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Beyond the DES in .NET Connect barcode standards 128 in .NET Beyond the DES




How to generate, print barcode using .NET, Java sdk library control with example project source code free download:
Beyond the DES using barcode drawer for vs .net control to generate, create ansi/aim code 128 image in vs .net applications. Specific Terms for GS1 Barcodes The original DES was g .NET barcode 128 iven of cial US Government Approval for about 10 years. After that time triple DES, as described above, continued to be approved but, in addition, new encryption algorithms were sought.

In 1993 an algorithm called Skipjack was authorised and implemented on a chip known as Clipper. The details of the Skipjack algorithm were initially kept secret but were declassi ed on June 24th 1998 [13.7].

An unof cial encryption system (i.e. one that was developed by private individuals) that has attracted many users is PGP, which is short for Pretty Good Privacy .

PGP was developed by Philip Zimmermann and is freely available to anyone who wants it. It involves the following steps:. (1) a random key is generated based upon the user s movements of the mouse and keystrokes; this is referred to as the session key; (2) the plaintext of the message is compressed; the extent of compression depends upon the nature and length of the text; a typical English text might be compressed by 50% without introducing ambiguities but for short texts the saving, in transmission time, may not be worthwhile; (3) the key generated in (1) is used to encipher the compressed text produced in (2) using an algorithm called IDEA ( International Data Encryption Algorithm ) invented by Lai and Massey at ETH, Zurich [13.8];. chapter 13 (4) the session key is now encrypted using the public key of the recipient; (5) the encrypted session key is placed at the front of the encrypted text and the whole sent to the recipient; (6) on receiving the encrypted text the recipient rst uses his private key to decrypt the session key at the beginning of the text; (7) with this decrypted key he can now decrypt the message text, and decompress it if necessary.. As in the case of RSA Visual Studio .NET barcode standards 128 followed by DES mentioned above, the use of two encryption systems in PGP not only increases security, it also considerably increases speed because the time taken to encrypt or decrypt using a system where the encryption/decryption keys are essentially the same is far less than the time required to encrypt/decrypt in a public key system, such as RSA, where the keys are totally different. In PGP only the relatively short session key is encrypted by a public key system; the text itself is encrypted by a non-public key system (IDEA).

PGP and related topics have led to thousands of articles that can be found on the internet. Anyone who wants more details should consult [13.10], [13.

11]. Encryption algorithms for public use have been the subject of a great deal of research and it is to be expected that this will continue..

Authentication and signature veri cation As was mentioned earli Code 128 Code Set B for .NET er, these problems can be solved using public key systems. The DES is not such a system but the RSA method is.

Recall that in a public key system each user has a public (encipherment) key, E, and a secret (decipherment) key D. Let us suppose that X wishes to send a message, M, to Y and that EX, DX, EY and DY are the encipherment and decipherment keys of X and Y respectively. How can:.

(1) Y be sure that the message has been sent by X (2) X ensure that Y cannot claim to have received a different message, M , say (3) Y ensure that X cannot claim that he sent a different message, M , say . There are several ways visual .net Code 128 Code Set C of solving these problems, all of them involve using some or all of the encipherment and decipherment keys. A typical solution is:.

Encipherment and the internet (1) X precedes M with VS .NET code 128 barcode information which includes the date and time as well as his identity, thus M is extended to a longer message M1, say, which is something like M1: I am X, the date is 13-06-2001 and the time is 1827. M where M is the original message.

(2) X decrypts M1 using his private key, DX , producing a cipher message DX(M1) which he sends to Y. (3) Y applies X s public encipherment key, EX, to this cipher message and so recovers the extended message, M1, since EX(DX(M1)) M1..

Now:. (1) Y can be sure that Code-128 for .NET X sent M1 since only X can produce DX(M1). (2) If Y claims that he received a different message, M , X challenges Y to produce the cipher text DX(M ).

Y will be unable to do this since he doesn t know X s secret key, DX. (3) If X claims that he sent a different message, M , to Y the latter can show the cipher message, DX(M1), to a judge who will ask X for his secret key so that he can check whether the message M1 was sent. Since Y doesn t know X s secret key he couldn t have constructed DX(M1).

If X refuses to give his secret key to the judge he will lose his case.. It is important that t he extended message M1 includes the date and time otherwise an old message could be substituted for M1 which would invalidate the point made in (2) above..
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