Pith Number

pith:PHLOFSA2

pith:2026:PHLOFSA2SUTRDQLZEYUNKTSTGN

not attested not anchored not stored refs resolved

BIDO: A Biometric Identity Online Authentication Framework

Aditya Mithra, Sibi Chakkaravarthy S, Srinivas Kankanala

BIDO generates ECDSA keys on demand from a live face scan salted with a memorized secret to achieve AAL2 authentication without storing any biometric templates or PII.

arxiv:2605.16908 v1 · 2026-05-16 · cs.ET · cs.CR · cs.CV

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\usepackage{pith}
\pithnumber{PHLOFSA2SUTRDQLZEYUNKTSTGN}

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Record completeness

1 Bitcoin timestamp

2 Internet Archive

3 Author claim open · sign in to claim

4 Citations open

5 Replications open

✓ Portable graph bundle live · download bundle · merged state

The bundle contains the canonical record plus signed events. A mirror can host it anywhere and recompute the same current state with the deterministic merge algorithm.

Claims

C1strongest claim

BIDO achieves Authenticator Assurance Level 2 (AAL2) per NIST SP 800-63B without storing long-lived biometric templates, facial images, or any PII by deriving ECDSA key material deterministically from a live biometric measurement salted with a user-defined memorized secret at every authentication event.

C2weakest assumption

The multi-stage pipeline (Dlib landmark extraction, affine alignment, frontality gating, Euclidean distance quantization with q=8, inter-session drift stabilization, and majority-voting SHA-256 binding) produces a Verification Seed stable enough across sessions and devices to keep cryptographic FAR at 0.03% and FRR at 0.90% while remaining non-discoverable; the abstract provides no explicit mechanism or proof for the drift stabilization step.

C3one line summary

BIDO derives transient ECDSA keys from live facial biometrics salted with a memorized secret to produce non-resident WebAuthn credentials, achieving 99.51% verification accuracy on LFW without storing templates or PII.

References

29 extracted · 29 resolved · 1 Pith anchors

[1] FIDO2: Web Authentication Specification, 2019

[2] FIDO UAF Architectural Overview, 2017

[3] FIDO Alliance, “FIDO U2F Overview,” FIDO Alliance Specification v1.2, 2017. [Online]. Available: https://fidoalliance. org/specs/fido-u2f-v1.2-ps-20170411/fido-u2f-overview-v1.2-ps-20170411.html 2017

[4] On enabling secure applications through off-line biometric identification, 1998

[5] A fuzzy commitment scheme, 1999

Formal links

1 machine-checked theorem link

Receipt and verification

First computed	2026-05-20T00:03:29.566034Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

79d6e2c81a952711c1792628d54e53334a533d1c90ff7fc53dd97df37531615f

Aliases

arxiv: 2605.16908 · arxiv_version: 2605.16908v1 · doi: 10.48550/arxiv.2605.16908 · pith_short_12: PHLOFSA2SUTR · pith_short_16: PHLOFSA2SUTRDQLZ · pith_short_8: PHLOFSA2

Agent API

Resolver JSON Graph JSON Events JSON Schema Signing key

Verify this Pith Number yourself

curl -sH 'Accept: application/ld+json' https://pith.science/pith/PHLOFSA2SUTRDQLZEYUNKTSTGN \
  | jq -c '.canonical_record' \
  | python3 -c "import sys,json,hashlib; b=json.dumps(json.loads(sys.stdin.read()), sort_keys=True, separators=(',',':'), ensure_ascii=False).encode(); print(hashlib.sha256(b).hexdigest())"
# expect: 79d6e2c81a952711c1792628d54e53334a533d1c90ff7fc53dd97df37531615f

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "4f6f393c6d47c7dc46797ef9e101cae98476028c6c683924b1c7a735c16fe45a",
    "cross_cats_sorted": [
      "cs.CR",
      "cs.CV"
    ],
    "license": "http://creativecommons.org/licenses/by-nc-nd/4.0/",
    "primary_cat": "cs.ET",
    "submitted_at": "2026-05-16T09:49:10Z",
    "title_canon_sha256": "5a123f3fb0143ec0df2dbc879e315c6f8e37bf19f87cefed2211ee1e30ad548e"
  },
  "schema_version": "1.0",
  "source": {
    "id": "2605.16908",
    "kind": "arxiv",
    "version": 1
  }
}