encrypted text as well as plain text. The spectral analysis shows that UES-III is free from standard cryptography attack such as brute force attack, known plain text attack and differential attack.