Introduction to PGP for Windows introduction

I. Preface: With the vigorous development of the Internet network, the application of various networks continue to be new, in our daily life, whether it is a routine or office business, the network for you and I, is already an indispensable part of life! There are many times when we need to use the help of the Internet to disseminate messages or to information we want through the Internet. The network is so convenient and easy to use, but have you ever worried: if it is important and extremely confidential information, in the vast network of the sea, how to ensure the security and confidentiality of information? Yes, information security is a very important subject. The establishment of the Internet is not an ambiguous request, only in the information security of the foundation, we can rest assured that the important information delivered to the network, so that the network can make more diversified applications, such as network tax, e-commerce and so on. In view of this, the computing center began to carry out the public Key Infrastructure Program (Web site: http://www.sinica.edu.tw/cc/netsrv/pks.html), in order to promote the hospital key encryption system cryptosystems). First of all, as an example of the center Tongren salary notice, we will change the traditional payroll to the encrypted e-mail sent, the recipient must use the private key and password to interpret. PKI can basically achieve the function of file encryption and electronic signature, in other words, the file is encrypted with the recipient's public key, only the recipient of the private key can interpret, even if the file is stolen is not afraid of data leakage; Furthermore, the sender with the private key to the text of the copy, after the recipient, to the sender of the public key accounting, If unanimous, the document is indeed issued by the other party and has not been tampered with. In this program, the most critical cryptography technology part, we recommend the use of PGP (pretty-Privacy) system as the core. This article will be detailed in the following parts: 1. PGP Operation Introduction: Symmetric and asymmetric cipher system. 2. The installation and use of PGP for Windows software. 3. For example, how to interpret the email software. If you would like to know more about PGP encryption and decryption technology and related information, please enter our collation of the PGP Reference page (http://www.sinica.edu.tw/cc/netsrv/security/pgp.html), where the domestic and foreign PGP related sites collected , rich in content, easy to understand, as long as a little study, must benefit a lot, and you will know, in the current cryptography technology, PGP is indeed a mature, reassuring use of encryption and decryption tools. Two. PGP Operation Brief Introduction ※ part of this section extracts from the Institute of Electrical Engineering and Research Institute Ching "electronic file Exchange and public key base disk construction (i)" (http://www.gss.com.tw/gsseis/11/fa.htm) has a full text. Symmetric cryptographic system symmetric key cryptography, has a long history, the speed of encryption/decryption is its advantages, however, because of its encryption key and decryption key is the same gold key, how the sender of information after encryption, the encryption key in a secure way to the receiver, how to enable both parties to share the secret key to facilitate its decryption, is a big problem in this cryptography system, so symmetric key cryptography is less suitable for many people. The famous symmetric key cryptography algorithm has DES, RC2, RC4, Idea, GOST, SAFER, FEAL, skipjack, Blowfish, etc. ﹝schneier, B.1996﹞, the choice of the key security length of the symmetric key cryptography system can be referred to blaze and other people's research ﹝blaze,m.et Al.1996﹞. 498) this.width=498 ' OnMouseWheel = ' javascript:return big (This) ' src= ' http://images.51cto.com/files/uploadimg/ 20051219/0208430.gif "> Fig. 2.1 The problem of symmetric key cipher system asymmetric cryptographic systems, which are generally called" Public key Cryptography ", have improved the disadvantage of symmetric key cryptography, and their cryptographic keys are not the same as the decryption keys. Each pair of keys (key Pair) contains two mutually corresponding keys, one for the public cryptographic key (hereinafter called "Public Key",public key ") and a decryption key that must remain confidential (hereinafter referred to as" private key ",private key"). Slow operation is the disadvantage of public key cryptography, and RSA, for example, is about 1000 times to 5,000 times times ﹝pfleeger,c.p.1997﹞ than the symmetric key cipher system. When used, any person may disclose its cryptographic key to the person who may be communicating with it, and when any person wishes to transmit the message to the receiver, the message can be encrypted by using the "Public Key" published by the receiver and then transmitted. The encrypted message, only the established receiver has the corresponding public key to the "private key" can decrypt the message, so the public key cryptosystem can reach the two sides of the strangers, do not need to exchange the key in advance to engage in secret communication characteristics. Conversely, when the message is encrypted with the sender's "private key", any person who has a "public key" corresponding to the "private key" can decrypt it, but the "private key" is owned by the sender and remains confidential and is not disclosed, so the message encrypted with the private key may be considered as a signature to the message. But the public key cipher system is slow in operation, in practice, the signature isThe document "Remit of documents" (message Digest) is signed in lieu of signing the whole document. "Document sinks" must be able to condense any length of the message into a fixed-length message digest, and must have sufficient properties to distinguish the file, generally using cryptography with the "irreversible" and "collision-resistant (collision-resistant)" Characteristics of a safe hash function, To calculate the document sinks. The current common functions include the MD2 of RSA MD Family, MD4, MD5, the National Bureau of Standards (NIST) SHA, SHA-1, ripe, RIPEMD and RIPEMD-128 of the EU RIPEMD-160 project. RSA company has publicly declared that s24 MD2, MD4 and MD5 are not entirely suitable for use in future electronic document signature applications, and that the document transfer function recommended for future signatures is SHA-1 and Ripemd-160﹝rsa 1996b, 1996c﹞. The famous public key cipher system and digital Signature algorithm include Deffi-hellman, RSA, DSA, ElGamal, Knapsack, Rabin ﹝rsa Laboratories. Based on the public key cryptosystem, no prior exchange of the key is required. Can engage in secret communication advantages and realize the characteristics of digital signature, at present on the open network, the most commonly used method is to use the so-called public key cryptography system, to the transmission of information to encrypt or seal. In practical applications, based on efficiency considerations, generally with the public key cryptosystem with the use of symmetric key cryptography, that is, the use of symmetric key cryptosystem encryption to transmit information, and then the "symmetric encryption key" to the receiver public key cryptosystem "public key" encryption, composed of the so-called " Electronic envelope, and pass the key to a fair third party for safekeeping, and then transmit the electronic envelope to the receiver. The receiver must first use its own "private key" to seal the electronic envelope to obtain the "symmetric key decryption key", and then the symmetric key to decrypt the key to solve the real message, taking into account the convenience and efficiency. This shows that the public key cryptography system plays an important role in communication.  Figure 2.2 is the public key cryptography and symmetric key cryptography system integration application. 498) this.width=498 ' OnMouseWheel = ' javascript:return big (This) ' src= ' http://images.51cto.com/files/uploadimg/ 20051219/0208431.gif "> Fig. 2.2 Public key cryptosystem and symmetric key cipher system integration application three. About PGP (Pretty PrIvacy PGP, which was published by the original author Philip Zimmermann in 1991, was immediately compelling, and PGP is the most widely used software package in modern cryptography-related products. Because on the one hand, he used the world's cryptography experts recognized the most secure and most trustworthy of several basic cryptographic algorithms, such as idea symmetric file encryption algorithm, RSA or Diffie asymmetric encryption algorithm to deal with the public key and private key plus decryption, and the use of SHA1 The one-way hash function is used in document labeling and electronic signature authentication. These cryptographic algorithms are already publicly published, and have been repeatedly calculated by scholars to verify the encryption and decryption algorithm. The authors of PGP have integrated and programmed these cryptography techniques into a very useful package. On the other hand, PGP authors use all public (including their program raw code), and is a global free software (note) distribution, not to doubt that there will be the so-called program Hidden Door (trapdoor) exists, so deeper to the trust of the global majority of users. In the study of PGP related technology, I also dabble in the course of its development, and found it very interesting. Because the U.S. authorities have been strict restrictions on the export of ciphers, Zimmermann without the U.S. government's permission to distribute PGP around the world, and caused the popularity, so over the years he has been the official prosecution of the object, until 1996 to release the prosecution. So in the version of PGP 2.X.I will be the original program to circumvent the U.S. legal restrictions, but the 1997 release of PGP 5.0i is the first legally exported version of the United States, so that the world's love users can be assured to use, why? Because he printed the original code of the program (12 large, more than 6000 pages), and then legally exported to foreign countries, in Europe by enthusiastic volunteers, the book electronically scanned, translated back to the program code, and then compiled into the original PGP 5.0. It's hard to imagine the whole process, but it's tricky to avoid US legal norms. After the PGP 5.5.3i is also issued in the same method, this section called "the PGPI scanning project" process, detailed in http://www.pgpi.com/project/. It is also emphasized that all file scanning work has been completed and no volunteer support is required at this time. So when we enjoy the PGP feast, please remember the courage of Zimmermann and the dedication of a group of enthusiastic volunteers behind the scenes. (note) PGP Latest News Network on PGP information is very rich, the most important site is pgpi.com (http://www.pgpi.com), here will update PGP information, and provide a variety of operating systemsThe latest version of PGP software, we can choose "download pgp" Layout on the page, then specify the version you want: The U.S. version or international version, operating system, free or commercial version, and so on, you will know the latest version of PGP message, finally choose the nearest FTP station to pass, very convenient. For example: Non-U.S. users, free PGP in the latest version of the WINDOWS/MAC environment is PGP 5.5.3i, the latest version of the Unix environment is PGP 5.0i. This article will continue to introduce the installation and use of PGP 5.5.3i for Windows. 498) this.width=498 ' OnMouseWheel = ' javascript:return big (This) ' src= ' http://images.51cto.com/files/uploadimg/ 20051219/0208432.gif "> Map 3.1 pgpi.com website offers various versions of PGP to force (0 votes) (0 votes) of the nonsense (0 Votes) Professional (0 Votes) The title party (0 Votes) passing (0 Votes) Original: PGP for Windows Introduction Back to network security home