Encryption security as an IND-CPA experiment
Research context
postgraduate concept · established · As of 2026-10-10
In an indistinguishability experiment, an efficient adversary selects equal-length messages and receives an encryption of one chosen by a hidden random bit.
Key knowledge
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.
Values and equations
Adv_guess(A)=|Pr[b_hat=b]−1/2|
- b
- Uniform hidden challenge bit
- b_hat
- Adversary's guess
- A
- Adversary with stated oracle and computational resources
Conditions and scope
- Specify secret/public-key game, number of queries, security parameter, nonce policy and allowed leakage.
- Equal-length challenge messages avoid trivially distinguishable length; confidentiality does not establish authenticity.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Author checked this English statement, displayed equation where present and stated hypotheses against these source locations: Encryption games chapters 2–3/9/12, authentication chapters 6–8, signatures chapter 13, reductions and identification/zero knowledge chapters 18–20. The check is bounded to the recorded claims; no complete proof reconstruction, software proof replay or universal literature completeness is claimed.
2026-10-10 · Author source-body/statement/equation/domain check, with graph associations scoped individually. Separate independent content/source/inventory review is required before branch closure.
Entry details
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- research-info-encryption-ind-cpa
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- Postgraduate & research reference