In this type of attacks when a CBC-encryption is used the plain text is easily recovered. As discussed above the best practice would be using ENCRYPT-THEN-MAC. In the TLS protocol padding technique is added to make the block the size multiple of cipher text. After this the block is finally encrypted with a CBC mode. In the decryption process the cipher text is taken and XOR’d with the cipher text block of the previous one and compared with that of the existing MAC [5].
Here a “Padding Oracle Attack” can be made as the padding is not secured by the MAC because in TLS protocol the padding is done after the tag is produced. Once an attack has been made, the attacker can do the padding oracle attack and can change the data. At the decryption if an error is shown which means the padding is not the exact as in the encryption process then it terminates an error message. Because in the decryption process the MAC is only verified only when the padding is validated. During this attack, depending upon the message errors occurred in the decryption the attacker predicts the message without knowing the key, while executing for several number of times and he will be successful [5].
When an estimation is done on how much time has taken to extract the plaintext block is in the range of 2^23 TLS sessions.
What is padding oracle attack?
In a symmetric key encryption the padding oracle attack is most commonly done which is considered as a “Timing side-channel attack” where the attacker knows whether during the encryption process the padding is done and executed correctly or not. If not he tries to attempt the recovery of plain text [1] [4].
(D)TLS Record protocols:
In this protocol the message to be protected is divided into blocks and then encryption functions are applied. The working of this DTLS is same as that of the TLS but here we are trying to decrease the timing side-channel [1].
Here a MAC tag ‘a’ is created for the given message. This tag length varies for different MAC functions we are using. If we are using a HMAC-MD5 then the tag length would be 16 bytes, for HMAC-SHA1 it will be 20 bytes and for HMAC-SHA256 it will be 32bytes [1].
In this a plain text is created with a Record (which is a combination of sequence of numbers and high dynamic range image) concatenated with tag produced with a valid HMAC and again concatenated with padding.
around at 4:45. This sets the time frame of the investigation. The next morning, the
d)The information is not contained in a any http message formatted can cannot say depending on the Http messages exchanges alone.
Authentication Header (AH) and Encapsulating Security Payload (ESP) are a part of the IPSec components, they are network layer protocols allowing secured communications through a VPN tunnel. Within a firewall to enable communication for AH one will use protocol 50 and for ESP protocol 51 (Frankel, Hoffman, Orebaugh & Park, 2008), both protocols 50 and 51 can be enable within the same end-to-end IPSec connection which is the Tunnel Mode connected by two gateways. Nonetheless, for Transport Mode, there are some restrictions in the order in which they appear. While AH supports connectionless integrity and authentication of the packets, ESP provides data origin authentication and confidentiality through the use of encryption, both AH and ESP provide
TGT last up to 10 hours and on other hand Service ticket last varies according to host and server.
Sabu M. Thampi, Pradeep K. Atrey, Chun I. Fan, Gregorio Martinez Perez (Eds.), Security in Computing and Communications: International Symposium, SSCC 2013, Mysore, India, August 22-24, 2013. Proceedings (Communications in Computer and Information Science) (p. 418). New York, NY: Springer Publishing.
This process is a transport layer encryption that includes HTTPS using TLS/SSL which is used to encrypt and keep secure the communication between the websites and the web browser. The websites with HTTPS, enable us to transmit the information over the internet securely. Even if unauthorized user access that information, they can’t read. When the information reaches to the destination probably located in a different country, then website operator can decrypt it and store it.
Password Authentication: client sends plaintext password to the server encrypted with the key identified in the previous steps [3].
Lv, X., Li, H., Wang, B. (2012) Virtual private key generator based escrow-free certificateless public key cryptosystem for mobile ad hoc networks ISSN: 19390114
Moebius, William. Introduction to Picturebook Codes, Word & Image, vol. 2, no. 2 (April - June 1986), pp. 141-51, 158.
Spanning tree protocol is a protocol that prevents loops that are not wanted in a network. In order for a network to work properly it has to have only one active path between two network stations. If there are multiple active paths between stations loops can and will occur. When loops occur, there can sometimes be duplicate messages in the network. The loops are created by the network and if the devices that connect the network segments are all configured to forward, they will continuously forward frames into an endless network loop. If there are enough loops going then a frame will not reach its destination. The reason duplicate messages occur is because sometimes switches will see situations appear on both sides of it. When this occurs that is when spanning tree protocol comes in. In order to shut down the loops bridges and switches exchange BPDU messages with other bridges and switches to detect loops and then remove them by shutting down selected bridge interfaces. BPDU is short for bridge protocol data unit. Bridge protocol data units are part of the spanning tree protocol and they help describe and identify the parts of a switch port. The bridge protocol data unit allows switches to obtain information about each other. All the switches gather information from each other by exchanging data messages. In order for them to exchange messages they have to elect a root switch for the topology. The root switch has to be unique. The way they elect they have to have a unique switch for every local area network segment. To exchange messages they have to remove all loops by putting them in a backup state. Now to talk about states there is 5 different states. Two of the five states do not participate in frame forwarding. Frame forwarding is what the three main states do. The three main states are listening, learning, and forwarding. The other 2 are blocking state and disabled state. When you enable the spanning tree protocol the network goes through the blocking state and then the listening state and learning state are enabled after being turned on. If the protocol is properly configured the ports are stabilized to the forwarding or blocking state. The blocking state does not participate in the frame forwarding. It removes frames that are received from the attached segment. It also discards frames from another port for forwarding.
Perhaps the most redundant, fault-tolerant of all network topologies is the mesh LAN. Each node is connected to every other node for a true point-to-point connection between every device on the network.
Data encryption refers to the transformation of data into a structure that makes it unreadable by anyone without a secret decryption key. It ensures that messages can be read only by the planned recipient. Encryption is the procedure of obscuring information to create it unreadable without special information. Only organizations and individuals with an abnormal need for secrecy have actually made good use of it. Nowadays, encryption is one of the most important technologies for maintaining your privacy and the security of important information. This helps out greatly especially when E-Commerce is being used.
In this era when the Internet provides essential communication between tens of millions of people and is being increasingly used as a tool for security becomes a tremendously important issue to deal with, So it is important to deal with it. There are many aspects to security and many applications, ranging from secure commerce and payments to private communications and protecting passwords. One essential aspect for secure communications is that of cryptography. But it is important to note that while cryptography is necessary for secure communications, it is not by itself sufficient. Cryptography is the science of writing in secret code and is an ancient art; In the old age people use to send encoded message which can be understand by the receiver only who know the symbolic and relative meaning of that encoded message .The first documented use of cryptography in writing dates back to circa 1900 B.C. Egyptian scribe used non-standard hieroglyphs in an inscription. After writing was invented cryptography appeared spontaneously with applications ranging from diplomatic missives to war-time battle plans. It is no surprise, then, that new forms of cryptography came soon after the widespread development of computer communications. In telecommunications and data cryptography is necessary when communicating in any untrusted medium, which includes any network, particularly the Internet [1].Within the context of any application-to-application communication, there are some security requirements, including:
The main MD5 message digest is represented as 16-byte (128-bits) Hexadecimal number ( written as 32 characters using the digits 0-9 and A-F or a-f ). This value can be found all over the internet. The checksum is a type of redundancy check that will verify the data in a number of ways. MD5 allows a string of unique letters and numbers to stand for data. MD5 can be used across all platforms making it universal. You can use it with windows, or any other operating system that you wish. I myself used it on Windows XP and it worked flawlessly.
Rayne, PB, Kulkarni, P, Patil, S & Meshram, BB 2012, ‘Authentication and Authorization:Tool for Ecommerce Security’, Engineering Science and Technology: An International Journal, vol. 2, no. 1, pp. 150-157.