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Vol. 1 · Ed. 2026
CyberGlossary
Entry № 832

Plaintext

What is Plaintext?

PlaintextReadable, unencrypted form of data that is the input to encryption and the output of correct decryption.


Plaintext is the original, human- or machine-readable representation of information before encryption is applied or after it has been correctly decrypted. In cryptographic protocols the term is used to distinguish data inside the trust boundary from ciphertext that may safely traverse hostile channels. Plaintext also commonly refers to passwords or secrets stored without hashing or encryption, which is a major security failing. Defensive practices include encrypting plaintext at rest with strong AEAD ciphers, encrypting in transit with TLS, redacting plaintext from logs and error messages, and never sending sensitive plaintext in URLs or referrer headers.

Examples

  1. 01

    A password value passed in JSON before TLS encrypts the request.

  2. 02

    Logs that accidentally print a credit card number in plaintext.

Frequently asked questions

What is Plaintext?

Readable, unencrypted form of data that is the input to encryption and the output of correct decryption. It belongs to the Cryptography category of cybersecurity.

What does Plaintext mean?

Readable, unencrypted form of data that is the input to encryption and the output of correct decryption.

How does Plaintext work?

Plaintext is the original, human- or machine-readable representation of information before encryption is applied or after it has been correctly decrypted. In cryptographic protocols the term is used to distinguish data inside the trust boundary from ciphertext that may safely traverse hostile channels. Plaintext also commonly refers to passwords or secrets stored without hashing or encryption, which is a major security failing. Defensive practices include encrypting plaintext at rest with strong AEAD ciphers, encrypting in transit with TLS, redacting plaintext from logs and error messages, and never sending sensitive plaintext in URLs or referrer headers.

How do you defend against Plaintext?

Defences for Plaintext typically combine technical controls and operational practices, as detailed in the full definition above.

Related terms