What Is Ciphertext?
Ciphertext consists of a string of randomised characters that are the encrypted version of a text. It contains the same information as a message in plaintext, but is unreadable by a human or computer without a decryption algorithm. Ciphertext is commonly applied to protect the original message from the loss of sensitive information.
Examples of Ciphers
- Block ciphers: A block cipher encrypts data in blocks using a cryptographic key and algorithm to produce a ciphertext.
- Substitution ciphers: Substitution ciphers, as the name suggests, substitute the characters in a plaintext with other characters from the same set, depending on the key. For instance, A can be substituted with B, and C can be substituted with D.
- Transposition ciphers: Contrary to substitution ciphers, transposition ciphers maintain the same characters, but rearrange their order using an algorithm. For example, the phrase ‘a simple example’ can be transposed to ‘ELPMAXE ELPMIS A’.
- Private key cryptography: The same secret key is used to encrypt and decrypt a message in private key cryptography, also known as ‘symmetric key algorithm’.
- Public key cryptography: In comparison with private key cryptography, public key cryptography uses two keys — one for encryption, and another for decryption. The public key is used to encrypt plaintext into ciphertext, and the private key is used to decrypt the ciphertext into plaintext.