docs: clarify 1-of-N auditor signature semantics (#1404)

Signed-off-by: Siddhi Khandelwal <siddhi.200727@gmail.com>

Author: sid200727

token/core/common/validator_auditing.go

@@ -20,6 +20,22 @@ var (
 )
 
 // AuditingSignaturesValidate validates the auditor signatures in the token request.
+//
+// Auditor Signature Model:
+//
+// The current implementation follows a 1-of-N auditor signature policy:
+//
+//   - If auditors are configured in the public parameters, at least one
+//     valid auditor signature must be present in the token request.
+//   - Multiple auditor public keys may be configured (e.g., during key rotation).
+//   - The validator verifies that each provided auditor signature corresponds
+//     to a configured auditor and that the signature is valid.
+//   - The validator does NOT enforce N-of-N semantics.
+//   - The validator does NOT enforce per-entity auditor checks.
+//   - All configured auditor public keys are treated as belonging to a
+//     single logical auditor entity.
+//
+// This behavior matches the semantics implemented by current token drivers.
 func AuditingSignaturesValidate[P driver.PublicParameters, T driver.Input, TA driver.TransferAction, IA driver.IssueAction, DS driver.Deserializer](c context.Context, ctx *Context[P, T, TA, IA, DS]) error {
 	if len(ctx.PP.Auditors()) == 0 {
 		// enforce no auditor signatures are attached
@@ -35,6 +51,11 @@ func AuditingSignaturesValidate[P driver.PublicParameters, T driver.Input, TA dr
 	}
 
 	auditors := ctx.PP.Auditors()
+
+	// Each provided auditor signature is independently verified.
+	// The presence of at least one valid signature is sufficient
+	// to satisfy the auditing requirement (1-of-N policy).
+
 	for _, auditorSignature := range ctx.TokenRequest.AuditorSignatures {
 		auditor := auditorSignature.Identity
 		// check that issuer of this issue action is authorized