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@solana/signers
This package provides an abstraction layer over signing messages and transactions in Solana. It can be used standalone, but it is also exported as part of the Solana JavaScript SDK @solana/web3.js@experimental
.
You can think of signers as an abstract way to sign messages and transactions. This could be using a Crypto KeyPair, a wallet adapter in the browser, a Noop signer for testing purposes, or anything you want. Here's an example using a CryptoKeyPair
signer:
import { pipe } from '@solana/functional';
import { generateKeyPairSigner } from '@solana/signers';
import { createTransactionMessage } from '@solana/transaction-messages';
import { compileTransaction } from '@solana/transactions';
const mySigner = await generateKeyPairSigner();
mySigner.address;
const myMessage = createSignableMessage('Hello world!');
const [messageSignatures] = await mySigner.signMessages([myMessage]);
const myTransactionMessage = pipe(
createTransactionMessage({ version: 0 }),
);
const myTransaction = compileTransaction(myTransactionMessage);
const [transactionSignatures] = await mySigner.signTransactions([myTransaction]);
As you can see, this provides a consistent API regardless of how things are being signed behind the scenes. If tomorrow we need to use a browser wallet instead, we'd simply need to swap the generateKeyPairSigner
function with the signer factory of our choice.
This package offers a total of five different types of signers that may be used in combination when applicable. Three of them allow us to sign transactions whereas the other two are used for regular message signing.
They are separated into three categories:
- Partial signers: Given a message or transaction, provide one or more signatures for it. These signers are not able to modify the given data which allows us to run many of them in parallel.
- Modifying signers: Can choose to modify a message or transaction before signing it with zero or more private keys. Because modifying a message or transaction invalidates any pre-existing signatures over it, modifying signers must do their work before any other signer.
- Sending signers: Given a transaction, signs it and sends it immediately to the blockchain. When applicable, the signer may also decide to modify the provided transaction before signing it. This interface accommodates wallets that simply cannot sign a transaction without sending it at the same time. This category of signers does not apply to regular messages.
Thus, we end up with the following interfaces.
| Partial signers | Modifying signers | Sending signers |
---|
TransactionSigner | TransactionPartialSigner | TransactionModifyingSigner | TransactionSendingSigner |
MessageSigner | MessagePartialSigner | MessageModifyingSigner | N/A |
We will go through each of these five signer interfaces and their respective characteristics in the documentation below.
This package also provides the following concrete signer implementations:
- The
KeyPairSigner
which uses a CryptoKeyPair
to sign messages and transactions. - The Noop signer which does not sign anything and is mostly useful for testing purposes or for indicating that an account will be signed in a different environment (e.g. sending a transaction to your server so it can sign it).
Additionally, this package allows transaction signers to be stored inside the account meta of an instruction. This allows us to create instructions by passing around signers instead of addresses when applicable which, in turn, allows us to sign an entire transaction automatically without having to scan through its instructions to find the required signers.
In the sections below, we'll go through all the provided signers in more detail before diving into storing signers inside instruction account metas and how to benefit from it.
Signing messages
Types
SignableMessage
Defines a message with any of the signatures that might have already been provided by other signers. This interface allows modifying signers to decide on whether or not they should modify the provided message depending on whether or not signatures already exist for such message. It also helps create a more consistent API by providing a structure analogous to transactions which also keep track of their signature dictionary.
type SignableMessage = {
content: Uint8Array;
signatures: SignatureDictionary;
};
MessagePartialSigner<TAddress>
An interface that signs an array of SignableMessages
without modifying their content. It defines a signMessages
function that returns a SignatureDictionary
for each provided message. Such signature dictionaries are expected to be merged with the existing ones if any.
const myMessagePartialSigner: MessagePartialSigner<'1234..5678'> = {
address: address('1234..5678'),
signMessages: async (messages: SignableMessage[]): Promise<SignatureDictionary[]> => {
},
};
Characteristics:
- Parallel. When multiple signers sign the same message, we can perform this operation in parallel to obtain all their signatures.
- Flexible order. The order in which we use these signers for a given message doesn’t matter.
MessageModifyingSigner<TAddress>
An interface that potentially modifies the content of the provided SignableMessages
before signing them. E.g. this enables wallets to prefix or suffix nonces to the messages they sign. For each message, instead of returning a SignatureDirectory
, its modifyAndSignMessages
function returns its updated SignableMessage
with a potentially modified content and signature dictionary.
const myMessageModifyingSigner: MessageModifyingSigner<'1234..5678'> = {
address: address('1234..5678'),
modifyAndSignMessages: async (messages: SignableMessage[]): Promise<SignableMessage[]> => {
},
};
Characteristics:
- Sequential. Contrary to partial signers, these cannot be executed in parallel as each call can modify the content of the message.
- First signers. For a given message, a modifying signer must always be used before a partial signer as the former will likely modify the message and thus impact the outcome of the latter.
- Potential conflicts. If more than one modifying signer is provided, the second signer may invalidate the signature of the first one. However, modifying signers may decide not to modify a message based on the existence of signatures for that message.
MessageSigner<TAddress>
Union interface that uses any of the available message signers.
type MessageSigner<TAddress extends string = string> =
| MessagePartialSigner<TAddress>
| MessageModifyingSigner<TAddress>;
Functions
createSignableMessage(content, signatures?)
Creates a SignableMessage
from a Uint8Array
or a UTF-8 string. It optionally accepts a signature dictionary if the message already contains signatures.
const myMessage = createSignableMessage(new Uint8Array([1, 2, 3]));
const myMessageFromText = createSignableMessage('Hello world!');
const myMessageWithSignatures = createSignableMessage('Hello world!', {
'1234..5678': new Uint8Array([1, 2, 3]),
});
Type guards
Each of the message interfaces described above comes with two type guards that allow us to check whether or not a given value is a message signer of the requested type. One that returns a boolean and one that asserts by throwing an error if the provided value is not of the expected interface.
const myAddress = address('1234..5678');
isMessagePartialSigner({ address: myAddress, signMessages: async () => {} });
isMessagePartialSigner({ address: myAddress });
assertIsMessagePartialSigner({ address: myAddress, signMessages: async () => {} });
assertIsMessagePartialSigner({ address: myAddress });
isMessageModifyingSigner({ address: myAddress, modifyAndSignMessages: async () => {} });
isMessageModifyingSigner({ address: myAddress });
assertIsMessageModifyingSigner({ address: myAddress, modifyAndSignMessages: async () => {} });
assertIsMessageModifyingSigner({ address: myAddress });
isMessageSigner({ address: myAddress, signMessages: async () => {} });
isMessageSigner({ address: myAddress, modifyAndSignMessages: async () => {} });
assertIsMessageSigner({ address: myAddress, signMessages: async () => {} });
assertIsMessageSigner({ address: myAddress, modifyAndSignMessages: async () => {} });
Signing transactions
Types
TransactionPartialSigner<TAddress>
An interface that signs an array of Transactions
without modifying their content. It defines a signTransactions
function that returns a SignatureDictionary
for each provided transaction. Such signature dictionaries are expected to be merged with the existing ones if any.
const myTransactionPartialSigner: TransactionPartialSigner<'1234..5678'> = {
address: address('1234..5678'),
signTransactions: async (transactions: Transaction[]): Promise<SignatureDictionary[]> => {
},
};
Characteristics:
- Parallel. It returns a signature directory for each provided transaction without modifying them, making it possible for multiple partial signers to sign the same transaction in parallel.
- Flexible order. The order in which we use these signers for a given transaction doesn’t matter.
TransactionModifyingSigner<TAddress>
An interface that potentially modifies the provided Transactions
before signing them. E.g. this enables wallets to inject additional instructions into the transaction before signing them. For each transaction, instead of returning a SignatureDirectory
, its modifyAndSignTransactions
function returns an updated Transaction
with a potentially modified set of instructions and signature dictionary.
const myTransactionModifyingSigner: TransactionModifyingSigner<'1234..5678'> = {
address: address('1234..5678'),
modifyAndSignTransactions: async <T extends Transaction>(transactions: T[]): Promise<T[]> => {
},
};
Characteristics:
- Sequential. Contrary to partial signers, these cannot be executed in parallel as each call can modify the provided transactions.
- First signers. For a given transaction, a modifying signer must always be used before a partial signer as the former will likely modify the transaction and thus impact the outcome of the latter.
- Potential conflicts. If more than one modifying signer is provided, the second signer may invalidate the signature of the first one. However, modifying signers may decide not to modify a transaction based on the existence of signatures for that transaction.
TransactionSendingSigner<TAddress>
An interface that signs one or multiple transactions before sending them immediately to the blockchain. It defines a signAndSendTransactions
function that returns the transaction signature (i.e. its identifier) for each provided CompilableTransaction
. This interface is required for PDA wallets and other types of wallets that don't provide an interface for signing transactions without sending them.
Note that it is also possible for such signers to modify the provided transactions before signing and sending them. This enables use cases where the modified transactions cannot be shared with the app and thus must be sent directly.
const myTransactionSendingSigner: TransactionSendingSigner<'1234..5678'> = {
address: address('1234..5678'),
signAndSendTransactions: async (transactions: Transaction[]): Promise<SignatureBytes[]> => {
},
};
Characteristics:
- Single signer. Since this signer also sends the provided transactions, we can only use a single
TransactionSendingSigner
for a given set of transactions. - Last signer. Trivially, that signer must also be the last one used.
- Potential conflicts. Since signers may decide to modify the given transactions before sending them, they may invalidate previous signatures. However, signers may decide not to modify a transaction based on the existence of signatures for that transaction.
- Potential confirmation. Whilst this is not required by this interface, it is also worth noting that most wallets will also wait for the transaction to be confirmed (typically with a
confirmed
commitment) before notifying the app that they are done.
TransactionSigner<TAddress>
Union interface that uses any of the available transaction signers.
type TransactionSigner<TAddress extends string = string> =
| TransactionPartialSigner<TAddress>
| TransactionModifyingSigner<TAddress>
| TransactionSendingSigner<TAddress>;
Functions
Type guards
Each of the transaction interfaces described above comes with two type guards that allow us to check whether or not a given value is a transaction signer of the requested type. One that returns a boolean and one that asserts by throwing an error if the provided value is not of the expected interface.
const myAddress = address('1234..5678');
isTransactionPartialSigner({ address: myAddress, signTransactions: async () => {} });
isTransactionPartialSigner({ address: myAddress });
assertIsTransactionPartialSigner({ address: myAddress, signTransactions: async () => {} });
assertIsTransactionPartialSigner({ address: myAddress });
isTransactionModifyingSigner({ address: myAddress, modifyAndSignTransactions: async () => {} });
isTransactionModifyingSigner({ address: myAddress });
assertIsTransactionModifyingSigner({ address: myAddress, modifyAndSignTransactions: async () => {} });
assertIsTransactionModifyingSigner({ address: myAddress });
isTransactionSendingSigner({ address: myAddress, signAndSignTransaction: async () => {} });
isTransactionSendingSigner({ address: myAddress });
assertIsTransactionSendingSigner({ address: myAddress, signAndSignTransaction: async () => {} });
assertIsTransactionSendingSigner({ address: myAddress });
isTransactionSigner({ address: myAddress, signTransactions: async () => {} });
isTransactionSigner({ address: myAddress, modifyAndSignTransactions: async () => {} });
isTransactionSigner({ address: myAddress, signAndSignTransaction: async () => {} });
assertIsTransactionSigner({ address: myAddress, signTransactions: async () => {} });
assertIsTransactionSigner({ address: myAddress, modifyAndSignTransactions: async () => {} });
assertIsTransactionSigner({ address: myAddress, signAndSignTransaction: async () => {} });
Creating and generating KeyPair signers
Types
KeyPairSigner<TAddress>
Defines a signer that uses a CryptoKeyPair
to sign messages and transactions. It implements both the MessagePartialSigner
and TransactionPartialSigner
interfaces and keeps track of the CryptoKeyPair
instance used to sign messages and transactions.
import { generateKeyPairSigner } from '@solana/signers';
const myKeyPairSigner = generateKeyPairSigner();
myKeyPairSigner.address;
myKeyPairSigner.keyPair;
const [myMessageSignatures] = await myKeyPairSigner.signMessages([myMessage]);
const [myTransactionSignatures] = await myKeyPairSigner.signTransactions([myTransaction]);
Functions
createSignerFromKeyPair()
Creates a KeyPairSigner
from a provided Crypto KeyPair. The signMessages
and signTransactions
functions of the returned signer will use the private key of the provided key pair to sign messages and transactions. Note that both the signMessages
and signTransactions
implementations are parallelized, meaning that they will sign all provided messages and transactions in parallel.
import { generateKeyPair } from '@solana/keys';
import { createSignerFromKeyPair, KeyPairSigner } from '@solana/signers';
const myKeyPair: CryptoKeyPair = await generateKeyPair();
const myKeyPairSigner: KeyPairSigner = await createSignerFromKeyPair(myKeyPair);
generateKeyPairSigner()
A convenience function that generates a new Crypto KeyPair and immediately creates a KeyPairSigner
from it.
import { generateKeyPairSigner } from '@solana/signers';
const myKeyPairSigner = await generateKeyPairSigner();
isKeyPairSigner()
A type guard that returns true
if the provided value is a KeyPairSigner
.
const myKeyPairSigner = await generateKeyPairSigner();
isKeyPairSigner(myKeyPairSigner);
isKeyPairSigner({ address: address('1234..5678') });
assertIsKeyPairSigner()
A type guard that throws an error if the provided value is not a KeyPairSigner
.
const myKeyPairSigner = await generateKeyPairSigner();
assertIsKeyPairSigner(myKeyPairSigner);
assertIsKeyPairSigner({ address: address('1234..5678') });
Creating Noop signers
For a given address, a Noop (No-Operation) signer can be created to offer an implementation of both the MessagePartialSigner
and TransactionPartialSigner
interfaces such that they do not sign anything. Namely, signing a transaction or a message with a NoopSigner
will return an empty SignatureDictionary
.
This signer may be useful:
- For testing purposes.
- For indicating that a given account is a signer and taking the responsibility to provide the signature for that account ourselves. For instance, if we need to send the transaction to a server that will sign it and send it for us.
Types
NoopSigner<TAddress>
Defines a Noop (No-Operation) signer.
const myNoopSigner: NoopSigner;
myNoopSigner satisfies MessagePartialSigner;
myNoopSigner satisfies TransactionPartialSigner;
Functions
createNoopSigner()
Creates a Noop (No-Operation) signer from a given address.
import { createNoopSigner } from '@solana/signers';
const myNoopSigner = createNoopSigner(address('1234..5678'));
const [myMessageSignatures] = await myNoopSigner.signMessages([myMessage]);
const [myTransactionSignatures] = await myNoopSigner.signTransactions([myTransaction]);
Storing transaction signers inside instruction account metas
This package defines an alternative definition for account metas that allows us to store TransactionSigners
inside them. This means each instruction can keep track of its own set of signers and, by extension, so can transactions.
It also provides helper functions that deduplicate and extract signers from instructions and transactions which makes it possible to sign an entire transaction automatically as we will see in the next section.
Types
IAccountSignerMeta
Alternative IAccountMeta
definition for signer accounts that allows us to store TransactionSigners
inside it.
const mySignerMeta: IAccountSignerMeta = {
address: myTransactionSigner.address,
role: AccountRole.READONLY_SIGNER,
signer: myTransactionSigner,
};
IInstructionWithSigners
Composable type that allows IAccountSignerMetas
to be used inside the instruction's accounts
array.
const myInstructionWithSigners: IInstruction & IInstructionWithSigners = {
programAddress: address('1234..5678'),
accounts: [
{
address: myTransactionSigner.address,
role: AccountRole.READONLY_SIGNER,
signer: myTransactionSigner,
},
],
};
ITransactionMessageWithSigners
Composable type that allows IAccountSignerMetas
to be used inside all of the transaction message's account metas.
const myTransactionMessageWithSigners: BaseTransactionMessage & ITransactionMessageWithSigners = {
instructions: [
myInstructionA as IInstruction & IInstructionWithSigners,
myInstructionB as IInstruction & IInstructionWithSigners,
myInstructionC as IInstruction,
],
version: 0,
};
Functions
getSignersFromInstruction()
Extracts and deduplicates all signers stored inside the account metas of an instruction.
const mySignerA = { address: address('1111..1111'), signTransactions: async () => {} };
const mySignerB = { address: address('2222..2222'), signTransactions: async () => {} };
const myInstructionWithSigners: IInstructionWithSigners = {
programAddress: address('1234..5678'),
accounts: [
{ address: mySignerA.address, role: AccountRole.READONLY_SIGNER, signer: mySignerA },
{ address: mySignerB.address, role: AccountRole.WRITABLE_SIGNER, signer: mySignerB },
{ address: mySignerA.address, role: AccountRole.WRITABLE_SIGNER, signer: mySignerA },
],
};
const instructionSigners = getSignersFromInstruction(myInstructionWithSigners);
getSignersFromTransactionMessage()
Similarly to getSignersFromInstruction
, this function extracts and deduplicates all signers stored inside the account metas of all the instructions inside a transaction message.
const transactionSigners = getSignersFromTransactionMessage(myTransactionMessageWithSigners);
addSignersToInstruction()
Helper function that adds the provided signers to any of the applicable account metas. For an account meta to match a provided signer it:
- Must have a signer role (
AccountRole.READONLY_SIGNER
or AccountRole.WRITABLE_SIGNER
). - Must have the same address as the provided signer.
- Must not have an attached signer already.
const myInstruction: IInstruction = {
accounts: [
{ address: '1111' as Address, role: AccountRole.READONLY_SIGNER },
{ address: '2222' as Address, role: AccountRole.WRITABLE_SIGNER },
],
};
const mySignerA: TransactionSigner<'1111'>;
const mySignerB: TransactionSigner<'2222'>;
const myInstructionWithSigners = addSignersToInstruction([mySignerA, mySignerB], myInstruction);
addSignersToTransactionMessage()
Similarly to addSignersToInstruction
, this function adds signer to all the applicable account metas of all the instructions inside a transaction message.
const myTransactionMessageWithSigners = addSignersToTransactionMessage(mySigners, myTransactionMessage);
Signing transactions with signers
As we've seen in the previous section, we can store and extract TransactionSigners
from instructions and transaction messages. This allows us to provide helper methods that sign transaction messages using the signers stored inside them.
Functions
partiallySignTransactionMessageWithSigners()
Extracts all signers inside the provided transaction message and uses them to sign it. It first uses all TransactionModifyingSigners
sequentially before using all TransactionPartialSigners
in parallel.
If a composite signer implements both interfaces, it will be used as a modifying signer if no other signer implements that interface. Otherwise, it will be used as a partial signer.
const mySignedTransaction = await partiallySignTransactionMessageWithSigners(myTransactionMessage);
It also accepts an optional AbortSignal
that will be propagated to all signers.
const mySignedTransaction = await partiallySignTransactionMessageWithSigners(myTransactionMessage, {
abortSignal: myAbortController.signal,
});
Finally, note that this function ignores TransactionSendingSigners
as it does not send the transaction. See the signAndSendTransactionMessageWithSigners
function below for more details on how to use sending signers.
signTransactionMessageWithSigners()
This function works the same as the partiallySignTransactionMessageWithSigners
function described above except that it also ensures the transaction is fully signed before returning it. An error will be thrown if that's not the case.
const mySignedTransaction = await signTransactionMessageWithSigners(myTransactionMessage);
const mySignedTransaction = await signTransactionMessageWithSigners(myTransactionMessage, {
abortSignal: myAbortController.signal,
});
mySignedTransaction satisfies IFullySignedTransaction;
signAndSendTransactionMessageWithSigners()
Extracts all signers inside the provided transaction and uses them to sign it before sending it immediately to the blockchain. It returns the signature of the sent transaction (i.e. its identifier).
const transactionSignature = await signAndSendTransactionMessageWithSigners(transactionMessage);
const transactionSignature = await signAndSendTransactionMessageWithSigners(transactionMessage, {
abortSignal: myAbortController.signal,
});
Similarly to the partiallySignTransactionMessageWithSigners
function, it first uses all TransactionModifyingSigners
sequentially before using all TransactionPartialSigners
in parallel. It then sends the transaction using the TransactionSendingSigner
it identified.
Here as well, composite transaction signers are treated such that at least one sending signer is used if any. When a TransactionSigner
implements more than one interface, use it as a:
TransactionSendingSigner
, if no other TransactionSendingSigner
exists.TransactionModifyingSigner
, if no other TransactionModifyingSigner
exists.TransactionPartialSigner
, otherwise.
The provided transaction must contain exactly one TransactionSendingSigner
inside its account metas. If more than one composite signers implement the TransactionSendingSigner
interface, one of them will be selected as the sending signer. Otherwise, if multiple TransactionSendingSigners
must be selected, the function will throw an error.
If you'd like to assert that a transaction makes use of exactly one TransactionSendingSigner
before calling this function, you may use the assertIsTransactionMessageWithSingleSendingSigner
function.
assertIsTransactionMessageWithSingleSendingSigner(transactionMessage);
const transactionSignature = await signAndSendTransactionMessageWithSigners(transactionMessage);
Alternatively, you may use the isTransactionWithSingleSendingSigner()
function to provide a fallback in case the transaction does not contain any sending signer.
let transactionSignature: SignatureBytes;
if (isTransactionWithSingleSendingSigner(transactionMessage)) {
transactionSignature = await signAndSendTransactionMessageWithSigners(transactionMessage);
} else {
const signedTransaction = await signTransactionMessageWithSigners(transactionMessage);
const encodedTransaction = getBase64EncodedWireTransaction(signedTransaction);
transactionSignature = await rpc.sendTransaction(encodedTransaction).send();
}