# Computer Cryptography

Types of cryptography and how it helps in protecting your computer.

Cryptography is defined as the science of analyzing and deciphering codes, ciphers and cryptograms. Cryptography consists of theories and concepts which belong to different disciplines such as mathematics, computer science and engineering. The concept of cryptography is applied in various applications and fields such as in ATM cards, computer passwords, electronic commerce etc. Using cryptography, the ordinary text can be transformed into a coded form which is known as cipher text. So, computer cryptography is the use of these codes to protect the computer from unwarranted access by intruders. Cryptography makes use of a specific parameter called key which is used secretively during a specific exchange of messages. So with cryptography you save your computer from hackers and other anti-security activities by blocking access to intruders. This implies that for you to fully secure your computer and the privacy of the data, you need cryptography as a key component.

Modern Cryptography can be of the following types:

• Symmetric Key Cryptography

• Public Key Cryptography

## Symmetric Key Cryptography

It is a kind of cryptography in which the same key is shared by both the sender and the receiver of the message. There are two kinds of symmetric key ciphers, which are block ciphers and stream ciphers. Block ciphers are defined as algorithms which make use of 2 input strings which are a block of plaintext and a key. The output which is generated by the block ciphers include a block of ciphers whose size is same as that of the block of plaintext which is fed as input into the block ciphers. It has been always seen that the size of the messages is usually more than one block. Hence, various methods are used to combine together various blocks of messages which are exchanged between the sender and the receiver.

In stream ciphers, a long sequence of characters is used as the key which is needed during the exchange of messages. This key is then added to the original message either bit by bit or character by character. The output which is generated by a stream cipher depends on the hidden internal state. The hidden internal state alters as the algorithm proceeds. The secret key is generally used in the beginning to determine the internal state.

## Public Key Cryptography

Public key cryptography makes use of asymmetric algorithms in order to generate two kinds of keys. The 2 keys which are generated using asymmetric algorithms are the secret private key and published public key. In this kind of cryptography, the private key is used to generate a digital signature of message which is used to maintain the authenticity of the message. The digital signature is verified by making use of the public key. The message is converted into ciphertext by making use of the public key. The private key has to be used in order to convert the ciphertext back into the original message. Public key cryptography is the most widely used form of cryptography these days. The cost associated with the public key algorithms is more as compared to that of the symmetric algorithms.

iYogi's Digital Home Plan

We offer comprehensive support for your PC, connected devices, peripherals and over 500 software applications including:

• Diagnostic & repair for your technologies.
• Troubleshooting software errors.
• Updating drivers and security to protect against online threats.
• Connecting to the Internet, devices and peripherals.
• Optimizing your PC's speed and performance.

Enjoy instant and unlimited access to great tech support, all year around. We promise the lowest wait-time and the highest resolution rate in the industry. The experienced and skilled technicians of iYogi are on call 24x7 to provide you support for resolving any tech issue that you are struggling with.

iYogi’s tech experts can provide support for all the major brands of laptops, like Dell, ASUS, Toshiba, Compaq, Lenovo, Dell, etc.