Computer World. Матросова Т.А. - 106 стр.

UptoLike

ВУЗ: 

УлГТУ | Ульяновск

Составители: 

Рубрика: 

105
MIT Professor Ronald Rivest has observed that the controversy over
cryptography fundamentally boils down to one question: should the c itizens of a
country have the right to create and store documents which their government cannot
read?
What Is Encryption?
Encryption is a process by which a message (called plaintext) is transformed
into another message (called ciphertext) using a mathematical function and a special
encryption password, called the key.
Decryption is the reverse process: the ciphertext is transformed back into the
original plaintext using a mathematical function and a key.
Indeed, the only way to decrypt the encrypted message and get printable text is
by knowing the secret key nosmis. If you don't know the key, and you don't have
access to a supercomputer, you can't decrypt the text. If you use a strong encryption
system, even the supercomputer won't help you.
What You Can Do with Encryption
Encryption can play a very important role in your day-to-day computing and
communicating:
• Encryption can protect information stored on your computer from unauthorized
access – even from people who otherwise have access to your computer
system.
• Encryption can protect information while it is in transit from one computer
system to another.
• Encryption can be used to deter and detect accidental or intentional alterations
in your data.
• Encryption can be used to verify whether or not the author of a document is
really who you think it is.
Despite these advantages, encryption has its limits:
• Encryption can't prevent an attacker from deleting your data altogether.
• An attacker can compromise the encryption program itself. The attacker might
modify the program to use a key different from the one you provide, or might
rec ord all of the enc ryption keys in a spec ial file for later retrieval.
• An attacker might find a previously unknown and relatively easy way to
decode messages encrypted with the algorithm you are using.
• An attacker could access your file before it is encrypted or after it is decrypted.
For all these reasons, encryption should be viewed as a part of your overall
computer security strategy, but not as a substitute for other measures such as proper
access controls.

Страницы