Before we dive deep into what encryption means we first need to learn about cipher text.
Ciphertext
The term "ciphertext" originates from the word "cipher," which means "code" or "secret message."
The ciphertext is the encoded or encrypted version of plaintext, which is the original, unencrypted message. The process of converting plaintext into ciphertext is known as encryption, and the process of converting ciphertext back into plaintext is known as decryption.
The use of ciphers to encrypt messages dates back to ancient civilizations. The use of ciphers for military and diplomatic purposes also has a long history, with famous examples including the Caesar Cipher used by Julius Caesar, and the Enigma Machine used by the German military during World War II.
About Caesar Cipher
The Caesar Cipher is a basic form of encryption named after Julius Caesar who used it for sending private messages. It works by replacing each letter of the message with a letter a certain number of spaces down the alphabet. For example, using a shift of 3, the letter "A" would become "D", "B" would become "E", and so on.
While easy to use, this type of encryption is also easy to crack, particularly when the shift is small. For example, a shift of 1 would mean "A" becomes "B", "B" becomes "C" and so on, making it simple for someone to analyze the encoded message and figure out the shift to decrypt it. Despite its simplicity, the Caesar Cipher was a crucial step in the development of more complex encryption methods. Today, it is mostly used as a learning tool to introduce the concepts of encryption and decryption to students of cryptography or as a basic example of substitution cipher.
About Enigma machine
During World War II, the German military used the Enigma machine for encrypting and decrypting messages. It was an electromechanical device that employed a series of rotors and reflectors for the substitution of letters in the messages, making it hard to decipher without the correct settings and key. The machine had a keyboard for inputting the message, and a lampboard for displaying the encoded message. Although it was considered highly secure at the time, it was successfully cracked by Polish and British codebreakers, which provided valuable information to the Allies. Nowadays, the Enigma machine and its encryption method are considered an important part of the history of cryptography and have influenced the development of more advanced encryption technologies. It is also widely studied as a case study in the field of cryptography and is a popular subject in popular culture.
With the advent of modern computers and the internet, the use of ciphers and encryption has become increasingly important for protecting sensitive information in our digital age. Today, ciphers and encryption algorithms are used in a wide variety of applications, such as secure communication, secure storage, and secure payment.
Encryption
Encryption is a method of protecting information by converting it from plain text into a coded or encrypted form, known as ciphertext. The process uses mathematical algorithms, called ciphers, to scramble the data in such a way that it can only be read by someone with the proper decryption key or password. This helps prevent unauthorized access or use of sensitive information, such as credit card numbers, personal data, and corporate secrets.
There are two main types of encryption: symmetric and asymmetric.
Symmetric encryption: Symmetric encryption uses the same key for both encryption and decryption. This key is kept secret and shared between the sender and the receiver. Examples of symmetric encryption algorithms include AES and Blowfish.
Asymmetric encryption: Asymmetric encryption, also known as public key encryption, uses a pair of keys, one for encryption and one for decryption. The encryption key is made public, while the decryption key is kept private. This allows for secure communication without the need for a shared secret key. Examples of asymmetric encryption algorithms include RSA and Elliptic Curve Cryptography.
Both symmetric and asymmetric encryption is used in various applications to protect sensitive information from unauthorized access or use. Depending on the use case, one may be preferred over the other or they can be used together to enhance security.
Encryption is widely used in various applications, including secure communication (e.g. email, instant messaging), secure storage (e.g. hard drives, cloud storage), and secure payment (e.g. online transactions). It is also used to protect personal data, such as passwords and credit card numbers, when transmitted over the internet.
Encryption has several advantages and disadvantages
Advantages:
Security: Encryption protects sensitive information from unauthorized access or use by converting it into a coded or encrypted form.
Confidentiality: Encryption ensures that only authorized parties can read the encrypted message, thereby maintaining the confidentiality of the information.
Authentication: Encryption can be used to authenticate the identity of the sender and the integrity of the message.
Compliance: Encryption is often used to comply with legal and regulatory requirements for protecting sensitive information.
Data protection: Encryption can help protect data both in transit and at rest.
Disadvantages:
Complexity: Encryption can be complex to implement and manage, especially for large organizations or those with multiple systems and devices.
Performance impact: Encryption can add some computational overhead, which can impact the performance of systems and devices.
Key management: Encryption requires the secure management of encryption keys, which can be challenging.
Not a guarantee of security: Encryption is not a guarantee of security, as it only protects against unauthorized access and not against weaknesses in the encryption algorithm or key management.
Cost: Encryption can add some costs, such as for hardware, software, and personnel.
It's important to note that encryption is only one aspect of security, and it should be used in conjunction with other security measures such as firewalls, intrusion detection, and access controls, to provide comprehensive security for systems and data.
Hashing
Hashing is the process of generating a fixed-length string of characters, known as a "hash" or "digest," from an input, or "message." The resulting hash will always be the same for the same input, but even a slight change in the input will result in a vastly different hash.
Hashing is commonly used in computer security to ensure the integrity of data, for example, in digital signatures, password storage, and data integrity checking.
One of the main uses of hashing is to store passwords securely. Instead of storing the plain-text password in a database, a hash of the password is stored. When the user enters their password, the system will hash the entered password and compare it with the stored hash. If they match, the user is authenticated.
There are several types of hashing algorithms, including:
MD5 (Message-Digest Algorithm 5): This is a widely-used hashing algorithm that produces a 128-bit hash. It is considered to be relatively fast, but it is also considered to be less secure than more recent algorithms.
SHA-1 (Secure Hash Algorithm 1): This is a 160-bit hash algorithm that is similar to MD5 but considered to be more secure. It is also widely-used, but it has been phased out in favor of more secure options.
SHA-2 (Secure Hash Algorithm 2): This is a family of hash algorithms that includes SHA-256, SHA-384, and SHA-512. These algorithms produce hash values that are 256, 384, or 512 bits in length, respectively. They are considered to be more secure than MD5 and SHA-1.
SHA-3 (Secure Hash Algorithm 3): This is a family of hash algorithms that includes SHA3-224, SHA3-256, SHA3-384, and SHA3-512. These algorithms are considered to be more secure than the SHA-2 family of algorithms.
BLAKE2: is a family of cryptographic hash functions that are faster than SHA-3 and provides a similar level of security
bcrypt: is a password-hashing function which is designed to be slow and computationally expensive, making it resistant to brute force attacks.
Argon2: is a password-hashing function that is designed to be resistant to both brute force attacks and side-channel attacks.
It's important to note that the selection of the hashing algorithm depends on the security needs, the level of security required, and the resources available (memory, CPU, etc.
It is important to note that hashing is not a form of encryption and it can't be reversed, meaning that you can't take the hash and get the original input. Also, it is theoretically possible to find two different inputs that produce the same hash (known as a collision), so it is not recommended to use hash functions alone for sensitive data.
Salting is a method used in combination with hashing to improve the security of stored passwords and other sensitive information. It works by adding a random string of characters, called a salt, to the original plaintext before it is hashed. The salt is then saved with the hashed password. When a user tries to log in, the salt is retrieved, added to the plaintext password they entered, and the resulting string is hashed. This new hash is then compared to the stored hash.
Salting protects against dictionary attacks, where an attacker precomputes the hash values of a large number of possible inputs (such as common words or phrases) and then compares them to the stored hash to find a match. By adding a unique and random salt to each password, the attacker would have to precompute the hash values for each possible salt and password combination, making the attack much more computationally expensive. It's important to remember that the salt must be unique and random for each password, otherwise, it would be ineffective, and it should be stored securely along with the hashed password.
Summary
Encryption and hashing are both techniques used to protect sensitive information, but they are used for different purposes and have some key differences:
Encryption:
Encryption is a technique used to protect the confidentiality of information by converting it into a coded or encrypted form that can only be read by someone with the correct decryption key.
Encryption is reversible, meaning that the original data can be recovered from the encrypted data with the correct key.
Encryption is commonly used for secure communication, such as in email and messaging apps, and for protecting data at rest, such as on hard drives and cloud storage.
Hashing:
Hashing is a technique used to ensure the integrity of information by generating a fixed-length string of characters, known as a "hash" or "digest," from an input, or "message."
Hashing is not reversible, meaning that the original data cannot be recovered from the hash.
Hashing is commonly used for password storage, data integrity checking, and for digital signatures.
In summary, encryption is used to protect data confidentiality and integrity, while hashing is mainly used to ensure data integrity and for password storage. Both encryption and hashing are important for providing security to the data, but they have different use cases and should be used accordingly.