4. Identity
A node's ID is a name, not a position. It carries no meaning, and once a document is established it is never recomputed, reassigned or reused.
4.1 Letter-first base32#
To encode a SHA-256 digest d (32 bytes) as a letter-first ID of n characters:
- The first character is the letter at index
d[0] mod 22ofabcdefghjkmnpqrstvwxyz. - Read the bytes
d[1]tod[31]as one big-endian bit string. - Each further character is the Crockford character for the next five bits, from the most significant end.
Node IDs have seven characters, about 34.5 bits; derived record IDs have 13.
ids.jsonl in the vectors gives digests and their encodings.
4.2 Minting node IDs#
A node's ID is minted from SHA-256 of the canonical JSON of the array ["scienting-id/1", doc_key, kind, text_hash, occurrence], encoded with seven characters.
text_hash is the plain, never keyed, text hash of the node (5.1).
When a document is established, nodes are minted in document order. A node's occurrence starts at the number of earlier nodes with the same kind and text hash; while the resulting ID is already taken, the occurrence increases by one. So a fresh conversion of the same input mints the same IDs.
A node added later, by an insert or a split, starts at occurrence 0 and increases while the ID is taken by any live, retired or alias ID of the document.
Columns and figure-text items are not nodes, but they take IDs from the same rule and the same document-wide set, after the nodes:
a column with kind column and the text hash of its header cells' plain projections joined with U+0020;
a figure-text item with kind figure-text and the text hash of its text.
4.3 Permanence, retirement and aliases#
| Rule | Detail |
|---|---|
| Permanence | Once established, an ID never changes, and no other node ever takes it. |
| Retirement | A merge or a delete retires IDs (11). A merge records the surviving node as the successor; a delete records none. |
| Aliases | Legacy IDs, such as the b-p03-text-004 block IDs an earlier extract format used, are recorded as aliases of the node that now holds that text. |
| Labels | What people say, such as "Eq. 3" or "Table S1", is a label, never an ID. |
| Display paths | Tools may show a path such as §2.3 ¶4 s2; it is never stored or cited. |
4.4 ids.jsonl#
Each line is one entry.
| Property | Holds |
|---|---|
id | The retired node ID, or the alias. |
kind | retired or alias. |
successor | For a retirement, the successor's ID, or null for a deletion; for an alias, the live node it names. |
node_kind | For a retirement, the kind the node had. |
rev | For a retirement, the index of the correction that retired it. |
Aliases come first, sorted by ID; retirements follow, sorted by rev and then ID.
No ID is both live and in the table, every successor is live or itself in the table, and every alias names a live node.
4.5 Store-qualified names#
A document key qualified by its store, smithlab/cornell1995second, names a document anywhere, and an address with a store names a node anywhere (6.1).
4.6 Record IDs#
A record that is never edited takes its ID from its own content, as 13 letter-first characters of a hash:
| Record | Hash |
|---|---|
| Receipt, revocation, policy | The record hash: SHA-256 of the record without id and signature (8.4). |
| Correction | SHA-256 of the record without id. |
| Annotation | SHA-256 of the annotation without id, status, receipt and modified, as created. |
| Submission, digitization | SHA-256 of the record without id. |
A witness ID is the seven-character letter-first encoding of the witness's SHA-256 itself. Other records, such as layers and qa reports, MAY use any record ID unique in their store.