maskedSeed

A masked seed, in cryptographic practice, refers to a seed value that has been combined with a random mask to conceal the seed during computation or storage. The mask is typically a random bitstring, and common masking methods include exclusive OR (XOR) or additive masking. The purpose is to prevent an attacker from learning the true seed from intermediate values in a calculation or from exposed memory.

How it works. A secret seed s is paired with a fresh random mask m to produce a maskedSeed, for example by computing maskedSeed = s XOR m. The computation proceeds using maskedSeed while the mask m remains available only to authorized parts of the system. When the seed is needed for a cryptographic operation, the original seed can be recovered by unmasking, i.e., s = maskedSeed XOR m, in a controlled, secure context. The mask is typically regenerated frequently to ensure that no single mask reveals useful information.

Purpose and use. Masked seeds are used to reduce information leakage through side-channel sources such as power consumption, timing, or electromagnetic emanations. By operating on masked values, the relationship between secret data and observable signals is obscured, making certain attacks more difficult. Masked seeds can appear in hardware modules, secure enclaves, and implementations that require constant-time or leakage-resilient behavior.

Security considerations. The effectiveness of masked seeds depends on the secrecy and freshness of the mask, as well as correct unmasking procedures. Reuse of masks, improper unmasking, or poor random number generation can undermine security. Proper isolation of the unmasked seed and careful handling of masks are essential to avoid inadvertent disclosure.

See also: masking, side-channel attack, constant-time cryptography.