The original readable message is known as plaintext, and its encrypted form is called ciphertext. Both contain the same underlying information. The difference is that ciphertext can typically only be read by someone who has the correct decryption mechanism, usually a secret value known as a cryptographic key.
Ciphers can also be classified by how they process data. A block cipher encrypts fixed-size groups of bits at a time, while a stream cipher encrypts data one bit or byte at a time. Modern standards such as the Advanced Encryption Standard (AES) are widely used block ciphers, and they generally replace older methods that are no longer considered secure.
Ciphers are not a recent invention. They were used to encode messages long before computers existed, dating back to at least 400 BC. A well-known example is the substitution cipher attributed to Julius Caesar, which replaced each letter in a message with the letter three places further along the alphabet. Using that method of shifting the alphabets down by 3, the word BINANCE would become ELQDQFH, a string that looks meaningless to anyone who does not know the shift value.
Understanding how ciphers work can give you a clearer picture of how cryptographic systems keep information confidential. While most users never interact with ciphers directly, these algorithms operate in the background of many secure applications, helping keep sensitive data harder for unauthorized parties to read.
The science of using mathematical theories and computation in order to encrypt and decrypt information.
Conversion of information or data into a secure code in order to prevent unauthorised access to the informa...
The act of reverting an encryption process so that unreadable data (ciphertext) can be converted into reada...