A Practical Approach for Secured Data Transmission using Wavelet based Steganography and Cryptography

Steganography and cryptography methods are used together with wavelets to increase the security of the data while transmitting through networks. In the discrete wavelet transform, an image signal can be analyzed by passing it through an analysis filter bank. This analysis filter bank consists of a low pass and a high pass filter at each decomposition stage. Another technology, the digital watermarking is the process of embedding information into a digital (image) signal which may be used to verify its authenticity or the identity of its owners. The watermark to be embedded is 'text'. Before embedding the plain text into the image, the plain text is encrypted by using Data Encryption Standard (DES) algorithm. The plain text can be any sentence in English, and the key can be anything in English with a length of 8-characters. The encrypted text is embedded into the LL subband of the wavelet decomposed image using Least Significant Bit (LSB) method. Then the inverse wavelet transform is applied and the resultant image is transmitted to the receiver. At the receiver's end, the image is transformed using wavelet, from the LL subband the encrypted text is extracted by using the LSB method and the result is decrypted using DES.