Carr Digital LLC · Charlotte, North Carolina · est. 2026
Carr Digital is an independent software studio. It builds and operates Etergis, a digital continuity platform, and publishes measured research on migrating real systems to post-quantum cryptography. Small on purpose. Careful by trade.
Product · iOS, Android, and web
An end-to-end encrypted digital continuity platform. Store passwords, documents, and final instructions; if you become unreachable, the people you trust receive exactly what they need, automatically. Zero-knowledge by design, with a hybrid post-quantum envelope protecting stored secrets.
Book · ebook, 236 pages
Migrating TLS, PKI, and application crypto with evidence you can reproduce. Every number measured on stock OpenSSL, every claim labeled verified, reported, or proposed. Published 2026.
Research · free companion
Migration evidence for the NIST post-quantum standards, measured on stock OpenSSL rather than estimated from vendor decks: handshakes, certificate chains, envelope cryptography, and what the byte counts actually do to production systems.
Tools · no accounts, no tracking
The measurements, made usable: check what the post-quantum migration does to any public domain's certificate chain, work out your own handshake budget, or decode an X.509 certificate byte by byte without it leaving your browser.
A dead man's switch told its owner the delivery had gone out, during the window in which he could still have stopped it. Nothing had been sent. The backend was right the whole time, and the screen could have caused the event it was falsely reporting.
I minted a real Merkle Tree Certificate with one of the draft authors' own tooling and measured 87 bytes, then 727 bytes in a batch of a million. The more useful finding is that the failure I captured, a verifier refusing a certificate because it had fallen behind, was designed out of the specification fourteen months before I ran it.
Swap each embedded SCT signature for SLH-DSA-128s, the conservative hash-based choice for a long-lived log key, and leaf-only ML-DSA migration projects past the initial congestion window for 99.7% of 8,151 measured sites. The overflow is a corollary of 2022 arithmetic. The per-site distribution is what's new.
Carr Digital is founded and run by Danny B. Carr, Jr., a security engineer whose day work is enterprise public key infrastructure: issuing, monitoring, renewing, and revoking certificates, and automating the toil that follows. He has taught the subject as well as practiced it, in a university cybersecurity bootcamp and as a supervisory police instructor over a federal police academy he wrote the curriculum for. Before all of it he spent two decades in law enforcement and public safety, where he saw firsthand what families lose when important information dies with its owner. That experience is why Etergis exists.
He holds the CompTIA Security+, CySA+, and CASP certifications. Everything published here is personal work, built on personal time and personal equipment; views are his alone.
For anything about Etergis, the research, or the studio: carrdigitalllc@gmail.com. Etergis product support lives at etergis.com.