diff --git a/api-specs/openrpc-signing-api.json b/api-specs/openrpc-signing-api.json
index 5795ff153..eefb3d50a 100644
--- a/api-specs/openrpc-signing-api.json
+++ b/api-specs/openrpc-signing-api.json
@@ -25,10 +25,9 @@
                                 "type": "string",
                                 "description": "Hash of the prepared transaction that will be signed."
                             },
-                            "publicKey": {
-                                "title": "publicKey",
-                                "type": "string",
-                                "description": "Public key to use to sign the transaction."
+                            "keyIdentifier": {
+                                "$ref": "#/components/schemas/KeyIdentifier",
+                                "description": "Identifier for the key to use for signing. At least one of publicKey or id must be provided."
                             },
                             "internalTxId": {
                                 "title": "internalTxId",
@@ -36,7 +35,7 @@
                                 "description": "Internal txId used by the Wallet Gateway to store the transaction."
                             }
                         },
-                        "required": ["tx", "txHash", "publicKey"]
+                        "required": ["tx", "txHash", "keyIdentifier"]
                     }
                 }
             ],
@@ -279,6 +278,54 @@
                 "type": "null",
                 "description": "Represents a null value, used in responses where no data is returned."
             },
+            "KeyIdentifierWithPublicKey": {
+                "title": "KeyIdentifierWithPublicKey",
+                "type": "object",
+                "properties": {
+                    "publicKey": {
+                        "title": "publicKey",
+                        "type": "string",
+                        "description": "Public key to use to sign the transaction."
+                    },
+                    "id": {
+                        "title": "id",
+                        "type": "string",
+                        "description": "Unique identifier for the key"
+                    }
+                },
+                "required": ["publicKey"],
+                "description": "Key identifier with publicKey (id is optional)."
+            },
+            "KeyIdentifierWithId": {
+                "title": "KeyIdentifierWithId",
+                "type": "object",
+                "properties": {
+                    "publicKey": {
+                        "title": "publicKey",
+                        "type": "string",
+                        "description": "Public key to use to sign the transaction."
+                    },
+                    "id": {
+                        "title": "id",
+                        "type": "string",
+                        "description": "Unique identifier for the key"
+                    }
+                },
+                "required": ["id"],
+                "description": "Key identifier with id (publicKey is optional)."
+            },
+            "KeyIdentifier": {
+                "title": "KeyIdentifier",
+                "oneOf": [
+                    {
+                        "$ref": "#/components/schemas/KeyIdentifierWithPublicKey"
+                    },
+                    {
+                        "$ref": "#/components/schemas/KeyIdentifierWithId"
+                    }
+                ],
+                "description": "Identifier for a key. At least one of publicKey or id must be provided (both can also be provided)."
+            },
             "Key": {
                 "title": "Key",
                 "type": "object",
diff --git a/core/signing-blockdaemon/src/index.ts b/core/signing-blockdaemon/src/index.ts
index a9bf87606..31003dfff 100644
--- a/core/signing-blockdaemon/src/index.ts
+++ b/core/signing-blockdaemon/src/index.ts
@@ -49,10 +49,19 @@ export default class BlockdaemonSigningDriver implements SigningDriverInterface
                 params: SignTransactionParams
             ): Promise<SignTransactionResult> => {
                 try {
+                    if (!params.keyIdentifier.publicKey) {
+                        return {
+                            error: 'key_not_found',
+                            error_description:
+                                'The provided key identifier must include a publicKey.',
+                        }
+                    }
                     const tx = await this.client.signTransaction({
                         tx: params.tx,
                         txHash: params.txHash,
-                        publicKey: params.publicKey,
+                        keyIdentifier: {
+                            publicKey: params.keyIdentifier.publicKey,
+                        },
                         internalTxId: params.internalTxId,
                     })
                     return {
diff --git a/core/signing-fireblocks/src/fireblocks.test.ts b/core/signing-fireblocks/src/fireblocks.test.ts
index 52257d990..689804d27 100644
--- a/core/signing-fireblocks/src/fireblocks.test.ts
+++ b/core/signing-fireblocks/src/fireblocks.test.ts
@@ -38,7 +38,10 @@ describe('fireblocks handler', () => {
             const transaction = await handler.signTransaction(
                 userId,
                 TEST_TRANSACTION_HASH,
-                '02fefbcc9aebc8a479f211167a9f564df53aefd603a8662d9449a98c1ead2eba'
+                {
+                    publicKey:
+                        '02fefbcc9aebc8a479f211167a9f564df53aefd603a8662d9449a98c1ead2eba',
+                }
             )
             expect(transaction).toBeDefined()
             const foundTransaction = await handler.getTransaction(
diff --git a/core/signing-fireblocks/src/fireblocks.ts b/core/signing-fireblocks/src/fireblocks.ts
index 82a95c87c..6279e0851 100644
--- a/core/signing-fireblocks/src/fireblocks.ts
+++ b/core/signing-fireblocks/src/fireblocks.ts
@@ -8,7 +8,11 @@ import {
     VaultAccount,
 } from '@fireblocks/ts-sdk'
 import { pino } from 'pino'
-import { SigningStatus, CC_COIN_TYPE } from '@canton-network/core-signing-lib'
+import {
+    SigningStatus,
+    CC_COIN_TYPE,
+    KeyIdentifier,
+} from '@canton-network/core-signing-lib'
 import { z } from 'zod'
 
 const RawMessageSchema = z.object({
@@ -307,19 +311,26 @@ export class FireblocksHandler {
     }
     /**
      * Sign a transaction using a public key
-     * @param tx - The transaction to sign, as a string
-     * @param publicKey - The public key to use for signing
+     * @param userId - id of a user to get respective client and keys
+     * @param txHash - Hash of the transaction to sign
+     * @param keyIdentifier - The key identifier (must include publicKey)
      * @param externalTxId - The transaction ID assigned by the Wallet Gateway
      * @return The transaction object from Fireblocks
      */
     public async signTransaction(
         userId: string | undefined,
-        tx: string,
-        publicKey: string,
+        txHash: string,
+        keyIdentifier: KeyIdentifier,
         externalTxId?: string
     ): Promise<FireblocksTransaction> {
         try {
             const client = this.getClient(userId)
+            if (!keyIdentifier.publicKey) {
+                throw new Error(
+                    'Public key is required for Fireblocks signing provider'
+                )
+            }
+            const publicKey = keyIdentifier.publicKey
             if (!this.keyInfoByPublicKey.has(publicKey)) {
                 // refresh the keycache
                 await this.getPublicKeys(userId)
@@ -338,7 +349,7 @@ export class FireblocksHandler {
                         rawMessageData: {
                             messages: [
                                 {
-                                    content: tx,
+                                    content: txHash,
                                     derivationPath: key.derivationPath,
                                 },
                             ],
diff --git a/core/signing-fireblocks/src/index.test.ts b/core/signing-fireblocks/src/index.test.ts
index b40cee4b3..8769453f2 100644
--- a/core/signing-fireblocks/src/index.test.ts
+++ b/core/signing-fireblocks/src/index.test.ts
@@ -197,7 +197,9 @@ test('transaction signature', async () => {
     const tx = await controller.signTransaction({
         tx: TEST_TRANSACTION,
         txHash: TEST_TRANSACTION_HASH,
-        publicKey: key.publicKey,
+        keyIdentifier: {
+            publicKey: key.publicKey,
+        },
     })
 
     throwWhenRpcError(tx)
diff --git a/core/signing-fireblocks/src/index.ts b/core/signing-fireblocks/src/index.ts
index 218cac1b2..1b7889cb2 100644
--- a/core/signing-fireblocks/src/index.ts
+++ b/core/signing-fireblocks/src/index.ts
@@ -85,7 +85,7 @@ export default class FireblocksSigningDriver implements SigningDriverInterface {
                     const tx = await this.fireblocks.signTransaction(
                         userId,
                         params.txHash,
-                        params.publicKey,
+                        params.keyIdentifier,
                         params.internalTxId
                     )
                     return {
diff --git a/core/signing-internal/src/controller.test.ts b/core/signing-internal/src/controller.test.ts
index 1dc04e045..53df2f578 100644
--- a/core/signing-internal/src/controller.test.ts
+++ b/core/signing-internal/src/controller.test.ts
@@ -78,7 +78,9 @@ test('transaction signature', async () => {
     const tx = await controller.signTransaction({
         tx: TEST_TRANSACTION,
         txHash: TEST_TRANSACTION_HASH,
-        publicKey: key.publicKey,
+        keyIdentifier: {
+            publicKey: key.publicKey,
+        },
     })
 
     if (isRpcError(tx)) {
diff --git a/core/signing-internal/src/controller.ts b/core/signing-internal/src/controller.ts
index 66a355978..2964d73dc 100644
--- a/core/signing-internal/src/controller.ts
+++ b/core/signing-internal/src/controller.ts
@@ -75,9 +75,18 @@ export class InternalSigningDriver implements SigningDriverInterface {
             ): Promise<SignTransactionResult> => {
                 // TODO: validate transaction here
 
+                if (!params.keyIdentifier.publicKey) {
+                    return Promise.resolve({
+                        error: 'key_not_found',
+                        error_description:
+                            'The provided key identifier must include a publicKey.',
+                    })
+                }
+
                 const key = await this.store.getSigningKeyByPublicKey(
-                    params.publicKey
+                    params.keyIdentifier.publicKey
                 )
+
                 if (key?.privateKey && _userId) {
                     const txId = randomUUID()
                     const signature = signTransactionHash(
@@ -90,7 +99,7 @@ export class InternalSigningDriver implements SigningDriverInterface {
                         id: txId,
                         hash: params.txHash,
                         signature,
-                        publicKey: params.publicKey,
+                        publicKey: params.keyIdentifier.publicKey,
                         createdAt: now,
                         status: 'signed',
                         updatedAt: now,
diff --git a/core/signing-lib/src/SigningDriverStore.ts b/core/signing-lib/src/SigningDriverStore.ts
index a1026c069..a38f37a2f 100644
--- a/core/signing-lib/src/SigningDriverStore.ts
+++ b/core/signing-lib/src/SigningDriverStore.ts
@@ -13,6 +13,10 @@ export interface SigningDriverStore {
         keyId: string
     ): Promise<SigningKey | undefined>
     getSigningKeyByPublicKey(publicKey: string): Promise<SigningKey | undefined>
+    getSigningKeyByName(
+        userId: string,
+        name: string
+    ): Promise<SigningKey | undefined>
     listSigningTransactionsByTxIdsAndPublicKeys(
         txIds: string[],
         publicKeys: string[]
diff --git a/core/signing-lib/src/rpc-gen/typings.ts b/core/signing-lib/src/rpc-gen/typings.ts
index 22706409e..e17ca4daf 100644
--- a/core/signing-lib/src/rpc-gen/typings.ts
+++ b/core/signing-lib/src/rpc-gen/typings.ts
@@ -21,6 +21,38 @@ export type TxHash = string
  *
  */
 export type PublicKey = string
+/**
+ *
+ * Unique identifier for the key
+ *
+ */
+export type Id = string
+/**
+ *
+ * Key identifier with publicKey (id is optional).
+ *
+ */
+export interface KeyIdentifierWithPublicKey {
+    publicKey: PublicKey
+    id?: Id
+    [k: string]: any
+}
+/**
+ *
+ * Key identifier with id (publicKey is optional).
+ *
+ */
+export interface KeyIdentifierWithId {
+    publicKey?: PublicKey
+    id: Id
+    [k: string]: any
+}
+/**
+ *
+ * Identifier for the key to use for signing. At least one of publicKey or id must be provided.
+ *
+ */
+export type KeyIdentifier = KeyIdentifierWithPublicKey | KeyIdentifierWithId
 /**
  *
  * Internal txId used by the Wallet Gateway to store the transaction.
@@ -106,12 +138,6 @@ export interface ObjectOfTransactionsUOtaZpXE {
     transactions?: Transactions
     [k: string]: any
 }
-/**
- *
- * Unique identifier for the key
- *
- */
-export type Id = string
 export interface Key {
     id: Id
     name: Name
@@ -127,7 +153,7 @@ export type Keys = Key[]
 export interface SignTransactionParams {
     tx: Tx
     txHash: TxHash
-    publicKey: PublicKey
+    keyIdentifier: KeyIdentifier
     internalTxId?: InternalTxId
     [k: string]: any
 }
diff --git a/core/signing-participant/src/controller.test.ts b/core/signing-participant/src/controller.test.ts
index 408ed7de4..3e00e3e71 100644
--- a/core/signing-participant/src/controller.test.ts
+++ b/core/signing-participant/src/controller.test.ts
@@ -28,7 +28,7 @@ test('transaction signature', async () => {
         .signTransaction({
             tx: TEST_TRANSACTION,
             txHash: TEST_TRANSACTION_HASH,
-            publicKey: '',
+            keyIdentifier: { publicKey: '' },
         })
     expect(tx.status).toBe('signed')
 })
diff --git a/core/signing-store-sql/src/store-sql.ts b/core/signing-store-sql/src/store-sql.ts
index 778243db9..326b5cc4f 100644
--- a/core/signing-store-sql/src/store-sql.ts
+++ b/core/signing-store-sql/src/store-sql.ts
@@ -75,6 +75,19 @@ export class StoreSql implements SigningDriverStore, AuthAware<StoreSql> {
         return result ? toSigningKey(result) : undefined
     }
 
+    async getSigningKeyByName(
+        userId: string,
+        name: string
+    ): Promise<SigningKey | undefined> {
+        const result = await this.db
+            .selectFrom('signingKeys')
+            .selectAll()
+            .where('userId', '=', userId)
+            .where('name', '=', name)
+            .executeTakeFirst()
+        return result ? toSigningKey(result) : undefined
+    }
+
     async setSigningKey(userId: string, key: SigningKey): Promise<void> {
         const serialized = fromSigningKey(key, userId)
 
diff --git a/wallet-gateway/remote/src/user-api/controller.ts b/wallet-gateway/remote/src/user-api/controller.ts
index c5fd4e8af..bc142d0a1 100644
--- a/wallet-gateway/remote/src/user-api/controller.ts
+++ b/wallet-gateway/remote/src/user-api/controller.ts
@@ -203,7 +203,9 @@ export const userController = (
                             const { signature } = await driver.signTransaction({
                                 tx: '',
                                 txHash: hash,
-                                publicKey: key.publicKey,
+                                keyIdentifier: {
+                                    publicKey: key.publicKey,
+                                },
                             })
 
                             return signature
@@ -282,7 +284,9 @@ export const userController = (
                             await driver.signTransaction({
                                 tx: Buffer.from(txPayload).toString('base64'),
                                 txHash: transactions.multiHash,
-                                publicKey: key.publicKey,
+                                keyIdentifier: {
+                                    publicKey: key.publicKey,
+                                },
                                 internalTxId,
                             })
 
@@ -376,7 +380,9 @@ export const userController = (
                                     transactions.multiHash,
                                     'base64'
                                 ).toString('hex'),
-                                publicKey: key.publicKey,
+                                keyIdentifier: {
+                                    publicKey: key.publicKey,
+                                },
                             })
                         if (status === 'signed') {
                             const { signature } = await driver.getTransaction({
@@ -500,7 +506,9 @@ export const userController = (
                     const signature = await driver.signTransaction({
                         tx: preparedTransaction,
                         txHash: preparedTransactionHash,
-                        publicKey: wallet.publicKey,
+                        keyIdentifier: {
+                            publicKey: wallet.publicKey,
+                        },
                     })
 
                     if (!signature.signature) {
@@ -543,7 +551,9 @@ export const userController = (
                     let result = await driver.signTransaction({
                         tx: preparedTransaction,
                         txHash: preparedTransactionHash,
-                        publicKey: wallet.publicKey,
+                        keyIdentifier: {
+                            publicKey: wallet.publicKey,
+                        },
                         internalTxId,
                     })