Identity#
Identity Overview#
Identities are a low-level construct that provide the foundation for user-facing functionality on the platform. An identity is a public key (or set of public keys) recorded on the platform chain that can be used to prove ownership of data. Please see the Identity DIP for additional information.
Identities consist of three components that are described in further detail in the following sections:
Field |
Type |
Description |
---|---|---|
protocolVersion |
integer |
The protocol version |
id |
array of bytes |
The identity id (32 bytes) |
publicKeys |
array of keys |
Public key(s) associated with the identity |
balance |
integer |
Credit balance associated with the identity |
revision |
integer |
Identity update revision |
Each identity must comply with this JSON-Schema definition established in rs-dpp:
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"properties": {
"protocolVersion": {
"type": "integer",
"$comment": "Maximum is the latest protocol version"
},
"id": {
"type": "array",
"byteArray": true,
"minItems": 32,
"maxItems": 32,
"contentMediaType": "application/x.dash.dpp.identifier"
},
"publicKeys": {
"type": "array",
"minItems": 1,
"maxItems": 32,
"uniqueItems": true
},
"balance": {
"type": "integer",
"minimum": 0
},
"revision": {
"type": "integer",
"minimum": 0,
"description": "Identity update revision"
}
},
"required": [
"protocolVersion",
"id",
"publicKeys",
"balance",
"revision"
]
}
Example Identity
{
"protocolVersion":1,
"id":"6YfP6tT9AK8HPVXMK7CQrhpc8VMg7frjEnXinSPvUmZC",
"publicKeys":[
{
"id":0,
"type":0,
"purpose":0,
"securityLevel":0,
"data":"AkWRfl3DJiyyy6YPUDQnNx5KERRnR8CoTiFUvfdaYSDS",
"readOnly":false
}
],
"balance":0,
"revision":0
}
Identity id#
The identity id
is calculated by Base58 encoding the double sha256 hash of the outpoint used to fund the identity creation.
id = base58(sha256(sha256(<identity create funding output>)))
Note: The identity id
uses the Dash Platform specific application/x.dash.dpp.identifier
content media type. For additional information, please refer to the js-dpp PR 252 that introduced it and identifier.rs.
Identity publicKeys#
The identity publicKeys
array stores information regarding each public key associated with the identity. Multiple identities may use the same public key.
Note: Since v0.23, each identity must have at least two public keys: a primary key (security level 0
) that is only used when updating the identity and an additional one (security level 2
) used to sign state transitions.
Each item in the publicKeys
array consists of an object containing:
Field |
Type |
Description |
---|---|---|
id |
integer |
The key id (all public keys must be unique) |
type |
integer |
Type of key (default: 0 - ECDSA) |
data |
array of bytes |
Public key (0 - ECDSA: 33 bytes, 1 - BLS: 48 bytes, 2 - ECDSA Hash160: 20 bytes, 3 - BIP13 Hash160: 20 bytes) |
purpose |
integer |
Public key purpose (0 - Authentication, 1 - Encryption, 2 - Decryption, 3 - Withdraw) |
securityLevel |
integer |
Public key security level (0 - Master, 1 - Critical, 2 - High, 3 - Medium) |
readonly |
boolean |
Identity public key can’t be modified with |
disabledAt |
integer |
Timestamp indicating that the key was disabled at a specified time |
Keys for some purposes must meet certain security level criteria as detailed below:
Key Purpose |
Allowed Security Level(s) |
---|---|
Authentication |
Any security level |
Encryption |
Medium |
Decryption |
Medium |
Withdraw |
Critical |
Each identity public key must comply with this JSON-Schema definition established in rs-dpp:
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"properties": {
"id": {
"type": "integer",
"minimum": 0,
"description": "Public key ID",
"$comment": "Must be unique for the identity. It can’t be changed after adding a key. Included when signing state transitions to indicate which identity key was used to sign."
},
"type": {
"type": "integer",
"enum": [
0,
1,
2,
3
],
"description": "Public key type. 0 - ECDSA Secp256k1, 1 - BLS 12-381, 2 - ECDSA Secp256k1 Hash160, 3 - BIP 13 Hash160",
"$comment": "It can't be changed after adding a key"
},
"purpose": {
"type": "integer",
"enum": [
0,
1,
2,
3
],
"description": "Public key purpose. 0 - Authentication, 1 - Encryption, 2 - Decryption, 3 - Withdraw",
"$comment": "It can't be changed after adding a key"
},
"securityLevel": {
"type": "integer",
"enum": [
0,
1,
2,
3
],
"description": "Public key security level. 0 - Master, 1 - Critical, 2 - High, 3 - Medium",
"$comment": "It can't be changed after adding a key"
},
"data": true,
"readOnly": {
"type": "boolean",
"description": "Read only",
"$comment": "Identity public key can't be modified with readOnly set to true. It can’t be changed after adding a key"
},
"disabledAt": {
"type": "integer",
"description": "Timestamp indicating that the key was disabled at a specified time",
"minimum": 0
}
},
"allOf": [
{
"if": {
"properties": {
"type": {
"const": 0
}
}
},
"then": {
"properties": {
"data": {
"type": "array",
"byteArray": true,
"minItems": 33,
"maxItems": 33,
"description": "Raw ECDSA public key",
"$comment": "It must be a valid key of the specified type and unique for the identity. It can’t be changed after adding a key"
}
}
}
},
{
"if": {
"properties": {
"type": {
"const": 1
}
}
},
"then": {
"properties": {
"data": {
"type": "array",
"byteArray": true,
"minItems": 48,
"maxItems": 48,
"description": "Raw BLS public key",
"$comment": "It must be a valid key of the specified type and unique for the identity. It can’t be changed after adding a key"
}
}
}
},
{
"if": {
"properties": {
"type": {
"const": 2
}
}
},
"then": {
"properties": {
"data": {
"type": "array",
"byteArray": true,
"minItems": 20,
"maxItems": 20,
"description": "ECDSA Secp256k1 public key Hash160",
"$comment": "It must be a valid key hash of the specified type and unique for the identity. It can’t be changed after adding a key"
}
}
}
},
{
"if": {
"properties": {
"type": {
"const": 3
}
}
},
"then": {
"properties": {
"data": {
"type": "array",
"byteArray": true,
"minItems": 20,
"maxItems": 20,
"description": "BIP13 script public key",
"$comment": "It must be a valid script hash of the specified type and unique for the identity"
}
}
}
}
],
"required": [
"id",
"type",
"data",
"purpose",
"securityLevel"
],
"additionalProperties": false
}
Public Key id
#
Each public key in an identity’s publicKeys
array must be assigned a unique index number (id
).
Public Key type
#
The type
field indicates the algorithm used to derive the key.
Type |
Description |
---|---|
0 |
ECDSA Secp256k1 (default) |
1 |
BLS 12-381 |
2 |
ECDSA Secp256k1 Hash160 |
3 |
BIP13 pay-to-script-hash public key |
Public Key data
#
The data
field contains the compressed public key.
Public Key purpose
#
The purpose
field describes which operations are supported by the key. Please refer to DIP11 - Identities for additional information regarding this.
Type |
Description |
---|---|
0 |
Authentication |
1 |
Encryption |
2 |
Decryption |
3 |
Withdraw |
Public Key securityLevel
#
The securityLevel
field indicates how securely the key should be stored by clients. Please refer to DIP11 - Identities for additional information regarding this.
Level |
Description |
Security Practice |
---|---|---|
0 |
Master |
Should always require a user to authenticate when signing a transition. Can only be used to update an identity. |
1 |
Critical |
Should always require a user to authenticate when signing a transition |
2 |
High |
Should be available as long as the user has authenticated at least once during a session. Typically used to sign state transitions, but cannot be used for identity update transitions. |
3 |
Medium |
Should not require user authentication but must require access to the client device |
Public Key readOnly
#
The readOnly
field indicates that the public key can’t be modified if it is set to true
. The
value of this field cannot be changed after adding the key.
Public Key disabledAt
#
The disabledAt
field indicates that the key has been disabled. Its value equals the timestamp when the key was disabled.
Identity balance#
Each identity has a balance of credits established by value locked via a layer 1 lock transaction. This credit balance is used to pay the fees associated with state transitions.
Identity State Transition Details#
There are three identity-related state transitions: identity create, identity topup, and identity update. Details are provided in this section including information about asset locking and signing required for these state transitions.
Identity Creation#
Identities are created on the platform by submitting the identity information in an identity create state transition.
Field |
Type |
Description |
---|---|---|
protocolVersion |
integer |
The protocol version (currently |
type |
integer |
State transition type ( |
assetLockProof |
object |
Asset lock proof object proving the layer 1 locking transaction exists and is locked |
publicKeys |
array of keys |
Public key(s) associated with the identity |
signature |
array of bytes |
Signature of state transition data by the single-use key from the asset lock (65 bytes) |
Each identity must comply with this JSON-Schema definition established in rs-dpp:
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"properties": {
"protocolVersion": {
"type": "integer",
"$comment": "Maximum is the latest protocol version"
},
"type": {
"type": "integer",
"const": 2
},
"assetLockProof": {
"type": "object"
},
"publicKeys": {
"type": "array",
"minItems": 1,
"maxItems": 10,
"uniqueItems": true
},
"signature": {
"type": "array",
"byteArray": true,
"minItems": 65,
"maxItems": 65,
"description": "Signature made by AssetLock one time ECDSA key"
}
},
"additionalProperties": false,
"required": [
"protocolVersion",
"type",
"assetLockProof",
"publicKeys",
"signature"
]
}
Example State Transition
{
"protocolVersion":1,
"type":2,
"signature":"IBTTgge+/VDa/9+n2q3pb4tAqZYI48AX8X3H/uedRLH5dN8Ekh/sxRRQQS9LaOPwZSCVED6XIYD+vravF2dhYOE=",
"assetLockProof":{
"type":0,
"instantLock":"AQHDHQdekbFZJOQFEe1FnRjoDemL/oPF/v9IME/qphjt5gEAAAB/OlZB9p8vPzPE55MlegR7nwhXRpZC4d5sYnOIypNgzfdDRsW01v8UtlRoORokjoDJ9hA/XFMK65iYTrQ8AAAAGI4q8GxtK9LHOT1JipnIfwiiv8zW+C/sbokbMhi/BsEl51dpoeBQEUAYWT7KRiJ4Atx49zIrqsKvmU1mJQza0Y1YbBSS/b/IPO8StX04bItPpDuTp6zlh/G7YOGzlEoe",
"transaction":"0300000001c31d075e91b15924e40511ed459d18e80de98bfe83c5feff48304feaa618ede6010000006b483045022100dd0e4a6c25b1c7ed9aec2c93133f6de27b4c695a062f21f0aed1a2999fccf01c0220384aaf84cd5fd1c741fd1739f5c026a492abbfc18cfde296c6d90e98304f2f76012102fb9e87840f7e0a9b01f955d8eb4d1d2a52b32c9c43c751d7a348482c514ad222ffffffff021027000000000000166a14ea15af58c614b050a3b2e6bcc131fe0e7de37b9801710815000000001976a9140ccc680f945e964f7665f57c0108cba5ca77ed1388ac00000000",
"outputIndex":0
},
"publicKeys":[
{
"id":0,
"type":0,
"purpose":0,
"securityLevel":0,
"data":"AkWRfl3DJiyyy6YPUDQnNx5KERRnR8CoTiFUvfdaYSDS",
"readOnly":false
}
]
}
Identity TopUp#
Identity credit balances are increased by submitting the topup information in an identity topup state transition.
Field |
Type |
Description |
---|---|---|
protocolVersion |
integer |
The protocol version (currently |
type |
integer |
State transition type ( |
assetLockProof |
object |
Asset lock proof object proving the layer 1 locking transaction exists and is locked |
identityId |
array of bytes |
An Identity ID for the identity receiving the topup (can be any identity) (32 bytes) |
signature |
array of bytes |
Signature of state transition data by the single-use key from the asset lock (65 bytes) |
Each identity must comply with this JSON-Schema definition established in rs-dpp:
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"properties": {
"protocolVersion": {
"type": "integer",
"$comment": "Maximum is the latest protocol version"
},
"type": {
"type": "integer",
"const": 3
},
"assetLockProof": {
"type": "object"
},
"identityId": {
"type": "array",
"byteArray": true,
"minItems": 32,
"maxItems": 32,
"contentMediaType": "application/x.dash.dpp.identifier"
},
"signature": {
"type": "array",
"byteArray": true,
"minItems": 65,
"maxItems": 65,
"description": "Signature made by AssetLock one time ECDSA key"
}
},
"additionalProperties": false,
"required": [
"protocolVersion",
"type",
"assetLockProof",
"identityId",
"signature"
]
}
Example State Transition
{
"protocolVersion":1,
"type":3,
"signature":"IEqOV4DsbVa+nPipva0UrT0z0ZwubwgP9UdlpwBwXbFSWb7Mxkwqzv1HoEDICJ8GtmUSVjp4Hr2x0cVWe7+yUGc=",
"identityId":"6YfP6tT9AK8HPVXMK7CQrhpc8VMg7frjEnXinSPvUmZC",
"assetLockProof":{
"type":0,
"instantLock":"AQF/OlZB9p8vPzPE55MlegR7nwhXRpZC4d5sYnOIypNgzQEAAAAm8edm9p8URNEE9PBo0lEzZ2s9nf4u1SV0MaZyB0JTRasiXu8QtTmfqZWjI3qVtOpUhGPu6r/2fV+0Ffi3AAAAhA77E0aScf+5PTYzgV5WR6VJ/EnjvXyAMmAcu222JyvA7M+5OoCzVF/IQs2IWaPOFsRl1n5C+dMxdvrxhpVLT8QfZJSl19wzybWrHbGRaHDw4iWHvfYdwyXN+vP8UwDz",
"transaction":"03000000017f3a5641f69f2f3f33c4e793257a047b9f0857469642e1de6c627388ca9360cd010000006b483045022100d8c383b15a3738d13b029605d242f041bea874cb4d0def1303ca7cdf76092bf102201b1d401ae9e8cdc5efc061249d2a967960dadce53c66e34d249c42049b48b26701210335b684aa510a9b54a3a4f79283e64482a323190045c239fae5ecb0450c78f965ffffffff02e803000000000000166a14f5383f51784bc4a27e2040bdd6cd9aae7fe6814d31690815000000001976a9144a0511ec3362b35983d0a101f0572dd26abce2ee88ac00000000",
"outputIndex":0
}
}
Identity Update#
Identities are updated on the platform by submitting the identity information in an identity update state transition. This state transition requires either a set of one or more new public keys to add to the identity or a list of existing keys to disable.
Field |
Type |
Description |
---|---|---|
protocolVersion |
integer |
The protocol version (currently |
type |
integer |
State transition type ( |
identityId |
array of bytes |
The identity id (32 bytes) |
signature |
array of bytes |
Signature of state transition data (65 bytes) |
revision |
integer |
Identity update revision |
publicKeysDisabledAt |
integer |
(Optional) Timestamp when keys were disabled. Required if |
addPublicKeys |
array of public keys |
(Optional) Array of up to 10 new public keys to add to the identity. Required if adding keys. |
disablePublicKeys |
array of integers |
(Optional) Array of up to 10 existing identity public key ID(s) to disable for the identity. Required if disabling keys. |
signaturePublicKeyId |
integer |
The ID of public key used to sign the state transition |
Each identity must comply with this JSON-Schema definition established in rs-dpp:
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"properties": {
"protocolVersion": {
"type": "integer",
"$comment": "Maximum is the latest protocol version"
},
"type": {
"type": "integer",
"const": 5
},
"identityId": {
"type": "array",
"byteArray": true,
"minItems": 32,
"maxItems": 32,
"contentMediaType": "application/x.dash.dpp.identifier"
},
"signature": {
"type": "array",
"byteArray": true,
"minItems": 65,
"maxItems": 96
},
"revision": {
"type": "integer",
"minimum": 0,
"description": "Identity update revision"
},
"publicKeysDisabledAt": {
"type": "integer",
"minimum": 0
},
"addPublicKeys": {
"type": "array",
"minItems": 1,
"maxItems": 10,
"uniqueItems": true
},
"disablePublicKeys": {
"type": "array",
"minItems": 1,
"maxItems": 10,
"uniqueItems": true,
"items": {
"type": "integer",
"minimum": 0
}
},
"signaturePublicKeyId": {
"type": "integer",
"minimum": 0
}
},
"dependentRequired" : {
"disablePublicKeys": ["publicKeysDisabledAt"],
"publicKeysDisabledAt": ["disablePublicKeys"]
},
"anyOf": [
{
"type": "object",
"required": ["addPublicKeys"],
"properties": {
"addPublicKeys": true
}
},
{
"type": "object",
"required": ["disablePublicKeys"],
"properties": {
"disablePublicKeys": true
}
}
],
"additionalProperties": false,
"required": [
"protocolVersion",
"type",
"identityId",
"signature",
"revision",
"signaturePublicKeyId"
]
}
Asset Lock#
The identity create and identity topup state transitions both include an asset lock proof object. This object references the layer 1 lock transaction and includes proof that the transaction is locked.
Currently there are two types of asset lock proofs: InstantSend and ChainLock. Transactions almost always receive InstantSend locks, so the InstantSend asset lock proof is the predominate type.
InstantSend Asset Lock Proof#
The InstantSend asset lock proof is used for transactions that have received an InstantSend lock.
Field |
Type |
Description |
---|---|---|
type |
integer |
The asset lock proof type ( |
instantLock |
array of bytes |
The InstantSend lock ( |
transaction |
array of bytes |
The asset lock transaction |
outputIndex |
integer |
Index of the transaction output to be used |
Asset locks using an InstantSend lock as proof must comply with this JSON-Schema definition established in rs-dpp:
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"properties": {
"type": {
"type": "integer",
"const": 0
},
"instantLock": {
"type": "array",
"byteArray": true,
"minItems": 165,
"maxItems": 100000
},
"transaction": {
"type": "array",
"byteArray": true,
"minItems": 1,
"maxItems": 100000
},
"outputIndex": {
"type": "integer",
"minimum": 0
}
},
"additionalProperties": false,
"required": [
"type",
"instantLock",
"transaction",
"outputIndex"
]
}
ChainLock Asset Lock Proof#
The ChainLock asset lock proof is used for transactions that have note received an InstantSend lock, but have been included in a block that has received a ChainLock.
Field |
Type |
Description |
---|---|---|
type |
array of bytes |
The type of asset lock proof ( |
coreChainLockedHeight |
integer |
Height of the ChainLocked Core block containing the transaction |
outPoint |
object |
The outpoint being used as the asset lock |
Asset locks using a ChainLock as proof must comply with this JSON-Schema definition established in rs-dpp:
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"properties": {
"type": {
"type": "integer",
"const": 1
},
"coreChainLockedHeight": {
"type": "integer",
"minimum": 1,
"maximum": 4294967295
},
"outPoint": {
"type": "array",
"byteArray": true,
"minItems": 36,
"maxItems": 36
}
},
"additionalProperties": false,
"required": [
"type",
"coreChainLockedHeight",
"outPoint"
]
}
Identity State Transition Signing#
Note: The identity create and topup state transition signatures are unique in that they must be signed by the private key used in the layer 1 locking transaction. All other state transitions will be signed by a private key of the identity submitting them.
The process to sign an identity create state transition consists of the following steps:
Canonical CBOR encode the state transition data - this include all ST fields except the
signature
Sign the encoded data with private key associated with a lock transaction public key
Set the state transition
signature
to the value of the signature created in the previous step