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#1
 
 
Cryptography and Public Key Infrastructure I want to know about the Cryptography and Public Key Infrastructure. Last time, you members have explained properly about my query, so I thought to ask my question over here instead of searching on net. Please provide some detailed information about the topic. Any other notes regarding the topic would be grateful. I am expecting that discussion should be in detail so that I can gain much knowledge. 
#2
 
 
Re: Cryptography and Public Key Infrastructure Cryptography is fundamentally based on mathematical functions and indepth study would lead us directly to mathematical research, which is not the objective at this time. Cryptographic methods are based on mathematical algorithms (functions) such that applied to certain data (the information) plus a variable argument produce a given output unreadable (ciphertext). In general terms used Plain Text (readable information), Key (the argument variable) and ciphertext (encrypted information). 
#3
 
 
Re: Cryptography and Public Key Infrastructure Cryptography is one of the methods to protect confidential information. This paper will be defined as a set of mathematical techniques for protecting information by certain properties, which define the most important. We must bear in mind that some of them are provided by cryptographic means and / or encrypted. 
#4
 
 
Re: Cryptography and Public Key Infrastructure The following are the Properties of Cryptography :

#5
 
 
Re: Cryptography and Public Key Infrastructure I would like to discuss about the cryptographic functions. Mathematical algorithms (functions) used in cryptography meet certain conditions, including the fundamental means that is simple computer in a sense, and virtually impossible in the opposite direction, without knowing any of the information. Let's clarify this: in Plaintext + Key + algorithm is easy to obtain the ciphertext. But knowing Text + encryption algorithm, it is almost impossible to obtain the plain text, without knowing the password. The algorithms used are known publicly, the difficulty is not knowing the key. 
#6
 
 
Re: Cryptography and Public Key Infrastructure Hash functions are also involved. These functions take a variable length input (Plaintext) and produce a fixed length output (hash). Whose priority is a "small" change in input produces a "large" change in the output. Anyway we must remember that "reduce" the entrance to a fixed length output, and generally shorter, it is always possible that different inputs produce the same result, this is called collision. Meet the condition that in the event of a collision entries are so different that it is easy to see that do not correspond. 
#7
 
 
Re: Cryptography and Public Key Infrastructure When using a symmetric key scheme, also called the Secret Sharing method uses the same key to encrypt and decrypt information. The key concept to remember is that the key used to encrypt, is used to decrypt it, therefore the algorithms used are complementary. This scheme has advantages and disadvantages. Among the advantages we can mention the ease of implementation and among the disadvantages that if you agree to the Key, at either end, you get the ability to encrypt and decrypt. 
#8
 
 
Re: Cryptography and Public Key Infrastructure The asymmetric key scheme greatly improves the security of the previous case, but its implementation is more complex. The Public Key scheme is based on each entity has two keys that meet the following conditions:

#9
 
 
Re: Cryptography and Public Key Infrastructure I would like to give an example to clarify the use, such as a sending a message.

#10
 
 
Re: Cryptography and Public Key Infrastructure The Digital Signature process whose main function is to ensure the integrity of the information and may also provide nonrepudiation and authentication. Digital Signature Process is usually used in combination with a public key scheme, a way to encrypt the hash. If this can not happen, it would be easy for someone intercepting the message to alter the content and calculate the new hash. It is noteworthy that the digital signature does not provide encryption, if necessary the latter must be combined with an encryption technique. 
#11
 
 
Re: Cryptography and Public Key Infrastructure Quote:

#12
 
 
Re: Cryptography and Public Key Infrastructure One of the key components of the scheme is public key certificate. The certificate is a reliable way to verify the correspondence between a name and its corresponding public key. Although it contains much more data in the first instance we can say that a certificate reads something like:

#13
 
 
Re: Cryptography and Public Key Infrastructure Quote:

#14
 
 
Re: Cryptography and Public Key Infrastructure Quote:

#15
 
 
Re: Cryptography and Public Key Infrastructure The contents of a certificate in detail is beyond the scope of this note, but we'll see some of the important data it contains. Recall that the main use is to verify the correspondence between the name of the person was given and the corresponding public key. Some of the fields it contains are:


Tags: authentication, ciphertext, cryptography, encryption, infrastructure, ipsec, public key 
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