Public by design

A DID entry is a public notice board. Anyone can read it.

That leads to three plain rules.

1. No personal details. Do not put your name, birthday, ID numbers or address in a DID entry or in the document it links to. xrpl.org says a DID document should hold only two kinds of things: ways to verify you, such as public keys, and service points. The private facts stay with the issuer who checked them.

2. Your keys are your identity. Whoever holds your account's keys controls your DID. They can point it at a different document. If your keys leak, your DID is no longer yours. Guard them the way you guard your funds.

3. A DID is a claim, not proof. Making a DID costs a small reserve and a few seconds. A scammer can make one that names a famous project. Do not trust a DID because of what it says. Trust it when an issuer you already trust has vouched for it, and you have checked that the issuer did.

One worry is common and mostly wrong. People think that anyone can edit a document stored on IPFS. They cannot edit yours. On IPFS, a file's address comes from its content. Change the file and the address changes. Your DID still points at the original.

Others can copy your document. They cannot make your DID point at their copy without your keys.

From xrpl.org's privacy and security notes:

• Control. Whoever controls the account's private keys controls the DID and the reference to the document it resolves to.
• Content. Any content can go in a DID document. Limit it to verification methods and service points. DIDs on the XRPL are publicly available, so leave out personal information.
• Anchoring. Any entity can copy a DID document anchored with an account's DIDDocument or URI field. It cannot change the document unless it controls the private key that created the DID entry. Content addressing on IPFS means edited content has a different address.

No validation. The ledger does not check URI, DIDDocument or Data for validity. A resolver has to parse and validate whatever it retrieves. A malformed or misleading entry is still a successful DIDSet.

Updates. DIDSet overwrites fields in place, and DIDDelete removes the entry. Each DID entry records PreviousTxnID and PreviousTxnLgrSeq, the last transaction that changed it.

Where attestations live.

The on-ledger Credentials feature identifies the subject by an XRP Ledger address, not a URL. Its docs say credentials stored in the ledger can also authorize off-ledger activities, especially in association with a decentralized identifier. A credential's URI field can link to a W3C-formatted verifiable credential.

A verifier resolves the DID to its document, then uses the credential to verify authenticity. For an on-ledger credential, it also confirms the entry exists, was accepted and has not expired.

Related: Credentials, Collecting safely, Scams and signing.