Public Key Announcement
*Since DSNP version 1.3, public keys use [User Data](../UserData.md) operations.*A Public Key Announcement is a way to note a new cryptographic key that can be used in DSNP to secure and verify the authenticity of communications.
The most recently published key (if one exists) for a given key type should be treated as the active key of that key type.
Fields
| Field | Description | Data Type | Serialization | Parquet Type | Bloom Filter |
|---|---|---|---|---|---|
| announcementType | Announcement Type Enum (7) | enum | decimal | INT32 | no |
| fromId | id of the user creating the Announcement | 64 bit unsigned integer | decimal | UINT_64 | YES |
| keyType | Key Type Enum | enum | decimal | INT32 | YES |
| keyId | user-assigned identifier | 64 bit unsigned integer | decimal | UINT_64 | no |
| publicKey | public key in multikey format | variable length byte array | UTF-8 | BYTE_ARRAY | no |
Field Requirements
announcementType
- MUST be fixed to
7
fromId
- MUST be a DSNP User Id
keyType
- MUST be an allowed Key Type value
Allowed Key Types
| Value | Name | Allowed Algorithms (multicodec) | Purpose |
|---|---|---|---|
| 1 | keyAgreement | x25519-pub | A Curve25519 public key that can be used in key exchange protocols to generate a shared secret |
| 2 | assertionMethod | ed25519-pub | A public key that can be used for verifying digital signature proofs of verifiable credentials |
keyId
- A user-assigned 64-bit identifier for the key.
The user may assign a new keyId each time they announce a new key of a given keyType.
A keyId value is useful when invoking certain DSNP Operations in order to indicate which key was used to encrypt data.
It may also provide a hint to the user if they ever need to regenerate their private key (for example, many key derivation functions enable the use of a subkey identifier to deterministically create a subkey from a root key).
publicKey
- MUST be a public key of an allowed algorithm for
keyType, encoded inmultikeyformat
The multikey encoding of public keys is described in the draft did:key Method specification.
The byte encoding consists of a multicodec key identifier (as a varint) followed by the public key’s binary data in the codec’s described format.
If serializing the multicodec value as a string, base58btc encoding is recommended.
For example, the string z6LStiZsmxiK4odS4Sb6JmdRFuJ6e1SYP157gtiCyJKfrYha decodes as a Base58 string using the x25519-pub multicodec value with a 32-byte raw key of 0xfd3384e132ad02a56c78f45547ee40038dc79002b90d29ed90e08eee762ae715.