diff --git a/system-tests/test/deposit-redemption.test.ts b/system-tests/test/deposit-redemption.test.ts
index f89994552..2ebdddf75 100644
--- a/system-tests/test/deposit-redemption.test.ts
+++ b/system-tests/test/deposit-redemption.test.ts
@@ -65,7 +65,6 @@ describe("System Test - Deposit and redemption", () => {
   let maintainerBridgeHandle: EthereumBridge
   let depositorBridgeHandle: EthereumBridge
   let walletRegistryHandle: EthereumWalletRegistry
-  let tbtcContracts: TBTCContracts
 
   let walletTx: WalletTx
   let maintenanceService: MaintenanceService
@@ -132,7 +131,7 @@ describe("System Test - Deposit and redemption", () => {
       signerOrProvider: depositor,
     })
 
-    tbtcContracts = {
+    const tbtcContracts: TBTCContracts = {
       bridge: maintainerBridgeHandle,
       tbtcToken: tbtcTokenHandle,
       tbtcVault: vaultHandle,
@@ -140,7 +139,6 @@ describe("System Test - Deposit and redemption", () => {
     }
 
     walletTx = new WalletTx(tbtcContracts, electrumClient)
-
     maintenanceService = new MaintenanceService(tbtcContracts, electrumClient)
 
     const bankDeploymentInfo = deployedContracts.Bank
@@ -277,6 +275,7 @@ describe("System Test - Deposit and redemption", () => {
         //       times for the same wallet.
         await maintenanceService.spv.submitDepositSweepProof(
           sweepUtxo.transactionHash,
+          // This is the first sweep of the given wallet so there is no main UTXO.
           {
             // The function expects an unprefixed hash.
             transactionHash: BitcoinTxHash.from(constants.HashZero),
@@ -340,13 +339,17 @@ describe("System Test - Deposit and redemption", () => {
 
           // Request redemption to depositor's address.
           redeemerOutputScript = `0014${BitcoinHashUtils.computeHash160(
-            systemTestsContext.depositorBitcoinKeyPair.publicKey.compressed
+            Hex.from(
+              systemTestsContext.depositorBitcoinKeyPair.publicKey.compressed
+            )
           )}`
 
           await depositorBridgeHandle.requestRedemption(
-            systemTestsContext.walletBitcoinKeyPair.publicKey.compressed,
+            Hex.from(
+              systemTestsContext.walletBitcoinKeyPair.publicKey.compressed
+            ),
             sweepUtxo,
-            redeemerOutputScript,
+            Hex.from(redeemerOutputScript),
             requestedAmount
           )
 
@@ -355,8 +358,10 @@ describe("System Test - Deposit and redemption", () => {
           )
 
           redemptionRequest = await maintainerBridgeHandle.pendingRedemptions(
-            systemTestsContext.walletBitcoinKeyPair.publicKey.compressed,
-            redeemerOutputScript
+            Hex.from(
+              systemTestsContext.walletBitcoinKeyPair.publicKey.compressed
+            ),
+            Hex.from(redeemerOutputScript)
           )
         })
 
@@ -411,7 +416,9 @@ describe("System Test - Deposit and redemption", () => {
                 await maintenanceService.spv.submitRedemptionProof(
                   redemptionTxHash,
                   sweepUtxo,
-                  systemTestsContext.walletBitcoinKeyPair.publicKey.compressed
+                  Hex.from(
+                    systemTestsContext.walletBitcoinKeyPair.publicKey.compressed
+                  )
                 )
 
                 console.log("Redemption proved on the bridge")
@@ -428,7 +435,9 @@ describe("System Test - Deposit and redemption", () => {
             it("should close the redemption request on the bridge", async () => {
               await expect(
                 maintainerBridgeHandle.pendingRedemptions(
-                  systemTestsContext.walletBitcoinKeyPair.publicKey.compressed,
+                  Hex.from(
+                    systemTestsContext.walletBitcoinKeyPair.publicKey.compressed
+                  ),
                   redemptionRequest.redeemerOutputScript
                 )
               ).to.be.rejectedWith(
@@ -466,6 +475,7 @@ describe("System Test - Deposit and redemption", () => {
           ),
           BitcoinNetwork.Testnet
         )
+
       const depositorUtxos =
         await electrumClient.findAllUnspentTransactionOutputs(
           depositorBitcoinAddress
@@ -638,13 +648,17 @@ describe("System Test - Deposit and redemption", () => {
 
           // Request redemption to depositor's address.
           redeemerOutputScript = `0014${BitcoinHashUtils.computeHash160(
-            systemTestsContext.depositorBitcoinKeyPair.publicKey.compressed
+            Hex.from(
+              systemTestsContext.depositorBitcoinKeyPair.publicKey.compressed
+            )
           )}`
 
           await depositorBridgeHandle.requestRedemption(
-            systemTestsContext.walletBitcoinKeyPair.publicKey.compressed,
+            Hex.from(
+              systemTestsContext.walletBitcoinKeyPair.publicKey.compressed
+            ),
             sweepUtxo,
-            redeemerOutputScript,
+            Hex.from(redeemerOutputScript),
             tbtcBalanceOfDepositor
           )
 
@@ -653,8 +667,10 @@ describe("System Test - Deposit and redemption", () => {
           )
 
           redemptionRequest = await maintainerBridgeHandle.pendingRedemptions(
-            systemTestsContext.walletBitcoinKeyPair.publicKey.compressed,
-            redeemerOutputScript
+            Hex.from(
+              systemTestsContext.walletBitcoinKeyPair.publicKey.compressed
+            ),
+            Hex.from(redeemerOutputScript)
           )
         })
 
@@ -715,7 +731,9 @@ describe("System Test - Deposit and redemption", () => {
                 await maintenanceService.spv.submitRedemptionProof(
                   redemptionTxHash,
                   sweepUtxo,
-                  systemTestsContext.walletBitcoinKeyPair.publicKey.compressed
+                  Hex.from(
+                    systemTestsContext.walletBitcoinKeyPair.publicKey.compressed
+                  )
                 )
 
                 console.log("Redemption proved on the bridge")
@@ -732,7 +750,9 @@ describe("System Test - Deposit and redemption", () => {
             it("should close the redemption request on the bridge", async () => {
               await expect(
                 maintainerBridgeHandle.pendingRedemptions(
-                  systemTestsContext.walletBitcoinKeyPair.publicKey.compressed,
+                  Hex.from(
+                    systemTestsContext.walletBitcoinKeyPair.publicKey.compressed
+                  ),
                   redemptionRequest.redeemerOutputScript
                 )
               ).to.be.rejectedWith(
diff --git a/system-tests/test/utils/bitcoin.ts b/system-tests/test/utils/bitcoin.ts
index a81126fa9..984922176 100644
--- a/system-tests/test/utils/bitcoin.ts
+++ b/system-tests/test/utils/bitcoin.ts
@@ -2,7 +2,7 @@
 // @ts-ignore
 import wifLib from "wif"
 import { ec as EllipticCurve } from "elliptic"
-import { assembleBitcoinSpvProof } from "@keep-network/tbtc-v2.ts"
+import { assembleBitcoinSpvProof, Hex } from "@keep-network/tbtc-v2.ts"
 
 import type { BitcoinTxHash, ElectrumClient } from "@keep-network/tbtc-v2.ts"
 import type { Contract } from "ethers"
@@ -26,21 +26,21 @@ export interface KeyPair {
    */
   wif: string
   /**
-   * Private key as an unprefixed hex string.
+   * Private key.
    */
-  privateKey: string
+  privateKey: Hex
   /**
    * Public key.
    */
   publicKey: {
     /**
-     * Compressed public key as a 33-byte hex string prefixed with 02 or 03.
+     * Compressed 33-byte-long public key prefixed with 02 or 03.
      */
-    compressed: string
+    compressed: Hex
     /**
-     * Uncompressed public key as an unprefixed hex string.
+     * Uncompressed public key.
      */
-    uncompressed: string
+    uncompressed: Hex
   }
 }
 
@@ -54,11 +54,13 @@ export function keyPairFromWif(wif: string): KeyPair {
   const keyPair = secp256k1.keyFromPrivate(privateKey)
   return {
     wif,
-    privateKey: keyPair.getPrivate("hex"),
+    privateKey: Hex.from(keyPair.getPrivate("hex")),
     publicKey: {
-      compressed: keyPair.getPublic().encodeCompressed("hex"),
+      compressed: Hex.from(keyPair.getPublic().encodeCompressed("hex")),
       // Trim the `04` prefix from the uncompressed key.
-      uncompressed: keyPair.getPublic().encode("hex", false).substring(2),
+      uncompressed: Hex.from(
+        keyPair.getPublic().encode("hex", false).substring(2)
+      ),
     },
   }
 }