Discrete cryptographic such as RSA, knapsack, and discrete logarithms are the oldest and best cryptographic techniques.They are worked during finite field.In this paper, an attempt to another branch of cryptography was introduced.
In this proposed method, the interpolation branch of mathematics is used for text cryptography.Proposed method was introduced to cipher the plaintext message as word by word.In lunch boxes encryption part, three steps are implemented for product cipher word.
First, each letter of the word transformed to decimal number, then to binary.Second, the binary codeword transformed to decimal.Third, the finally cipher word is represented as triple.
So it transformed to three numbers by descending the original number.A quadratic polynomial is constructed where the three numbers are represented in the coefficients of the polynomial.By choosing of three temp small independent values, three dependent values are calculated as the code word.
For decryption part, the special polynomial Apparel technique is used for recover the quadratic polynomial.The rest steps are deduced conversely with the encryption part procedure.