fix(polynonce): reject unsupported degree parameter

[oritwoen]

PolynonceAttack::new(degree) accepted any value, but the elimination polynomial math is hardcoded for linear nonce relationships (degree=1). Setting --degree 2 would loosen the detection filter without actually implementing quadratic recovery, so the tool would report vulnerabilities it can't exploit.

Constructor now panics on degree != 1, and the CLI validates before construction with a proper error message.

Closes #20

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Configuration used: Organization UI

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📥 Commits

Reviewing files that changed from the base of the PR and between 4197b9b and cf0b08a.

📒 Files selected for processing (2)

• src/attack/polynonce.rs
• src/main.rs

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[cubic-dev-ai]

1 issue found across 2 files

Confidence score: 3/5

• There is a concrete user-facing regression risk in src/attack/polynonce.rs: a public constructor now panics on invalid input, which can abort downstream applications instead of returning a recoverable error.
• Given the issue’s medium severity (6/10) and high confidence (9/10), this is more than a minor cleanup concern and adds meaningful merge risk.
• This is likely fixable before release by restoring error-based validation for public API misuse, which would make the change safer for library consumers.
• Pay close attention to src/attack/polynonce.rs - public constructor input handling currently converts caller mistakes into panics.

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="src/attack/polynonce.rs">

<violation number="1" location="src/attack/polynonce.rs:18">
P2: This public constructor now panics on invalid input. That is fine for a private invariant, but here it turns a caller mistake into a process abort for library users instead of a normal error.</violation>
</file>

Architecture diagram

sequenceDiagram
    participant User as User / CLI
    participant Main as Main::run()
    participant Attack as PolynonceAttack

    User->>Main: Execute "polynonce" attack
    
    Note over Main,Attack: Validation Boundary
    
    alt NEW: degree != 1
        Main-->>User: NEW: anyhow::bail! (Error message)
    else degree == 1 (Supported)
        Main->>Attack: NEW: new(degree)
        Note right of Attack: CHANGED: Constructor now<br/>asserts degree == 1
        Attack->>Attack: NEW: assert!(degree == 1)
        
        Main->>Attack: detect(signatures)
        Attack-->>Main: List of vulnerabilities
        Main-->>User: Report results
    end

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[cubic-dev-ai]

P2: This public constructor now panics on invalid input. That is fine for a private invariant, but here it turns a caller mistake into a process abort for library users instead of a normal error.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At src/attack/polynonce.rs, line 18:

<comment>This public constructor now panics on invalid input. That is fine for a private invariant, but here it turns a caller mistake into a process abort for library users instead of a normal error.</comment>

<file context>
@@ -15,6 +15,10 @@ pub struct PolynonceAttack {
 
 impl PolynonceAttack {
     pub fn new(degree: usize) -> Self {
+        assert!(
+            degree == 1,
+            "only linear polynonce (degree=1) is implemented, got degree={degree}"
</file context>