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Showing 1–30 of 204 reference entries

Physics · Information · MeasurementScientific records

Build an inspectable physics record, test and revise a bounded cart model, preserve processing history, and plan findable data with appropriate sharing conditions.

MethodMathematics & logic · InformationClassical propositions and connectives

Classical logic combines truth-valued propositions using defined connectives.

DefinitionMathematics & logic · InformationSets, membership and basic operations

A set specifies membership without counting duplicate listings.

DefinitionMathematics & logic · InformationFunctions, domain and codomain

A function assigns exactly one output to each input in its domain.

DefinitionMathematics & logic · InformationMathematical induction

A base case and general successor step establish a predicate on all nonnegative integers.

MethodMathematics & logic · InformationComplex numbers

A complex number has real coordinates a and b and an imaginary unit satisfying i²=−1.

DefinitionMathematics & logic · Information · PhysicsLinear maps and matrix representation

A linear map preserves linear combinations and has a matrix once bases are chosen.

DefinitionMathematics & logic · InformationProbability space and axioms

A probability assigns nonnegative, normalised, countably additive weights to events.

DefinitionMathematics & logic · InformationConditional probability and independence

Conditioning restricts attention to an event of positive probability.

DefinitionMathematics & logic · InformationExpected value of a discrete random variable

Expected value weights possible values by their probabilities.

DefinitionInformation · Mathematics & logicBits and unsigned binary encoding

A bit has two possible states; a fixed-width unsigned binary word encodes an integer.

DefinitionInformation · Mathematics & logicShannon entropy of a discrete distribution

Shannon entropy measures uncertainty in a specified probability distribution.

DefinitionInformationAlgorithm and decision procedure

An algorithm specifies effective steps; a decision procedure must terminate on every permitted input.

MethodInformation · Mathematics & logicUndecidability of the halting problem

No total algorithm decides halting for every program and input in a general computation model.

Mathematical statementInformation · Mathematics & logicAsymptotic upper bounds and big O

Big O bounds eventual growth up to a fixed constant factor.

DefinitionInformationFinite-alphabet mutual information

Mutual information measures statistical dependence in bits.

DefinitionInformationNear-lossless source coding threshold

Entropy bounds asymptotic compression for an iid source.

Mathematical statementInformationDiscrete memoryless channel capacity

Capacity is the maximal asymptotically reliable rate.

Mathematical statementInformationHamming distance and error correction

Separated codewords permit bounded symbol-error recovery.

Mathematical statementInformationInternet protocol layers

Protocol layers divide communication responsibilities.

DefinitionInformationTCP reliable byte-stream transport

TCP orders bytes and retransmits detected losses.

MethodInformationEncryption, hashes and message authentication

Cryptographic primitives serve distinct security properties.

DefinitionInformationPublic-key digital signatures

A signing key and a verification key have different roles.

DefinitionInformationComputable reductions and undecidability

Reduction direction determines which impossibility transfers.

Mathematical statementInformationDecision classes P and NP

Polynomial solving and polynomial verification differ.

DefinitionInformationNP-hardness and NP-completeness

NP-completeness combines verification and reduction hardness.

DefinitionInformationBounded-error randomized computation

Random choices permit a stated probability of error.

DefinitionInformationFinite graphs and trees

Graphs represent pairwise connections; trees impose acyclicity.

DefinitionInformationData-structure interfaces and operation costs

An interface defines operations; an implementation determines costs.

MethodInformationLoop invariants and total correctness

An invariant establishes correctness only with its proof obligations.

Method
DefinitionSource checked

Encryption, hashes and message authentication

Information

Cryptographic primitives serve distinct security properties.

Key knowledge

Encryption transforms plaintext into ciphertext for confidentiality. A cryptographic hash maps input to a fixed-size digest with computational resistance properties. A message authentication code uses a shared secret to check message authenticity and integrity.

Conditions and scope

  • A plain digest alone does not establish who produced a message.
  • Security depends on the algorithm, parameters, keys and threat model; none is an unconditional guarantee.
Sources · 3

References

Sources retain their recorded scope. A source link alone does not establish verification of every statement.

  1. National Institute of Standards and Technology (NIST)3 sources
    1. Glossary: EncryptionNISTReference guidecsrc.nist.govRead source
    2. Glossary: Cryptographic hash functionNISTReference guidecsrc.nist.govRead source
    3. Glossary: Message authentication codeNISTReference guidecsrc.nist.govRead source

Evidence and review

Attributed standard definitions of plaintext-to-ciphertext transformation and confidentiality. Fixed-length output, computational one-way and collision-resistance properties; glossary scope. Symmetric-key authentication/integrity mechanism, not encryption.

2026-10-10 · NIST's attributed glossary definitions; implementation recommendations excluded.

Related reference entries

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Showing 1–2 of 2 relationships

Scientific relationships · 2 / 2

The relationship type describes the connection. Its linked statements, sources and conditions define the scope.

  1. Related to
    Relationship sources · 1

    Linked statements

    • In an indistinguishability experiment, an efficient adversary selects equal-length messages and receives an encryption of one chosen by a hidden random bit. Chosen-plaintext security gives the permitted encryption oracle and requires negligible distinguishing advantage as the security parameter grows. It hides content subject to the game, not message length, access patterns or a compromised endpoint. Randomized encryption or correctly managed nonces prevent deterministic equality leakage in the appropriate model.

    The primitive must satisfy a declared attack model.

  2. Related to
    Relationship sources · 1

    Linked statements

    • Existential unforgeability under chosen-message attack requires that an efficient adversary with a tagging oracle cannot produce a valid tag for a new message with more than negligible probability. Strong unforgeability can additionally prohibit new valid tags on previously tagged messages. A MAC uses a shared secret and does not provide publicly verifiable attribution; replay protection requires a protocol freshness rule beyond the raw MAC game.

    Authentication has a different experiment from encryption.

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