Jeffrey Richter is a cofounder of Wintellect, a training, debugging, and consulting firm dedicated to helping companies build better software, faster. NET column.
He has been consulting with Microsoft's. NET Framework team since October Abstract: This talk explains how compilers produce metadata and how this metadata is used by the CLR to resolve type references. In this talk, we'll walk through the process of building an assembly and discuss how the CLR locates dependant assemblies avoiding the need for the registry. Then, we'll discuss how to create and deploy shared assemblies containing shared components.
See www. Paul D. Contact Paul directly at PSheriff pdsa. This session will cover how to create an ASP. Integrity: Integrity means that the content of the communicated data is assured to be free from any type of modification between the end points sender and receiver. The basic form of integrity is packet check sum in IPv4 packets. Non-Repudiation: This function implies that neither the sender nor the receiver can falsely deny that they have sent a certain message.
Service Reliability and Availability: Since secure systems usually get attacked by intruders, which may affect their availability and type of service to their users. Such systems should provide a way to grant their users the quality of service they expect.
One of the main categorization methods for encryption techniques commonly used is based on the form of the input data they operate on. The two types are Block Cipher and Stream Cipher. This section discusses the main features in the two types, operation mode, and compares between them in terms of security and performance. Before starting to describe the key characteristics of block cipher, the definition of cipher word must be presented.
In this method data is encrypted and decrypted if data is in from of blocks. In its simplest mode, you divide the plain text into blocks which are then fed into the cipher system to produce blocks of cipher text. ECB Electronic Codebook Mode is the basic form of clock cipher where data blocks are encrypted directly to generate its correspondent ciphered blocks shown in Fig. More discussion about modes of operations will be discussed later.
Stream cipher functions on a stream of data by operating on it bit by bit. Stream cipher consists of two major components: a key stream generator, and a mixing function. Mixing function is usually just an XOR function, while key stream generator is the main unit in stream cipher encryption technique. For example, if the key stream generator produces a series of zeros, the outputted ciphered stream will be identical to the original plain text.
Figure 3 shows the operation of the simple mode in stream cipher. There are many variances of block cipher, where different techniques are used to strengthen the security of the system.
ECB mode is the CBC mode uses the cipher block from the previous step of encryption in the current one, which forms a chain-like encryption process. OFB operates on plain text in away similar to stream cipher that will be described below, where the encryption key used in every step depends on the encryption key from the previous step. These two categories are: Asymmetric and Symmetric encryption techniques. In this type of encryption, the sender and the receiver agree on a secret shared key. Then they use this secret key to encrypt and decrypt their sent messages.
Node A and B first agree on the encryption technique to be used in encryption and decryption of communicated data. Then they agree on the secret key that both of them will use in this connection. After the encryption setup finishes, node A starts sending its data encrypted with the shared key, on the other side node B uses the same key to decrypt the encrypted messages.
The main concern behind symmetric encryption is how to share the secret key securely between the two peers. If the key gets known for any reason, the whole system collapses. Asymmetric encryption is the other type of encryption where two keys are used. To explain more, what Key1 can encrypt only Key2 can decrypt, and vice versa. It is also known as Public Key Cryptography PKC , because users tend to use two keys: public key, which is known to the public, and private key which is known only to the user.
Figure 5 below illustrates the use of the two keys between node A and node B. After agreeing on the type of encryption to be used in the connection, node B sends its public key to node A. Node A uses the received public key to encrypt its messages. Then when the encrypted messages arrive, node B uses its private key to decrypt them. This capability surmounts the symmetric encryption problem of managing secret keys.
But on the other hand, this unique feature of public key encryption makes it mathematically more prone to attacks. Moreover, asymmetric encryption techniques are almost times slower than symmetric techniques, because they require more computational processing power [Edney] [ Hardjono ].
To get the benefits of both methods, a hybrid technique is usually used. In this technique, asymmetric encryption is used to exchange the secret key, symmetric encryption is then used to transfer data between sender and receiver. This section intends to give the readers the necessary background to understand the key differences between the compared algorithms. It is based on the IBM proposed algorithm called Lucifer.
DES became a standard in [ TropSoft ]. Since that time, many attacks and methods recorded that exploit the weaknesses of DES, which made it an insecure block cipher. In this standard the encryption method is similar to the one in original DES but applied 3 times to increase the encryption level.
But it is a known fact that 3DES is slower than other block cipher methods. For Daily Alerts. Don't Miss! Trending Related Most Read. Do not Disturb. Click to comments. Notification Settings X Time Settings. Clear My notification inbox.
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