Definition: Cryptography - the discipline that embodies the principles, means, and methods for transforming data in order to conceal its semantic content, prevent unauthorized use, or prevent undetected modification.
The process of converting ordinary plain text into unintelligible text and vice versa is known as cryptography. It is a method of storing and transmitting data in a specific format so that only those who are intended to read and process it can do so.
In general, there are three types of cryptographic algorithm techniques used:
1. Asymmetric-key cryptography (also known as Public-key cryptography)
Two related keys (public and private key) are used in public-key cryptography. The public key can be freely distributed, whereas the private key must be kept secret. The public key is used for encryption, and the private key is used for decryption. Asymmetric algorithms are used for:
- Authenticating data using digital signatures
- Establishing cryptographic keying material
- Identity management
- Encrypted email where a public key encrypts a message, the private key decrypts it
- Establishing encrypted links between websites and browsers SSL/ TLS
2. Symmetric-key cryptography
A single key is shared by both the sender and the receiver. This key is used by the sender to encrypt plaintext and send it to the receiver as cypher text. The receiver, on the other hand, uses the same key to decrypt the message and recover the plain text.
Asymmetric encryption versus
Symmetric encryption Symmetric encryption uses the same key to perform both encryption and decryption functions.The length of the keys in symmetric cryptography is typically set at 128 bits or 256 bits, depending on the level of security required.
In asymmetric encryption, there must be a mathematical relationship between the public and private keys. Since malicious actors can potentially exploit this pattern to crack the encryption, asymmetric keys must be longer in order to provide the same level of security and therefore, the difference in key length is so significant that a 2048-bit asymmetric key and a 128-bit symmetric key provide roughly the same level of security.
3. Hash functions
No key is used in this algorithm. A fixed-length hash value is computed based on the plain text, making it impossible to recover the plain text's contents. Many operating systems use hash functions to encrypt passwords.