In Greek steganography this is called as “covered writing”, which is the science of communication using hidden information. To analyze the existing techniques this method is introduced. This technique embeds and extracts the hidden information of large length inside digital images which maintains the range and size of the original image. Without the knowledge of the original image the hidden message can be recovered using the suitable keys. Methods related to speed spectrum like image restoration and error control methods are explained and the presentation of the system is showed.
This cipher is a form of polyalphabetic substitution. In this cipher we make a key before encrypting the message so that it is a bit more secure. In this method the key shifts the alphabets according to its position. In this encryption the key needs to be known for the person decrypting it because there are about 26n possibilities where n is the number of letters in the string. For example let the code be: “mybirthdayisinjanuary” and let’s take the key to be “math” Plain Text m y b i r t h d a y i s i n j a n u a r y Key m a t h m a t h m a t h m a t h m a t h m Encrypted Text y y u p d t a k m y b z u n c h z u t y k Thus the encrypted text cannot be broken easily and if someone tried without a key there are 265 ≈ 1.2 X 107 possibilities unlike the Caesar cipher with just 25 possibilities.
This means that as the information is loaded or saved it is being decrypted or encrypted. Any piece of hardware with the correct key can read entire volumes of encrypted information by immediately decrypting it. Without the key hardware it will be impossible for it to read the encrypted information. In order for this process to be completely transparent to the user the computer needs the use of device drivers that activate the encryption process. Any type of information that is encrypted as it is written and decrypted as it is read is on-the-fly encryption.
Line extraction techniques may be categorized as projection based, grouping, smearing and Hough-based. . The proposed algorithms that address the above-mentioned processing stages come mainly from the fields of image processing, computer vision, machine learning and pattern recognition. Actually, some of these algorithms are very effective in processing machine printed document images and therefore they have been incorporated in the workflows of well-known OCR systems. Text line segmentation is a critical stage in layout analysis, upon which further tasks such as word segmentation, grouping of text lines into paragraphs, characterization of text lines as titles, headings, footnotes, etc.
Considering the above parameters, Cryptographic algorithms and protocol are very useful to keep a network system secure. “Cryptography” is an art and science of providing information by transferring it into an unreadable format which can be only read by the expected receiver having the secret key to break the message. It can be defined as a science that applies complex mathematics and logic to design strong encryption
Several image segmentation algorithms were proposed to segment an image before recognition or compression. This paper focuses towards highlighting the strength and limitations of earlier proposed classification techniques discussed in the contemporary literature. This paper
F1' replace the left half of the message and P1' replace the right half . 9. The process is repeated 15 more times with successive members of the P-array. 10. The resulting P16' and F16' after 16 round are then XORed with the last two entries in the p-array (entries P17 and P18 ) and recombined to produce the 64 bit cipher text of the message “HI world “, a graphical representation of function (F) appears in figure
Steganography has been also categorized as cryptography by many authors because hiding a message is considered as somekind of secret writing. The main types of steganography are Technical Steganography and Linguistic Steganography. We will not go deeper in describing these types since as mentioned Steganography is not the main theme of the discussion in this document. 3.2 Digital Watermarking Digital watermark also known as forensic watermark is a peace of code embedded into an image document or video and it can be visible or invisible. Main aim of digital watermark is to protect the authenticity of a document and its author
This algorithm can take input as either individual pixels or regions and points these inputs to some region formed by the algorithm. The algorithms explains two methods in which input corresponds to region, either by using manual seed or by automated procedure. Chakraborty et al., (1996) , proposed a method which combines region based segmentation and boundary finding to form new method which is more robust to noise and high performance. The literature covered above is some general segmentation algorithms which will apply for any types of images. In literature there are many studies available, which mainly focuses on fingerprint image
The certificate holder has to hold the private key securely. The digital certificate operates when the sender wants to send the message or data would request the receiver’s digital certificate which contains the public key from the original source. During this stage, private key is used to encrypt the message or data before sending to the receiver. After that, the encrypted message can only be decrypted by receiver’s public key. According to Kovinic (2011), the data contains in the digital certificate are digitally signed and then confirmed by the Certification Authority (CA).