v1.0 MIT Spec frozen 2026 Zero deps

Memory for the next fifty years.

VeriCore is an append-only, hash-chained, locally-verifiable log for the knowledge, decisions, and rules you want to still have in 2076. No network. No blockchain. No vendor. Just a file and 700 lines of Python.

$ pip install vericore

Read the spec →

Most software is designed for the next five years. This one is designed for the next fifty.

Principles

Append-only

Entries are written once. To revoke, you append a revocation — the original never disappears.

Hash-chained

Every entry carries the BLAKE2b-128 digest of the previous. A single byte flip is detectable at the exact line.

Human-readable

One entry per line. Tab-separated. Base64-framed. Grep works. cat works. Future archaeologists work.

Zero dependencies

Pure Python standard library. No network calls. No crypto library. No package graph to rot in 2041.

Example session

$ vc init ~/mem.vc
initialized chain at ~/mem.vc (genesis: 0a4f...c91e)

$ vc add know "Sleep ≥ 7h improves decision quality." --src pubmed:2019-08
#1  know  0a4f→b812  +src pubmed:2019-08

$ vc add dec "Adopt 23:00 lights-out rule." --confidence 0.8
#2  dec   b812→3f09  confidence=0.80
   └─ rule fired: REQUIRE dec FOR know#1  ✓

$ vc verify
chain OK · 2 entries · head 3f09...a7b2

$ printf 'x' >> ~/mem.vc    # simulate tamper
$ vc verify
FAIL at line 3: prev-hash mismatch (expected 3f09..., got a142...)

Specification

A format, not a library.

The library is the reference implementation. The format is the commitment. vcn-v1.0 is 160 lines of prose and grammar, frozen against the golden vectors in the test suite. Anyone can reimplement it in any language and produce byte-identical output on the same inputs.

That is the point. In fifty years, Python may not exist. The file still will.

vcn-v1.0.md → Golden vectors →

┌──────────┐      ┌──────────┐      ┌──────────┐
│  entry 0 │━━━━>│  entry 1 │━━━━>│  entry 2 │
│  genesis │ h0  │   know   │ h1  │    dec   │
└──────────┘      └──────────┘      └──────────┘
     │                 │                 │
     │  h(payload)     │  h(prev+pl)     │  h(prev+pl)
     ▼                 ▼                 ▼
  0a4f...c91e       b812...dd04       3f09...a7b2
                                          │
                                          ▼
                                       HEAD ✓

Entry types

knowA fact or observation, optionally sourced.

decA decision, with a confidence in [0, 1].

ruleA .vs expression evaluated on every append.

linkA directed relation between two entries.

revokeA pointer marking an earlier entry invalid.

noteFreeform text. Unstructured but verified.

Six types. One file. A chain that will still verify long after the service you used last Tuesday has shut down.

Browse the source →