Symmetric Encryption
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Symmetric key cryptography (or symmetric encryption) is a type of scheme in which the same key is used both to encrypt and decrypt messages. Such a method of encoding information has been largely used in the past decades to facilitate secret communication between governments and militaries. Nowadays, symmetric key algorithms are widely applied in various types of computer systems to enhance data security.
Symmetric encryption relies on the usage of a single key by several users. Plaintext is encrypted with a unique key and decrypted using the same key (which represents the message or piece of data that is being encoded). Using a cipher, an encryption algorithm, a plaintext (input) is processed through the algorithm, which yields the output (ciphertext) (output).
To decrypt the ciphertext, one must have the associated key, which is only possible if the encryption technique is robust enough. Decryption is the process of recovering the original plaintext from the ciphertext.
Based on how difficult it is to guess the corresponding key, symmetric encryption techniques are more secure. Common computer gear would take billions of years to crack a 128-bit key. The longer the encryption key, the more difficult it is to decipher it. Theoretically, quantum computer brute force assaults cannot crack keys longer than 256 bits in length.
Block and stream ciphers are two of the most common symmetric encryption techniques in use today. For each individual block, the appropriate encryption key and method are used to decrypt the contents (e.g., 128-bit plaintext is encrypted into 128-bit ciphertext). However, stream ciphers do not encrypt plaintext data in blocks, but rather increments of one bit (1-bit plaintext is encrypted into 1-bit ciphertext at a time).
Many current computer systems use symmetric encryption techniques to protect data and user privacy. Securing data in both secure communications and cloud storage requires the use of a symmetric cipher such as the Advanced Encryption Standard (AES).
Hardware implementations of AES can also be used instead of software ones. The AES 256, a specific form of the Advanced Encryption Standard with a key size of 256 bits, is commonly used in hardware-based symmetric encryption methods.
Contrary to popular belief, the blockchain of Bitcoin does not employ encryption. Digital signatures are generated without encryption using a specific algorithm known as Elliptic Curve Digital Signature Algorithm (ECDSA).
Elliptic-curve cryptography (ECC) is the foundation of the ECDSA, and it can be used for a variety of purposes, such as encryption, digital signatures, and pseudo-random generators. However, the ECDSA itself cannot be used to encrypt any data at all.
One of the advantages of using symmetric algorithms is that they can be encrypted and decrypted fast. Logistics are also a benefit because symmetric systems use less computer power than asymmetric systems. Symmetric encryption's level of security can be raised simply by using longer keys. A brute force assault on a symmetric key becomes increasingly more complex with each additional bit added to the length of the key.
Symmetric encryption has many advantages, but it has one big drawback: the difficulty of sending the encryption and decryption keys. These keys can be intercepted by malevolent third parties if shared over an unencrypted connection. Data encrypted with a specific symmetric key might be rendered insecure if it is obtained by an uninvited party. Many web protocols utilize a combination of symmetric and to address this issue. Transport Layer Security (TLS) is one of the most well-known examples of a hybrid system. In addition, it is important to emphasize that all methods of computer encryption are susceptible to security breaches because of poor implementation. Despite the fact that a brute force assault is mathematically impossible with a long enough key, programming flaws frequently generate vulnerabilities that allow for cyber attacks to proceed.
Modern computer systems encrypt data using symmetric encryption, one of the two most common ways. There is another type of public key cryptography, known as asymmetric encryption. Asymmetric systems require two keys instead of the one used by symmetric schemes, which is the fundamental difference between the two. Public keys can be shared, whereas private keys must remain private (private key).
Symmetric and asymmetric encryption differ in many ways since they both utilize two keys instead of just one. The complexity and speed of asymmetric algorithms are both higher. In order to achieve the same level of security as shorter symmetric keys, the keys used in asymmetric encryption must be much longer because their public and private parts are mathematically connected.