xBlind: Clinical Trial Blinding

The Problem

Clinical trial blinding is a single-authority decision. One corrupt, coerced, or compromised administrator can break the blind for any subject, undermining the scientific validity of the entire trial and potentially endangering patients.

Double-blind trials depend on a single Interactive Response Technology (IRT) system maintaining treatment assignments. The IRT vendor, the sponsor's unblinded statistician, or a determined insider can access the complete randomization table. A single breach exposes all assignments.

The consequences are severe. Premature unblinding can bias clinical outcomes, trigger regulatory rejection of the trial, waste years of research and billions in investment, and in some cases endanger patient safety through biased treatment decisions.

The Old Way

The PRIVATE.ME Solution

xBlind splits treatment assignments into N shares using XorIDA and distributes them to independent custodians. No single custodian can reveal assignments. Unblinding requires K custodians to collaborate, with every request audit-logged.

At randomization, each subject's treatment assignment is split into N shares. Each share goes to a different independent custodian -- a separate organization with no relationship to the others. Unblinding requires K custodians to submit their shares simultaneously, with HMAC verification ensuring no share was tampered with.

Emergency unblinding is preserved. For patient safety, a designated quorum of custodians can unblind a single subject. The protocol is threshold-based: fast enough for medical emergencies, but requiring consensus that prevents unauthorized access.

The New Way

How It Works

Treatment assignments are split at randomization, distributed to independent custodians, and reconstructed only when a threshold quorum approves unblinding. Every step is audit-logged for regulatory compliance.

Use Cases

Integration

import { blindAssignment, requestUnblind } from '@private.me/trialguard';

// Blind a treatment assignment across 3 custodians (2-of-3)
const shares = await blindAssignment('SUBJ-0042', 'active', {
  n: 3,
  k: 2,
  custodians: ['cro', 'irb', 'dsmb'],
});

// Emergency unblinding — requires quorum approval
const result = await requestUnblind('SUBJ-0042', {
  reason: 'SAE — immediate treatment decision required',
  requestor: 'dr.smith@site-12.org',
});
if (result.ok) {
  // result.value.treatment — 'active' or 'placebo'
  // result.value.auditId — immutable audit log reference
}

Security Properties

Cryptographic Proof of Correctness

This ACI's computations can be cryptographically verified by xProve — so regulators, auditors, and counterparties can confirm results without re-running the computation or accessing the underlying data.

Ready to deploy xBlind?

Talk to Ren, our AI sales engineer, or book a live demo with our team.

Ship Proofs, Not Source

xBlind generates cryptographic proofs of correct execution without exposing proprietary algorithms. Verify integrity using zero-knowledge proofs — no source code required.

Use Cases