Architecture / AIGIS resources

LLM field-level security has to happen before the prompt exists.

Field-level security for LLMs is different from field-level security in a screen or report. If a model sees a redacted field name, it can still reason about the field's existence. AIGIS removes the field before the prompt is built.

Executive read

The short version, before the deep dive.

LLM field-level security must control both values and structure.

Masking hides values but can reveal field names and relationships.

Field stripping removes inaccessible fields before the model sees context.

The same control must apply to summaries, answers, write proposals, and tool calls.

Analysis

What matters

Why redaction is weaker for language models

A traditional app can show a redacted value and still be safe enough for the user's workflow. A language model is different because it can reason about the existence of the redacted field.

If the prompt contains Salary__c: [redacted], the model has learned that salary exists, that it is relevant, and that it may relate to the user's question.

Field stripping changes the model's world

AIGIS removes inaccessible fields before the prompt is assembled. The model is not asked to ignore forbidden data because the forbidden data never arrives.

That makes the LLM's reasoning boundary match the user's permission boundary.

Permissions need to cover writes too

A write proposal can leak just as much as a read. If the AI suggests changing a field the user cannot edit, the proposal itself has crossed the governance line.

AIGIS checks write permissions before proposal and again when the human confirms the write.

Comparison

Scan the decision table.

Requirement
Masking
Field stripping
Hide value
Yes
Yes
Hide field existence
No
Yes
Reduce inference
Partial
Strong
Minimize prompt context
No
Yes
Best fit for LLMs
Limited
Yes