الفهرس 
Chapter1 : IntroductionOnly 14 pages are availabe for public view
 |  | from | 153 |  |  |
| | | from | 153 | | |
Abstract
The handwritten signature is an important technique for both authentication and authorization for applying security rules to documents in government offices that require the employee’s signature. Cryptography and steganography are regarded as the most essential data hiding techniques for a reliable safety system. We combine steganography and cryptography techniques for hiding the sensitive data in the carrier covers and hiding the content of the secret message.
The first proposed technique is a hybrid data hiding and encryption technique that is implemented in the spatial domain. The secret handwritten signature image is first encrypted using the public key algorithm (RSA), then randomly inserted to be hidden in one of the last three bits of that pixel based on a mathematical randomized formula over all pixels of the carrier media (image). The proposed technique is implemented on grayscale and color cover images. It achieved enhanced data hiding results in terms of performance, protection, and imperceptibility properties and the histogram of the proposed technique is better and provides more protection than the ordinary sequential Least Significant Bit (LSB).
For the second proposed technique, a methodology for securing hidden handwritten signatures has been developed by combining cryptography and steganography approaches. This approach offers multi-level security by combining the Blowfish method for encryption with modified-LSB steganography to hide the resulting cipher in a cover picture.
After encrypting the handwritten signature, every 2-bits of ciphered data is embedded randomly in the last 3-bits of the red and blue planes of the colored cover image as the scattered LSB in the 1st proposed technique, also it is applied on a gray cover image to compare the two techniques.
The Objectives:
1-The main objective of this study is to keep pace with the digital evolution and the poverty of the time in people by designing a system that secures digital handwritten signatures to be kept from forgery.
2-The handwritten signature secure is made by using data hiding techniques (both cryptography and steganography).
The Results:
1-The suggested system is implemented in MATLAB and evaluated using a variety of performance measures, including Peak Signal to Noise Ratio (PSNR), mean square error (MSE), structural similarity (SSIM), structural component (SC), and others. The suggested model demonstrates its ability to conceal private handwritten information into a conveyed cover image with excellent imperceptibility and robustness in the presence and absence of threats, according to the results.
2-The 1st Proposed technique (Hybrid-RSA) improves high security due to using hybridization of RSA and Scattered LSB. And it provides an acceptable quality of PSNR greater than 30 dB.
3-The 2nd proposed (Blowfish-MLSB) provides high quality than 1st and other techniques. Regarding to PSNR, SSIM, and MSE.
4-The 2nd proposed provides high security measures comparing to other related work, this due to the robustness provided Blowfish algorithm.
5-The 2nd proposed provides faster encoding/decoding comparing to other related work, this due to the robustness provided Blowfish algorithm.
The Recommendation / Future Work:
Other parts of our planned system that we are looking forward to working on in the future include:
1-Applying optimization techniques for the decision about Bit number.
2-Applying image enhancement and filtering to the stego image in order to flatten the image after the image being modified.
3-Using pattern recognition methods for verifying the handwritten signature.
4-Using coverless to embed the signature.