Encryption, Encoding and Hashing

Encryption, encoding, and hashing are all methods used to protect data, but they are used for different purposes and have different characteristics.

Table of Contents

Encryption

Encryption is the process of converting plaintext data into ciphertext so that it can only be read by someone with the decryption key. Encryption is used to protect sensitive data, such as credit card numbers or personal information, from unauthorized access. It is reversible, meaning that the original data can be recovered using the appropriate decryption key.

Different types of encryption

There are several different types of encryption, each with its own set of strengths and weaknesses. Some of the most common types of encryption include:

Symmetric encryption: This type of encryption uses the same key for both encryption and decryption. It is fast and efficient, but the key must be securely exchanged between parties before any data can be encrypted or decrypted. Advanced Encryption Standard (AES) is a symmetric encryption standard that is widely used to secure data. It uses a fixed block size of 128 bits and supports key sizes of 128, 192, and 256 bits.
Asymmetric encryption: This type of encryption uses a pair of keys, one for encryption and one for decryption. It is more secure than symmetric encryption, but it is slower and more resource-intensive. RSA is an asymmetric encryption algorithm that is widely used to secure data. It is used for digital signatures, software protection, and secure communications.
Block encryption: This type of encryption encrypts data in fixed-size blocks, typically 64 or 128 bits. It is commonly used in disk encryption and other applications where data must be encrypted in place.
Stream encryption: This type of encryption encrypts data one bit or byte at a time. It is commonly used in network communications and other applications where data must be encrypted in transit.

Encoding

Encoding is the process of converting data into a different format so that it can be transmitted or stored more efficiently. Encoding is not intended to protect data from unauthorized access, but to ensure that the data can be transmitted or stored without errors.

Different types of encoding

There are several different types of encoding, including:

Base64: This is a method of encoding binary data into ASCII text. It is commonly used to encode images, audio, and other types of multimedia in emails, web pages, and other text-based formats.
URL Encoding: This is a method of encoding special characters in URLs, it is used to ensure that URLs are valid and can be transmitted over the internet without any issues.
UTF-8: This is a variable-length character encoding for Unicode. It is designed to handle any character in the Unicode standard, yet it is backward-compatible with ASCII. It is widely used for the web and other applications.
UTF-16: This is a variable-length character encoding for Unicode. It uses two bytes (16 bits) per character, and it can handle any character in the Unicode standard. It is commonly used in Windows and other systems.
ASCII: This is a character encoding that assigns unique numbers to each character of the English alphabet, numerals, punctuation marks, and control characters.
EBCDIC: This is a character encoding that assigns unique numbers to each character of the English alphabet, numerals, punctuation marks, and control characters, mostly used in mainframe systems.
Binary: This is a method of encoding data in which each digit is represented by a combination of 0s and 1s.

Hashing

Hashing is the process of creating a fixed-length output, called a hash, from input data of any length. Hashing is used to verify the integrity of data. Hashes are one-way functions, meaning that the original data cannot be recovered from the hash. Common use cases include storing password hashes in databases or file integrity checking.

Different Hashing Functions

There are several different types of hashing functions, including:

MD5: This is a widely-used cryptographic hash function that produces a 128-bit hash value. It is fast and efficient, but it is now considered to be insecure due to known collisions.
SHA-1: This is a cryptographic hash function that produces a 160-bit hash value. It is similar to MD5, but it is considered to be more secure.
SHA-2: This is a set of cryptographic hash functions that includes SHA-224, SHA-256, SHA-384, and SHA-512. They are considered to be more secure than SHA-1, but they are also slower and require more resources.
SHA-3: This is a set of cryptographic hash functions that includes SHA3-224, SHA3-256, SHA3-384, and SHA3-512. It is considered to be more secure than SHA-2 and also designed to resist certain attacks on SHA-2.
BLAKE2: This is a cryptographic hash function that produces a fixed-length output, similar to MD5 and SHA-1. It is considered to be faster and more secure than these algorithms.
bcrypt: This is a password-hashing function designed to be slow and resource-intensive, making it more resistant to brute-force attacks.
Scrypt : This is a password-hashing function which is also designed to be slow and resource-intensive, making it more resistant to brute-force and dictionary attacks.

Hashing with Salt

Salting is a technique used in conjunction with hashing to enhance the security of hashed passwords. A salt is a random value that is generated and added to the input data before it is hashed. The salt is then stored along with the hash value, and is used to validate the input data when the same data is hashed again.

When a user enters a password, the same salt value is added to the password and the resulting value is hashed. The resulting hash value is then compared to the stored hash value. If the two values match, the password is considered to be correct.

Adding a salt to the data before hashing it helps to protect against dictionary and precomputed attacks. It makes it harder for an attacker to use pre-computed tables of hash values (rainbow tables) to find the plaintext value of the password. Because the salt is unique for each user, an attacker would have to create a separate rainbow table for each user, which can be infeasible.

It is important to note that the salt must be cryptographically secure, meaning it should be generated using a suitable random number generator and it should be stored securely. Also, the salt should be different for each user and for each password, otherwise the security of the system can be compromised.