Android and iOS

Constant-time APIs for secret comparisons

Key lifecycles, signatures, encryption and application data.

Keys and cryptography1 min readEditorial methods

Comparison timing can reveal information about secret values. Suitable library APIs help reduce that exposure.

Evaluation approach

Use documented functions rather than custom loops and review input types and lengths.

Application example

A Python verifier can use an appropriate secure comparison API for MACs instead of ordinary string equality.

Limits and considerations

Constant-time comparison does not fix weak keys, missing verification or faulty authorization.

Is a network timing test enough?

Network noise can hide small differences. Correct library use is the foundation; a simple speed test does not prove side-channel resistance.

Checks and decisions

  • Choose the right API
  • Control input types
  • Review failures

Sources

The primary references above provide the technical basis. Example workflows and evaluation suggestions are this publication’s explanations, not independent test results for a particular product.