While it is remarkable for its simplicity and speed in software, multiple vulnerabilities have been discovered in RC4, rendering it insecure. As of [update] , there is speculation that some state cryptologic agencies may possess the capability to break RC4 when used in the TLS protocol. RC4 was initially a trade secret , but in September a description of it was anonymously posted to the Cypherpunks mailing list. The leaked code was confirmed to be genuine as its output was found to match that of proprietary software using licensed RC4.

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Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our User Agreement and Privacy Policy. See our Privacy Policy and User Agreement for details. Published on Jun 22, In this study, we are doing a cryptography scheme which can modify the visualization of pictures. The protection of images is critical. This protection does not alter the value of the header and the metadata.

Every image consists of three color layers. There are red, green and blue. Each layer has numbers which represent the color intensity. RC4 is used to change the color intensity in every layer. We can choose how many layers will be encrypted. The fuzziness of the encrypted image depends on how many layer are taking a role.

SlideShare Explore Search You. Submit Search. Successfully reported this slideshow. We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime. RC4 Technique in Visual Cryptography. Upcoming SlideShare. Like this document? Why not share! Un algorithme de chiffrement a flot Embed Size px. Start on. Show related SlideShares at end.

WordPress Shortcode. Universitas Pembangunan Panca Budi Follow. Published in: Education. Full Name Comment goes here. Are you sure you want to Yes No. Be the first to like this. No Downloads. Views Total views. Actions Shares. Embeds 0 No embeds. No notes for slide. RC4 Technique in Visual Cryptography 1. Gatot Subroto Km. The image protection is very critical.

It does not alter the value of the header and the metadata. We are just trying to modify the color intensities. There are red, green and blue RGB. Each layer has numbers which represent the intensity. The encryption process it to manipulate the integer number and produce the encrypted value. We determine how many layers is going to be encrypted.

The fuzziness of the encrypted image depends on how many layer are included. The visualization will be unrecognized after the encryption. It changes to a noisy picture. This method makes the image content secure and undetected. It proves what someone has done. It contains the confidential information. If it fell into the perpetrator, it will be a big problem.

We must hide the information from being intercepted. There are various techniques should be used to protect the confidential image data from unauthorized access [2]. Visual Cryptography can be combined with Steganography, but, in Steganography, it usually changes the bit pattern for increasing the security of the image [4].

Our target is to manipulate the image visualization. The image consists of integer number that represents the color intensity. The method proposes is the encryption that transforms the original image into to coded image.

So it is hard to understand. In the other word, someone might take it, but they do not understand, or they cannot decrypt the content of the picture without having the key. Visual Cryptography Visual Cryptography is one of the cryptography methods to hide the information. It usually uses pictures and other multimedia [2][6]. The example is when we subscribe to the TV station.

If we late to pay the subscription fee, they will encrypt the broadcast. We still can see on TV, but we do not know what is the meaning of the pattern showed. Yes, of course, they scramble the broadcast. The previous example is one of the visual cryptography implementation. The encryption in visual cryptography does not use hard mathematical computations to perform encryption and decryption. The original information going to encrypt is a secret message. After encryption, ciphers are generated and referred as shares.

The part of a secret in scrambled form is known as a share. The basic idea in visual cryptography is to share the secret among participants. It is divided into several pieces of images. They are shares. These are distributed among the participants.

To reveal the first secret, each participant provides his share. There is a various scheme of visual cryptographic available. There is 2 out of 2 visual cryptography where the message is split into two images.

These two shares must participate to retrieve the secret message [1]. Adi Shamir invented the secret sharing concept of visual cryptography in He stated that it is divided into several pieces and easily reconstructive from any pieces. He claimed that data is protected by encryption, but the key used for encryption could not be covered. He wrote that secret sharing aimed to protect the keys used to encryption.

Depending on Shamir, the scheme is k out of n secret sharing scheme [3]. Figure 1 shows the example of visual cryptography scheme. Figure 1 : Example of visual cryptography In figure 1, the graying effect is noted in the background. Additional black pixels in the background are forming some pattern and giving rise 2. Owing to this effect, the meaning of secret remains undisturbed. Hence, the graying effect has no impact on the first secret. Another scheme knew as 2 out of n scheme.

The secret is structured in exactly n shares. At least, two shares must participate. The third scheme of VC is formally known as K out of n scheme in which the secret is structured in exactly n parts. Multiple shares are generated out of visual cryptography. An extended version of the third visual cryptography scheme is n out of n where in secret is split into several n shares.

They must participate while revealing the secret. Hierarchical visual cryptography abbreviated is the specialization of visual cryptographic schemes.


Symmetric-key algorithm

Symmetric-key algorithms [a] are algorithms for cryptography that use the same cryptographic keys for both encryption of plaintext and decryption of ciphertext. The keys may be identical or there may be a simple transformation to go between the two keys. Symmetric-key encryption can use either stream ciphers or block ciphers. Symmetric ciphers are commonly used to achieve other cryptographic primitives than just encryption. Encrypting a message does not guarantee that this message is not changed while encrypted. Hence often a message authentication code is added to a ciphertext to ensure that changes to the ciphertext will be noted by the receiver.


RC4 is now disabled in Microsoft Edge and Internet Explorer 11



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