Plaintext

As explained in Real-World Cryptography

Cleartext, or plaintext, is data represented in its original readable form rather than in encrypted or otherwise transformed form.

Plaintext is data in its original readable form before encryption or another transformation. It may be text, an image, a video, or anything representable as bits. Encryption transforms plaintext into ciphertext; decryption restores it. section 4.1

Plaintext appears at several points in a cryptographic process:

• Alice starts with a message such as “hello,” encrypts the plaintext with a secret key, and sends ciphertext to Bob. section 4.1
• AES accepts exactly 128 bits of plaintext and produces 128 bits of ciphertext; its reversible mapping depends on the key. section 4.2.2
• A server that stores passwords in cleartext exposes the original passwords if its database is breached. section 11.2

Readable before protection

The word “hello” is plaintext while Alice is preparing it. After encryption it becomes ciphertext that should look random to observers; Bob decrypts it back into the original plaintext. section 4.1

Figure 4.1 Alice (top right) encrypts the plaintext hello with the key 0x8866... (an abbreviated hexadecimal). Then Alice sends the ciphertext to Bob. Bob (bottom right) decrypts the received ciphertext by using the same key and a decryption algorithm.

Follow the message path from plaintext to ciphertext and back again using the same symmetric key. section 4.1

How Real-World Cryptography covers it

How deep it goes

Defines plaintext, traces its encryption and recovery, and relates it to AES block size without detailing cipher implementation.

Examples

Uses “hello,” arbitrary bit-representable media, AES’s 128-bit input, and passwords stored in cleartext.

What you can do after

Evaluate whether data is exposed before encryption and distinguish plaintext from ciphertext during basic cryptographic workflows.

How it connects

Connects plaintext with ciphertext, encryption, decryption, symmetric keys, AES, password storage, and password hashing.

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Related concepts

• encryptionproduced by · Encryption is the cryptographic transformation of readable data into ciphertext to conceal its contents, reversible through decryption with appropriate information.
• maskcontrasts with · Masking is the selective representation, concealment, inclusion, exclusion, or restriction of parts of data or a system according to specified criteria.
• output formatcontrasts with · An output format is a specified structure or representation in which a result is returned or produced.

This explainer was generated by Manning's knowledge graph from the text of Real-World Cryptography. The section links point to the parts of the book it draws on.