CIP-0095

CIP	Title	Category	Status	Authors	Implementors	Discussions	Created	License
95	Web-Wallet Bridge - Conway ledger era	Wallets	Active	Ryan Williams <[email protected]>	Eternl <https://eternl.io/> GeroWallet <https://gerowallet.io> Lace <https://www.lace.io/> Mesh <https://meshjs.dev/> mLabs <https://mlabs.city/> NuFi <https://nu.fi/> Ryan Williams <[email protected]> Typhon <https://typhonwallet.io/> Lido Nation <https://www.lidonation.com/> Vespr <https://vespr.xyz/> Yoroi <https://yoroi-wallet.com/>	https://github.com/cardano-foundation/cips/pulls/509 https://discord.com/channels/826816523368005654/1101547251903504474/1101548279277309983 https://discord.com/channels/826816523368005654/1143258005354328156/1143272934966837309	2022-02-24	CC-BY-4.0

Abstract

This document describes an interface between webpage/web-based stacks and Cardano wallets. This specification defines the API of the javascript object that needs to be injected into web applications.

These definitions extend CIP-30 | Cardano dApp-Wallet Web Bridge to provide support for CIP-1694 | A First Step Towards On-Chain Decentralized Governance focussed web-based stacks. Here we aim to support the requirements of Ada holders and DReps in the Conway Ledger era, this specification is based on the Conway Ledger Era Specification.

For the many contributors to this proposal, see Acknowledgements.

Motivation: why is this CIP necessary?

CIP-1694 introduces many new concepts, entities and actors to Cardano; describing their implementation at the ledger level. This creates the need for new tooling with respect to governance. For the average ecosystem participant, the details should be abstracted away, enabling them to leverage the new ledger features more effectively. This specification allows for creation of web-based tools for the utilization of CIP-1694's governance features.

Whilst CIP-30 facilitated the launch of dApp development on Cardano, it's functionality is limited in scope. It was written well before the emergence of the Conway Ledger Era and thus lacks the required methods to support full user interaction. We believe that expecting existing CIP-30 implementors to upgrade implementations is unfeasible, thus we must extend it's functionality with this API.

This proposal enables Ada holders, and DReps to engage web-based tooling through wallets. Thus the primary stakeholders for this proposal are tool developers and wallet providers. Here we aim to outline all endpoints needed to be exposed to web based tools to support all the needs Ada holders and DReps to engage with CIP-1694's governance design.

Specification

We define the following section as an extension to the specification described within CIP-30. Although currently CIP-30 acts as the defacto Cardano dApp-wallet connector, this specification could be applied to similar standards.

Note This specification will evolve as the proposed ledger governance model is finalized.

Data Types

CIP-30 Inherited Data Types

From CIP-30's Data Types we inherit:

Address

A string representing an address in either bech32 format, or hex-encoded bytes. All return types containing Address must return the hex-encoded bytes format, but must accept either format for inputs.

Bytes

A hex-encoded string of the corresponding bytes.

cbor<T>

A hex-encoded string representing CBOR corresponding to T defined via CDDL either inside of the Shelley Multi-asset binary spec or, if not present there, from the CIP-0008 signing spec. This representation was chosen when possible as it is consistent across the Cardano ecosystem and widely used by other tools, such as cardano-serialization-lib, which has support to encode every type in the binary spec as CBOR bytes.

DataSignature

type DataSignature = {|
  signature: cbor<COSE_Sign1>,
  key: cbor<COSE_Key>,
|};

Extension

An extension is an object with a single field "cip" that describe a CIP number extending the API (as a plain integer, without padding). For example:

{ "cip": 30 }

CIP-95 Data Types

PubDRepKey

type PubDRepKey = string;

A hex-encoded string representing 32 byte Ed25519 DRep public key, as described in CIP-0105 | Conway Era Key Chains for HD Wallets.

DRepID

type DRepID = string;

A hex-encoded string representing a registered DRep's ID which is a Blake2b-224 hash digest of the above mentioned 32 byte Ed25519 public key, as described in CIP-1694 Registered DReps.

PubStakeKey

type PubStakeKey = string;

A hex-encoded string representing 32 byte Ed25519 public key used as a staking credential.

Error Types

For the methods described in Governance Extension API, we inherit APIError, DataSignError and TxSignError from CIP-30's Error Types.

Note We choose to reword some descriptions from CIP-30, to improve clarity.

APIError

We repurpose this error type from CIP-30, extending it's functionality. We extend the Refused error code to also include the case of the extension no longer being enabled.

APIErrorCode {
	InvalidRequest: -1,
	InternalError: -2,
	Refused: -3,
	AccountChange: -4,
}
type APIError {
	code: APIErrorCode,
	info: string
}

• InvalidRequest - Inputs do not conform to this specification or are otherwise invalid.
• InternalError - An internal wallet error occurred during execution of this API call.
• Refused - The request was refused due to lack of access - e.g. wallet disconnects or extension is no longer enabled.
• AccountChange - The account has changed. The client application should call wallet.enable() to reestablish connection to the new account. The wallet should not ask for confirmation as the user was the one who initiated the account change in the first place.

TxSignError

We repurpose this error type from CIP-30, extending it's functionality. We extend the ProofGeneration error code to also include cases where DRep secret key is not available. We also add one new error code DeprecatedCertificate.

TxSignErrorCode = {
  ProofGeneration: 1,
  UserDeclined: 2,
  DeprecatedCertificate: 3,
};
type TxSignError = {
  code: TxSignErrorCode;
  info: String;
};

• ProofGeneration - User has accepted the transaction sign, but the wallet was unable to sign the transaction. This is because the wallet does have some of the private keys required.
• UserDeclined - User declined to sign the transaction.
• DeprecatedCertificate - Returned regardless of user consent if the transaction contains a deprecated certificate.

DataSignError

We repurpose this error type from CIP-30, extending it's functionality. We extend the ProofGeneration error code to also include cases where DRep secret key is not available.

DataSignErrorCode {
	ProofGeneration: 1,
	AddressNotPK: 2,
	UserDeclined: 3,
}
type DataSignError = {
	code: DataSignErrorCode,
	info: String
}

• ProofGeneration - Wallet could not sign the data; because the wallet does not have the secret key to the associated with the address or DRep ID.
• AddressNotPK - Address was not a P2PK address and thus had no SK associated with it.
• UserDeclined - User declined to sign the data.

Governance Extension API

These are the CIP-95 methods that should be returned as part of the API object, namespaced by cip95 without any leading zeros.

For example: api.cip95.getPubDRepKey()

To access these functionalities a client application must present this CIP-95 extension object, as part of the extensions object passed at enable time:

cardano.{wallet-name}.enable({ extensions: [{ cip : 95 }]})

api.cip95.getPubDRepKey(): Promise<PubDRepKey>

The connected wallet account provides the account's public DRep Key, derivation as described in CIP-0105.

These are used by the client to identify the user's on-chain CIP-1694 interactions, i.e. if a user has registered to be a DRep.

Returns

The wallet account's public DRep Key.

Errors

Error Type	Error Code	Return Condition
APIError	InvalidRequest	Returned if a input parameter is passed.
APIError	InternalError	Returned if there is a generic internal error occurred during execution of this API call.
APIError	Refused	Returned if there is a refusal, could be wallet disconnection or extension is revoked.
APIError	AccountChange	Returned if wallet has changed account, meaning connection should be reestablished.

api.getRegisteredPubStakeKeys(): Promise<PubStakeKey[]>

The connected wallet account's registered public stake keys. These keys may or may not control any Ada, but they must all have been registered via a stake key registration certificate. This includes keys which the wallet knows are in the process of being registered (already included in a pending stake key registration certificate).

If none of the wallets stake keys are registered then an empty array is returned.

These keys can then be used by the client to identify the user's on-chain CIP-1694 interactions, and also create vote delegation certificates which can be signed via .signTx().

Returns

An array of the connected user's registered public stake keys.

Errors

Error Type	Error Code	Return Condition
APIError	InvalidRequest	Returned if a input parameter is passed.
APIError	InternalError	Returned if there is a generic internal error occurred during execution of this API call.
APIError	Refused	Returned if there is a refusal, could be wallet disconnection or extension is revoked.
APIError	AccountChange	Returned if wallet has changed account, meaning connection should be reestablished.

api.cip95.getUnregisteredPubStakeKeys(): Promise<PubStakeKey[]>

The connected wallet account's unregistered public stake keys. These keys may or may not control any Ada. This includes keys which the wallet knows are in the process of becoming unregistered (already included in a pending stake key unregistration certificate).

If the wallet does not know the registration status of it's stake keys then it should return them as part of this call. If all of the wallets stake keys are registered then an empty array is returned.

These keys can then be used by the client to identify the user's on-chain CIP-1694 interactions, i.e if a user has delegated to a DRep.

Returns

An array of the connected user's unregistered stake keys.

Errors

Error Type	Error Code	Return Condition
APIError	InvalidRequest	Returned if a input parameter is passed.
APIError	InternalError	Returned if there is a generic internal error occurred during execution of this API call.
APIError	Refused	Returned if there is a refusal, could be wallet disconnection or extension is revoked.
APIError	AccountChange	Returned if wallet has changed account, meaning connection should be reestablished.

api.signTx(tx: cbor<transaction>, partialSign: bool = false): Promise<cbor<transaction_witness_set>>

This endpoint requests the wallet to inspect and provide appropriate witnesses for a supplied transaction. The wallet should articulate this request from client application in a explicit and highly informative way.

Here we extend the capabilities of CIP-30's .signTx(). To allow signatures with drep_credential and recognition of Conway ledger era transaction fields and certificates.

Expected Inspection Support

As read from cardano-ledger Conway draft specification.

Supporting wallets should be able to recognize and inspect all the following certificates and data contained in transaction bodies, in any combination.

Index	Supported Pre-Conway Certificates
0	stake_registration
1	stake_deregistration
2	stake_delegation
3	pool_registration
4	pool_retirement

Index	Supported Conway Certificates
5	reg_cert
6	unreg_cert
7	vote_deleg_cert
8	stake_vote_deleg_cert
9	stake_reg_deleg_cert
10	vote_reg_deleg_cert
11	stake_vote_reg_deleg_cert
12	auth_committee_hot_cert
13	resign_committee_cold_cert
14	reg_drep_cert
15	unreg_drep_cert
16	update_drep_cert

Transaction Index	Supported Conway Transaction Field Data
19	voting_procedure
20	proposal_procedure
21	coin (current treasury value)
22	positive_coin (new donation)

All other potential transaction field inclusions 0-18, should be able to be recognized by supporting wallets.

Unsupported Inspection

In the Conway ledger era two certificate types are deprecated genesis_key_delegation and move_instantaneous_rewards_cert. If the wallet receives a transaction containing a deprecated certificate it should return a TxSignError with an error code of DeprecatedCertificate.

Index	Unsupported Pre-Conway Certificates
5	genesis_key_delegation
6	move_instantaneous_rewards_cert

Expected Witness Support

Although constitutional committee certificates and stake pool certificates should be able to be recognized they should not be able to be correctly witnessed by wallets following this API. Wallet's should only support witnesses using payment, stake and DRep keys.

Returns

The portions of the witness set that were signed as a result of this call are returned. This encourages client apps to verify the contents returned by this endpoint before building the final transaction.

Errors

Error Type	Error Code	partialSign	Return Condition
APIError	InvalidRequest	true or false	Returned if an erroneous parameter is passed, wrong type or too many etc.
APIError	InternalError	true or false	Returned if there is a generic internal error occurred during execution of this API call.
APIError	Refused	true or false	Returned if there is a refusal, could be wallet disconnection or the extension is revoked.
APIError	AccountChange	true or false	Returned if wallet has changed account, meaning connection should be reestablished.
TxSignError	ProofGeneration	false	Returned if user has accepted transaction to sign, but the wallet is unable to sign because it does not have the required key(s).
TxSignError	UserDeclined	true or false	Returned if user has declined to sign the transaction.
TxSignError	DeprecatedCertificate	true or false	Returned regardless of user consent if the transaction contains a deprecated certificate.

If partialSign is true, the wallet only tries to sign what it can. If partialSign is false and the wallet could not sign the entire transaction, TxSignError shall be returned with the ProofGeneration code.

api.cip95.signData(addr: Address | DRepID, payload: Bytes): Promise<DataSignature>

Errors: APIError, DataSignError

This endpoint requests the wallet to inspect and provide a DataSignature for the supplied data. The wallet should articulate this request from client application in a explicit and highly informative way.

Here we extend the capabilities of CIP-30's .signData(). To allow for signatures using DRep keys.

This endpoint utilizes the CIP-0008 | Message Signing for standardization/safety reasons. It allows the client app to request the user to sign a payload conforming to said spec.

Supported Credentials

Here we define how each key is identified by an Address in relation to CIP-0019 | Cardano Addresses, these are all Shelley key-hash-based addresses.

We allow for DRepID to be passed in the addr field to signal signature using the associated DRep key.

To construct an address for DRep Key, the client application should construct a type 6 address. Using an appropriate Network Tag and a hash of a public DRep Key.

Key	Identifying addr
Payment Key	Address types: 0, 2, 4, 6.
Stake Key	Address type: 14.
DRep Key	DRepID

These keys will be used to sign the COSE_Sign1's Sig_structure with the following headers set:

• alg (1) - must be set to EdDSA (-8)
• kid (4) - Optional, if present must be set to the same value as in the COSE_key specified below. It is recommended to be set to the same value as in the "address" header.
• "address" - must be set to the raw binary bytes of the address as per the binary spec, without the CBOR binary wrapper tag

The payload is not hashed and no external_aad is used.

Returns

The return shall be a DataSignature with signature set to the hex-encoded CBOR bytes of the COSE_Sign1 object specified above and key shall be the hex-encoded CBOR bytes of a COSE_Key structure with the following headers set:

• kty (1) - must be set to OKP (1).
• kid (2) - Optional, if present must be set to the same value as in the COSE_Sign1 specified above.
• alg (3) - must be set to EdDSA (-8).
• crv (-1) - must be set to Ed25519 (6).
• x (-2) - must be set to the public key bytes of the key used to sign the Sig_structure.

Errors

Error Type	Error Code	Return Condition
APIError	InvalidRequest	Returned if a input parameter is passed.
APIError	InternalError	Returned if there is a generic internal error occurred during execution of this API call.
APIError	Refused	Returned if there is a refusal, could be wallet disconnection or extension is revoked.
APIError	AccountChange	Returned if wallet has changed account, meaning connection should be reestablished.
DataSignError	ProofGeneration	Returned if user has accepted to sign, but wallet could not sign the data; because the wallet does not have the required keys.
DataSignError	AddressNotPK	Returned if Address was not a P2PK address and thus had no SK associated with it.
DataSignError	UserDeclined	Returned if the user declined to sign the data.

Versioning

Whilst this CIP is in it's unmerged proposed state, it remains very fluid and substantial changes can happen, so we would advise against any implementation. Once more feedback is received, maturing this design, implementations can safely emerge, alongside this proposal's merger into the CIPs repository. Once merged only small necessary changes should be made, ideally in backwards compatible fashion.

This, in tandem with, maturing implementations should move this proposal to an active state where only small backwards compatible changes can be made. If any large changes are needed once active then a new proposal should be made to replace this one. This we believe aligns with the (new) extendibility design of CIP-0030.

Examples of Flows

Connection and Login

This describes a potential flow of connection between CIP-95 compatible client application and wallet, then a subsequent login.

1. Connection: User indicates to the client their intent to connect, causing client offer a list of supported wallets, user selects their desired wallet. The client will then invoke .{wallet-name}.enable({extensions: [{ "cip": 95 }]}) from the shared cardano namespace, ensuring to pass in the CIP-95 extension object.
2. Wallet Confirmation: The wallet indicates through its UI the clients intent to connect, the user should then grant permission.
3. Share Credentials: The client invokes both .getRegisteredPubStakeKeys() and .getPubDRepKey(), causing the connected wallet to share relevant credentials.
4. Chain Lookup: The client uses a chain indexer to work out the governance state of the provided credentials. The results of the lookup are then shown to the user, acting as a login.

Vote Delegation

Assume a DRep Aggregator and Delegation specialized client app, that aggregates DRep metadata from DRep registration certificates and renders this metadata to show prospective delegators. Assume that connection to a users wallet has already been made via cardano.{wallet-name}.enable({extensions: [{ cip: 95 }]}).

1. Choose DRep: User browses DReps and selects one which align's with their values to delegate too. It is up to the client application to choose and manage which stake key should be used for this delegation, this could be with or without user input.
2. Construct Delegation: The client application uses CIP-30 endpoints to query the wallet's UTxO set and payment address. A DRep delegation certificate (vote_deleg_cert) is constructed by the app using the chosen DRep's ID and wallet's stake credential. A transaction is constructed to send 1 ADA to the wallet's payment address with the certificate included in the transaction body.
3. Inspect and Sign: The app passes the transaction to the wallet via .signTx(). The wallet inspects the content of the transaction, informing the user of the client app's intension. If the user confirms that they are willing to sign, the wallet returns the appropriate witnesses, of payment key and stake key.
4. Submit: The app will add the provided witnesses into the transaction body and then pass the witnessed transaction back to the wallet for submission via .submitTx().
5. Feedback to user: The wallet returns the submitted transaction's hash, the app can use this to track the status of the transaction on-chain and provide feedback to the user.

DRep Registration

Assume a DRep Registration specialized client app, that allows people to register as a DRep. Assume that connection to a users wallet has already been made via cardano.{wallet-name}.enable({extensions: [{ cip: 95 }]}) and that the user is not a registered DRep.

1. User Indicates Intent: User indicates to the client that they wish to register as a DRep. The client asks the user to provide metadata anchor, this is bundled with DRepID the client generates from the wallet's public DRep Key provided via .getPubDRepKey().
2. Construct Registration: The client application uses CIP-30 endpoints to query the wallet's UTxO set and payment address. A DRep registration certificate (reg_drep_cert) is constructed by the app using the wallet's DRep ID and the provided metadata anchor. A transaction is constructed to send 1 ADA to the wallet's payment address with the certificate included in the transaction body.
3. Inspect and sign: The app passes the transaction to the wallet via .signTx(). The wallet inspects the content of the transaction, informing the user of the client app's intension. If the user confirms that they are happy to sign, the wallet returns the appropriate witnesses, of payment key and DRep key (drep_credential).
4. Submit: The app will add the provided witnesses into the transaction body and then pass the witnessed transaction back to the wallet for submission via .submitTx().
5. Feedback to user: The wallet returns the submitted transaction's hash, the app can use this to track the status of the transaction on-chain and provide feedback to the user.

Rationale: how does this CIP achieve its goals?

The principle aim for this design is to reduce the complexity for wallet implementors whilst maintaining backwards compatibility with CIP-30 implementations. This is motivated by the necessity for users to be able to interact with the age of Voltaire promptly, by keeping the wallet's providers ask small we aim to reduce implementation time.

This design aims to make the tracking of a user's governance state an optional endeavour for wallet providers. This is achieved by placing the responsibility on clients to track a user's governance state, i.e. if a wallet user is a DRep, what DRep a wallet user has delegated to, etc.

Despite only defining the minimal set of endpoints required, we do not wish to discourage the creation of subsequent CIPs with a wider range of governance functionality. Nor does this specification aim to discourage wallet providers from fully integrating governance features, side-stepping the necessity for this API (matching how staking is achieved).

Why Web-based Stacks?

Web-based stacks, with wallet connectivity, are a familiar place for users to be able to interact with Cardano. These tools lower the technical bar to engage with the ecosystem. Thus we believe encouraging further adoption of this approach is beneficial.

The primary alternative approach is for wallet providers to integrate this functionality fully inside of wallet software, matching how staking is often implemented. We deem this approach as preferable from a security standpoint, we would encourage wallet providers to pursue this. But we understand that this adds significant overhead to wallet designs, so we offer this API as an alternative.

Why DReps and Ada Holders?

This proposal only caters to two types of governance actor described in CIP-1694; Ada holders and DReps, this decision was three fold. Primarily, this is to allow these groups to utilize a web-based client to participate in Cardano's governance. These groups are likely less comfortable utilizing command-line interfaces than other groups, thus making alternatives from them is a priority. Secondly, the other types of actor (constitutional committee members and SPOs) are identified by different credentials than Ada holders and DReps, making their integration in this specification more complex. These alternative credentials are unlikely to be stored within standard wallet software which may interface with this API. Thirdly, Ada holders and DReps likely represent the majority of participants thus we aim to cast a wide net with this specification.

Unsupported Items

In this specification we have placed explicit boundaries on what should not be supported with .signTx(). Those being not witnessing stake pool or constitutional committee, certificates and not inspecting genesis key delegation or MIR certificates.

From speaking to CIP-30 implementors it seems reasonable that there does not exist implementations or motivation to support witnessing stake pool certificates via wallet web bridges. This is because stake pool operators much prefer the utility and security advantages not operating via light wallets. Due to the Lack of Specificity of CIP-30 we felt it necessary to explicitly state the lack of support in this extension.

Constitutional committee certificates are not supported by this specification's .signTx() for two reasons. First, this specification is only focussed on the need's of Ada holders and DReps. Secondly, the credentials used by the constitutional committee, are a hot and cold key setup. Hot and cold keys are not suited for standard light wallets.

Genesis key delegation and move instantaneous reward certificates (see in Shelley spec) are not supported here because they have been deprecated in the Conway ledger era. Furthermore, due to the lack of accessibility (require access to genesis keys) for these certificates it is extremely unlikely any CIP-30 implementations supported these.

The Role of the Wallet

The endpoints specified here aim to maintain the role of the wallet as: sharing public keys, transaction inspecting, transaction signing and transaction submission.

Transaction Inspection

In a previous design we had stipulated the precise information that must be shown to user by wallets at signature time. This was discussed during the wallets and tooling hackathon and consensus was reached that is not the place of these APIs to prescribe such details to wallets. Rather this specification should be describing the interface between web-based stacks and wallets and not telling wallets what UI elements should be used. It is in a wallet's best interest to always adequately inform the user, with varying levels of detail based on the wallet's discretion.

Transaction Construction

By not placing the burden of transaction construction onto the wallet, we move the application specific complexity from wallet implementations and onto applications. This has a number of benefits, primarily this should lower the bar for wallet adoption. But this also helps in the creation of iterative updates, all wallet implementers do not need to update if the format of these transactions is adjusted during development.

Here we also benefit from imitating the existing flows which have been utilized by CIP-30 compliant systems. Reusing existing flows is beneficial for developer adoption as it enables straight forward code reuse.

One argument against this design is that, if wallets are required to be able to inspect and thus understand these application specific transactions then they may as well build the transaction. Ultimately, we have taken the design decision to leave transaction construction to the applications.

CIP-30 Reuse

Whilst CIP-30 facilitated the launch of dApp client development on Cardano, it's functionality is limited in scope. Although it does offer generic functions, these cannot satisfy the problem that this proposal tackles in a backwards compatible manner. Thus extending it's functionality is a necessity.

Lack of Specificity

The CIP-30 specification has required amendments to add clarification to it's ambiguity. There is further ambiguity around what is and is not supported via .signTx(). The specification does not explicitly list the transaction artifacts wallets has to be able to inspect and witness. Whilst for most use cases this is likely fine and has served the community well. We forsee issues around large ledger upgrades which introduce new types of transaction fields and certificate. Without explicit mention of what is and is not supported deltas between expected and actual functionality become common and hazardous. This is why we choose to explicitly list those items that wallet have to support when complying with this API.

Extension Design

With this specification we chose to extend CIP-30's functionalities. There would be two competing designs to this approach. One; move to have this specification included within CIP-30. Two; deploy this specification as it's own standalone web-bridge.

It would be undesirable to include this functionality within the base CIP-30 API because it would force all wallets supporting CIP-30 to support this API. This is undesirable because not all client apps or wallets will have the need or desire to support this specification.

The reason we chose to not deploy this specification on its own is because it is unlikely that clients implementing this API will not want to also use the functionality offered by CIP-30. Additionally, CIP-30 offers a extensibility mechanism meaning that the initial handshake connection is defined and thus wont be needed to be defined within this specification.

Furthermore, another benefit of utilizing the CIP-30 extensibility mechanism is the potential for siloing of wallet capabilities between client apps. By having to request access to each extension wallets and users are able to silo which extensions they allow to each client application. An example of this could be only allowing the CIP-95 API with governance related applications and not decentralized extensions.

Backwards Compatibility

The primary issue with just using CIP-30 to inspect, sign and submit Conway transactions/certificates is that wallet implementations are likely incompatible. This is because such certificates/transactions were not part of the ledger design at time of original CIP-30 implementation. Furthermore, CIP-30 was written and implemented before voting credentials were defined and thus it would be impossible to provide signatures with this credential to votes, DRep registrations and DRep retirements.

Although it is likely that some of the capabilities of this API can be achieved by existing CIP-30 implementations it is not certain how much. We would like to avoid the potential mismatching of capabilities between CIP-30 implementations, as this creates unpredictable wallet behavior for client applications. Such behavior was a primary motivator to introduce such an extendability mechanism to CIP-30.

Namespacing

In this specification we have chosen to explicitly namespace all endpoint except .signTx() where we omit the namespacing. By not namespacing .signTx() we intend to offer client apps an override of the CIP-30 .signTx(). We chose to do this because this .signTx() extends the CIP-30 functionality in a backwards compatible way. All other endpoints are namespaced to avoid possible collisions with other future extensions.

Inheriting Endpoints

In this design we chose to extend the capabilities of CIP-30's .signTx() and .signData() rather than introducing new endpoints for signing and submission. This was a result of community discussion at the wallets and tooling hackathon, leading to a more straight forward design. Originally we had individual endpoints for sign and submitting of DRep registration, DRep retirement, votes, governance actions and vote delegations.

Whilst individual endpoints seem like a simpler solution they would likely introduce more complexities for wallet implementors. As constraining what transactions an endpoint would require additional validation complexities and error handling from wallets. For example; what should a wallet do if it is passed a DRep registration certificate via .signTx()? should it witness or reject and only witness with a dedicated DRep registration endpoint?

Furthermore individual restrictive endpoints limit how much can be done in a single transaction. These methods would not allow multiple certificates to be supplied at once. Thus client apps would be limited to a single governance artifact per transaction. This is limiting as it means users have to submit multiple transactions to achieve what is possible in one.

CIP-95 as a Conway Flag

By providing updated CIP-30 endpoints we essentially use the CIP-95 extension object as a flag to signal to apps at connection time a wallet's compatibility with Conway leger era. This goes against how past ledger feature upgrades have rolled out. Rather in the past, existing CIP-30 implementors have just updated their implementations, we believe this to be an error prone approach. This undoubted introduces deltas between what a client application expects a wallet to be able to do and what it can do. There is no way for a client application to know what a wallet is capable of.

Despite this we do not discourage CIP-30 implementors from updating their implementations to support Conway artifacts to .signData() and .signTx(). But if so they must support the CIP-95 object flag at connection time, so that clients are aware of this functionality.

Multi-stake Key Support

Although multi-stake key wallets are not widely adopted across Cardano, we make an effort to support them here. This is because a single stake key can delegate to a single DRep. By allowing users to spread stake across multiple stake keys it allows different weighted delegation to different DReps, this could be a very desirable feature.

Types of credential

This specification does not cater for wallets who manage non-key-based stake credentials and those who wish to handle non-key-based DRep credentials. This does limit the usefulness of this specification. But the complexities that would be introduced by generalization this specification to these credentials is unlikely to yield much benefit since these types of wallet are not prevalent in Cardano.

Although this means that we are likely excluding tooling for DAOs from being supported through this standard. The argument could be made that such entities generally prefer to use more advanced wallet tooling rather than relying on interaction with web-based stacks, thus it is not even certain DAOs would want to use such a standard.

Encoding

Unlike the CIP-30 specification we have made an decision, where possible to represent keys as raw hex rather than encoded representations. We believe that it is not the role of the wallet to encode such credentials, encoding needs should be at the application's discretion. Introducing different encodings into this API would add unneeded complexity.

Furthermore, in this API we chose to return public keys over key-hashes or addresses. Again we believe wallets should just serve public key information and it is up to the application to encode and derive addresses as needed. This simplifies the overall design and makes implementations easier for wallets.

Splitting of Stake Key endpoint

For stake keys we have chosen to implement two endpoints where wallets can share registered and unregistered stake keys. Originally we had a single endpoint which only allowed sharing of registered stake keys. This was problematic for wallets which had no registered stake keys, and thus the second endpoint was introduced.

We chose to keep a single endpoint for DRep keys, although it would have been possible to introduce a second to allow for wallets to activity of their DRep keys. This was just for the simplicity of the API. Furthermore, due to the design of this proposal it is unlikely that wallets will implement methods to track a user's DRep state.

Backwards Compatibility

This proposal should not effect the backwards compatibility of either clients or wallet implementors.

CIP-62?

CIP-62? | Cardano dApp-Wallet Web Bridge Catalyst Extension is another extension to the CIP-30 API, this proposal is independent of CIP-95. The CIP-95 specification does not rely on any of the implementation defined in CIP-62?. We have attempted to avoid any collisions of naming between these proposals, this was motivated by a desire to make wallet implementations more straight forward for wallets implementing both APIs.

Open Questions

• The burden of transaction building to be placed on dApps or wallets?
  • As we are replacing CIP-30's signTx it makes sense to follow the same flow and place the burden on the client applications.
• Does supporting governance action submission a necessary burden for the scope of this proposal?
  • Since moving burden of transaction construction from wallet to app, this becomes much less of an issue as the complex error checking should now be done by the application.
• should provide support for combination certificates?
  • Yes we will support ALL conway ledger era Tx/Certs, this will allow for CIP95 to be "the Conway compatible" wallet web bridge.
• Is it necessary to provide a method to prove ownership of DRep key?
  • Yes, this will be a useful add.
• Is it sensible to place multi-stake key burden onto clients?
  • Yes, seems like a reasonable approach. If wallets want to manage it, they can only provide the keys they wish.
• Do we need to share stake keys or can we just reuse reward addresses?
  • Reusing CIP30's .getRewardAddresses() may act as an alternative, but it is unclear how implementors have supported this function and thus its reuse maybe a mistake.
  • It is a more reasonable approach to share public key material instead of addresses as it gives the client application more freedom.
• Should this proposal cater for non-key-based stake credential?
  • We can leave this for a future iteration.
• Move DRep key definitions be moved into another CIP?
  • Yes, this is a cleaner approach, as we keep the purity of this proposal to being a wallet web bridge.
• Should there be a way for the optional sharing of governance state, from wallet to client?
  • We leave this for future CIPs.
• Should DRep key be moved into CIP-1852?
  • Yes it will be moved to it's own CIP with reference added to CIP-1852.

Path to Active

Acceptance Criteria

• The interface is supported by three wallet providers.
  • Nufi
  • Lace
  • Yoroi
  • demos wallet
• The interface is used by one web application to allow users to engage with the Conway ledger design.
  • SanchoNet GovTool
  • GovTool
  • cip95-cardano-wallet-connector
  • drep-campaign-platform
• The interface is supported via libraries.
  • Cardano JS-SDK
  • purescript-cip95
  • Mesh SDK

Implementation Plan

• Provide a public Discord channel for open discussion of this specification.
  • See wallets-sanchonet channel in the IOG Technical Discord under (to view you have to opt-in to the Sanchonet group in the start-here channel).
• Author to engage with wallet providers for feedback.
• Author to run a hackathon workshop with wallet providers.
  • In person and online hackathon run 2023.07.13, outcomes presented here: CIP-95 pull request comment.
• Resolve all Open Questions.
• Author to provide test dApp to test against.
  • See cip95-cardano-wallet-connector.
• Author to provide a reference wallet implementation.
  • See cip95-demos-wallet.
• Author to produce a set of test vectors for wallets to test against.
• Author to move DRep key definitions to a separate CIP.
  • via the addition of CIP-105 | Conway era Key Chains for HD Wallets via CIPs PR #597.

Acknowledgments

Wallets and Tooling Hackathon

On 2023.07.13 a online and in person community hackathon took place, aims of this event included maturation of the design of this specification.

We would like to thank the following attendees for providing their valuable insights:

• Piotr Czeglik - Lace
• Mircea Hasegan - Lace
• Alex Apeldoorn - Lace
• Michal Szorad - Yoroi
• Javier Bueno - Yoroi
• Ed Eykholt - Blocktrust
• Vladimir Volek - Five Binaries
• Marek Mahut - Five Binaries
• Markus Gufler - Cardano Foundation
• Michal Ciborowski - BinarApps

Copyright

This CIP is licensed under CC-BY-4.0.