Use of Predictable Algorithm in Random Number Generator

The device uses an algorithm that is predictable and generates a pseudo-random number.


Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

Suppose a cryptographic function expects random value to be supplied for the crypto algorithm.

During the implementation phase, due to space constraint, a cryptographically secure random-number-generator could not be used, and instead of using a TRNG (True Random Number Generator), a LFSR (Linear Feedback Shift Register) is used to generate a random value. While an LFSR will provide a pseudo-random number, its entropy (measure of randomness) is insufficient for a cryptographic algorithm.

See Also

Comprehensive Categorization: Randomness

Weaknesses in this category are related to randomness.

Random Number Issues

Weaknesses in this category are related to a software system's random number generation.

Security Primitives and Cryptography Issues

Weaknesses in this category are related to hardware implementations of cryptographic protocols and other hardware-security primitives such as physical unclonable funct...

Comprehensive CWE Dictionary

This view (slice) covers all the elements in CWE.

Entries with Maintenance Notes

CWE entries in this view have maintenance notes. Maintenance notes are an indicator that an entry might change significantly in future versions. This view was created...

Weaknesses Introduced During Implementation

This view (slice) lists weaknesses that can be introduced during implementation.


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