diff --git a/identity/aidl/default/IdentityCredential.cpp b/identity/aidl/default/IdentityCredential.cpp
index 341fae6..aaae1f6 100644
--- a/identity/aidl/default/IdentityCredential.cpp
+++ b/identity/aidl/default/IdentityCredential.cpp
@@ -102,7 +102,7 @@
 }
 
 ndk::ScopedAStatus IdentityCredential::deleteCredential(
-        vector<int8_t>* outProofOfDeletionSignature) {
+        vector<uint8_t>* outProofOfDeletionSignature) {
     cppbor::Array array = {"ProofOfDeletion", docType_, testCredential_};
     vector<uint8_t> proofOfDeletion = array.encode();
 
@@ -115,11 +115,11 @@
                 IIdentityCredentialStore::STATUS_FAILED, "Error signing data"));
     }
 
-    *outProofOfDeletionSignature = byteStringToSigned(signature.value());
+    *outProofOfDeletionSignature = signature.value();
     return ndk::ScopedAStatus::ok();
 }
 
-ndk::ScopedAStatus IdentityCredential::createEphemeralKeyPair(vector<int8_t>* outKeyPair) {
+ndk::ScopedAStatus IdentityCredential::createEphemeralKeyPair(vector<uint8_t>* outKeyPair) {
     optional<vector<uint8_t>> kp = support::createEcKeyPair();
     if (!kp) {
         return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
@@ -135,13 +135,13 @@
     }
     ephemeralPublicKey_ = publicKey.value();
 
-    *outKeyPair = byteStringToSigned(kp.value());
+    *outKeyPair = kp.value();
     return ndk::ScopedAStatus::ok();
 }
 
 ndk::ScopedAStatus IdentityCredential::setReaderEphemeralPublicKey(
-        const vector<int8_t>& publicKey) {
-    readerPublicKey_ = byteStringToUnsigned(publicKey);
+        const vector<uint8_t>& publicKey) {
+    readerPublicKey_ = publicKey;
     return ndk::ScopedAStatus::ok();
 }
 
@@ -169,8 +169,8 @@
 // ahead of time.
 bool checkReaderAuthentication(const SecureAccessControlProfile& profile,
                                const vector<uint8_t>& readerCertificateChain) {
-    optional<vector<uint8_t>> acpPubKey = support::certificateChainGetTopMostKey(
-            byteStringToUnsigned(profile.readerCertificate.encodedCertificate));
+    optional<vector<uint8_t>> acpPubKey =
+            support::certificateChainGetTopMostKey(profile.readerCertificate.encodedCertificate);
     if (!acpPubKey) {
         LOG(ERROR) << "Error extracting public key from readerCertificate in profile";
         return false;
@@ -255,13 +255,9 @@
 
 ndk::ScopedAStatus IdentityCredential::startRetrieval(
         const vector<SecureAccessControlProfile>& accessControlProfiles,
-        const HardwareAuthToken& authToken, const vector<int8_t>& itemsRequestS,
-        const vector<int8_t>& signingKeyBlobS, const vector<int8_t>& sessionTranscriptS,
-        const vector<int8_t>& readerSignatureS, const vector<int32_t>& requestCounts) {
-    auto sessionTranscript = byteStringToUnsigned(sessionTranscriptS);
-    auto itemsRequest = byteStringToUnsigned(itemsRequestS);
-    auto readerSignature = byteStringToUnsigned(readerSignatureS);
-
+        const HardwareAuthToken& authToken, const vector<uint8_t>& itemsRequest,
+        const vector<uint8_t>& signingKeyBlob, const vector<uint8_t>& sessionTranscript,
+        const vector<uint8_t>& readerSignature, const vector<int32_t>& requestCounts) {
     if (sessionTranscript.size() > 0) {
         auto [item, _, message] = cppbor::parse(sessionTranscript);
         if (item == nullptr) {
@@ -498,7 +494,7 @@
     currentNameSpace_ = "";
 
     itemsRequest_ = itemsRequest;
-    signingKeyBlob_ = byteStringToUnsigned(signingKeyBlobS);
+    signingKeyBlob_ = signingKeyBlob;
 
     numStartRetrievalCalls_ += 1;
     return ndk::ScopedAStatus::ok();
@@ -605,10 +601,8 @@
     return ndk::ScopedAStatus::ok();
 }
 
-ndk::ScopedAStatus IdentityCredential::retrieveEntryValue(const vector<int8_t>& encryptedContentS,
-                                                          vector<int8_t>* outContent) {
-    auto encryptedContent = byteStringToUnsigned(encryptedContentS);
-
+ndk::ScopedAStatus IdentityCredential::retrieveEntryValue(const vector<uint8_t>& encryptedContent,
+                                                          vector<uint8_t>* outContent) {
     optional<vector<uint8_t>> content =
             support::decryptAes128Gcm(storageKey_, encryptedContent, entryAdditionalData_);
     if (!content) {
@@ -647,12 +641,12 @@
         currentNameSpaceDeviceNameSpacesMap_.add(currentName_, std::move(entryValueItem));
     }
 
-    *outContent = byteStringToSigned(content.value());
+    *outContent = content.value();
     return ndk::ScopedAStatus::ok();
 }
 
-ndk::ScopedAStatus IdentityCredential::finishRetrieval(vector<int8_t>* outMac,
-                                                       vector<int8_t>* outDeviceNameSpaces) {
+ndk::ScopedAStatus IdentityCredential::finishRetrieval(vector<uint8_t>* outMac,
+                                                       vector<uint8_t>* outDeviceNameSpaces) {
     if (currentNameSpaceDeviceNameSpacesMap_.size() > 0) {
         deviceNameSpacesMap_.add(currentNameSpace_,
                                  std::move(currentNameSpaceDeviceNameSpacesMap_));
@@ -704,13 +698,13 @@
         }
     }
 
-    *outMac = byteStringToSigned(mac.value_or(vector<uint8_t>({})));
-    *outDeviceNameSpaces = byteStringToSigned(encodedDeviceNameSpaces);
+    *outMac = mac.value_or(vector<uint8_t>({}));
+    *outDeviceNameSpaces = encodedDeviceNameSpaces;
     return ndk::ScopedAStatus::ok();
 }
 
 ndk::ScopedAStatus IdentityCredential::generateSigningKeyPair(
-        vector<int8_t>* outSigningKeyBlob, Certificate* outSigningKeyCertificate) {
+        vector<uint8_t>* outSigningKeyBlob, Certificate* outSigningKeyCertificate) {
     string serialDecimal = "0";  // TODO: set serial to something unique
     string issuer = "Android Open Source Project";
     string subject = "Android IdentityCredential Reference Implementation";
@@ -758,9 +752,9 @@
         return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
                 IIdentityCredentialStore::STATUS_FAILED, "Error encrypting signingKey"));
     }
-    *outSigningKeyBlob = byteStringToSigned(encryptedSigningKey.value());
+    *outSigningKeyBlob = encryptedSigningKey.value();
     *outSigningKeyCertificate = Certificate();
-    outSigningKeyCertificate->encodedCertificate = byteStringToSigned(certificate.value());
+    outSigningKeyCertificate->encodedCertificate = certificate.value();
     return ndk::ScopedAStatus::ok();
 }
 
diff --git a/identity/aidl/default/IdentityCredential.h b/identity/aidl/default/IdentityCredential.h
index fc29254..6072afe 100644
--- a/identity/aidl/default/IdentityCredential.h
+++ b/identity/aidl/default/IdentityCredential.h
@@ -47,23 +47,23 @@
     int initialize();
 
     // Methods from IIdentityCredential follow.
-    ndk::ScopedAStatus deleteCredential(vector<int8_t>* outProofOfDeletionSignature) override;
-    ndk::ScopedAStatus createEphemeralKeyPair(vector<int8_t>* outKeyPair) override;
-    ndk::ScopedAStatus setReaderEphemeralPublicKey(const vector<int8_t>& publicKey) override;
+    ndk::ScopedAStatus deleteCredential(vector<uint8_t>* outProofOfDeletionSignature) override;
+    ndk::ScopedAStatus createEphemeralKeyPair(vector<uint8_t>* outKeyPair) override;
+    ndk::ScopedAStatus setReaderEphemeralPublicKey(const vector<uint8_t>& publicKey) override;
     ndk::ScopedAStatus createAuthChallenge(int64_t* outChallenge) override;
     ndk::ScopedAStatus startRetrieval(
             const vector<SecureAccessControlProfile>& accessControlProfiles,
-            const HardwareAuthToken& authToken, const vector<int8_t>& itemsRequest,
-            const vector<int8_t>& signingKeyBlob, const vector<int8_t>& sessionTranscript,
-            const vector<int8_t>& readerSignature, const vector<int32_t>& requestCounts) override;
+            const HardwareAuthToken& authToken, const vector<uint8_t>& itemsRequest,
+            const vector<uint8_t>& signingKeyBlob, const vector<uint8_t>& sessionTranscript,
+            const vector<uint8_t>& readerSignature, const vector<int32_t>& requestCounts) override;
     ndk::ScopedAStatus startRetrieveEntryValue(
             const string& nameSpace, const string& name, int32_t entrySize,
             const vector<int32_t>& accessControlProfileIds) override;
-    ndk::ScopedAStatus retrieveEntryValue(const vector<int8_t>& encryptedContent,
-                                          vector<int8_t>* outContent) override;
-    ndk::ScopedAStatus finishRetrieval(vector<int8_t>* outMac,
-                                       vector<int8_t>* outDeviceNameSpaces) override;
-    ndk::ScopedAStatus generateSigningKeyPair(vector<int8_t>* outSigningKeyBlob,
+    ndk::ScopedAStatus retrieveEntryValue(const vector<uint8_t>& encryptedContent,
+                                          vector<uint8_t>* outContent) override;
+    ndk::ScopedAStatus finishRetrieval(vector<uint8_t>* outMac,
+                                       vector<uint8_t>* outDeviceNameSpaces) override;
+    ndk::ScopedAStatus generateSigningKeyPair(vector<uint8_t>* outSigningKeyBlob,
                                               Certificate* outSigningKeyCertificate) override;
 
   private:
diff --git a/identity/aidl/default/IdentityCredentialStore.cpp b/identity/aidl/default/IdentityCredentialStore.cpp
index 1efb4b4..30dc6f3 100644
--- a/identity/aidl/default/IdentityCredentialStore.cpp
+++ b/identity/aidl/default/IdentityCredentialStore.cpp
@@ -51,7 +51,7 @@
 }
 
 ndk::ScopedAStatus IdentityCredentialStore::getCredential(
-        CipherSuite cipherSuite, const vector<int8_t>& credentialData,
+        CipherSuite cipherSuite, const vector<uint8_t>& credentialData,
         shared_ptr<IIdentityCredential>* outCredential) {
     // We only support CIPHERSUITE_ECDHE_HKDF_ECDSA_WITH_AES_256_GCM_SHA256 right now.
     if (cipherSuite != CipherSuite::CIPHERSUITE_ECDHE_HKDF_ECDSA_WITH_AES_256_GCM_SHA256) {
@@ -60,8 +60,8 @@
                 "Unsupported cipher suite"));
     }
 
-    vector<uint8_t> data = vector<uint8_t>(credentialData.begin(), credentialData.end());
-    shared_ptr<IdentityCredential> credential = ndk::SharedRefBase::make<IdentityCredential>(data);
+    shared_ptr<IdentityCredential> credential =
+            ndk::SharedRefBase::make<IdentityCredential>(credentialData);
     auto ret = credential->initialize();
     if (ret != IIdentityCredentialStore::STATUS_OK) {
         return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
diff --git a/identity/aidl/default/IdentityCredentialStore.h b/identity/aidl/default/IdentityCredentialStore.h
index a205113..4f3a421 100644
--- a/identity/aidl/default/IdentityCredentialStore.h
+++ b/identity/aidl/default/IdentityCredentialStore.h
@@ -39,7 +39,7 @@
             const string& docType, bool testCredential,
             shared_ptr<IWritableIdentityCredential>* outWritableCredential) override;
 
-    ndk::ScopedAStatus getCredential(CipherSuite cipherSuite, const vector<int8_t>& credentialData,
+    ndk::ScopedAStatus getCredential(CipherSuite cipherSuite, const vector<uint8_t>& credentialData,
                                      shared_ptr<IIdentityCredential>* outCredential) override;
 };
 
diff --git a/identity/aidl/default/Util.cpp b/identity/aidl/default/Util.cpp
index a0f86be..66b9f13 100644
--- a/identity/aidl/default/Util.cpp
+++ b/identity/aidl/default/Util.cpp
@@ -39,21 +39,12 @@
     return hardwareBoundKey;
 }
 
-vector<uint8_t> byteStringToUnsigned(const vector<int8_t>& value) {
-    return vector<uint8_t>(value.begin(), value.end());
-}
-
-vector<int8_t> byteStringToSigned(const vector<uint8_t>& value) {
-    return vector<int8_t>(value.begin(), value.end());
-}
-
 vector<uint8_t> secureAccessControlProfileEncodeCbor(const SecureAccessControlProfile& profile) {
     cppbor::Map map;
     map.add("id", profile.id);
 
     if (profile.readerCertificate.encodedCertificate.size() > 0) {
-        map.add("readerCertificate",
-                cppbor::Bstr(byteStringToUnsigned(profile.readerCertificate.encodedCertificate)));
+        map.add("readerCertificate", cppbor::Bstr(profile.readerCertificate.encodedCertificate));
     }
 
     if (profile.userAuthenticationRequired) {
@@ -94,7 +85,7 @@
     if (!mac) {
         return false;
     }
-    if (mac.value() != byteStringToUnsigned(profile.mac)) {
+    if (mac.value() != profile.mac) {
         return false;
     }
     return true;
diff --git a/identity/aidl/default/Util.h b/identity/aidl/default/Util.h
index ee41ad1..9fccba2 100644
--- a/identity/aidl/default/Util.h
+++ b/identity/aidl/default/Util.h
@@ -49,10 +49,6 @@
 vector<uint8_t> entryCreateAdditionalData(const string& nameSpace, const string& name,
                                           const vector<int32_t> accessControlProfileIds);
 
-vector<uint8_t> byteStringToUnsigned(const vector<int8_t>& value);
-
-vector<int8_t> byteStringToSigned(const vector<uint8_t>& value);
-
 }  // namespace aidl::android::hardware::identity
 
 #endif  // ANDROID_HARDWARE_IDENTITY_UTIL_H
diff --git a/identity/aidl/default/WritableIdentityCredential.cpp b/identity/aidl/default/WritableIdentityCredential.cpp
index 89f7f35..bce913a 100644
--- a/identity/aidl/default/WritableIdentityCredential.cpp
+++ b/identity/aidl/default/WritableIdentityCredential.cpp
@@ -53,8 +53,8 @@
 // attestation certificate with current time and expires one year from now.  The
 // certificate shall contain all values as specified in hal.
 ndk::ScopedAStatus WritableIdentityCredential::getAttestationCertificate(
-        const vector<int8_t>& attestationApplicationId,  //
-        const vector<int8_t>& attestationChallenge,      //
+        const vector<uint8_t>& attestationApplicationId,  //
+        const vector<uint8_t>& attestationChallenge,      //
         vector<Certificate>* outCertificateChain) {
     if (!credentialPrivKey_.empty() || !credentialPubKey_.empty() || !certificateChain_.empty()) {
         return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
@@ -97,7 +97,7 @@
     *outCertificateChain = vector<Certificate>();
     for (const vector<uint8_t>& cert : certificateChain_) {
         Certificate c = Certificate();
-        c.encodedCertificate = byteStringToSigned(cert);
+        c.encodedCertificate = cert;
         outCertificateChain->push_back(std::move(c));
     }
     return ndk::ScopedAStatus::ok();
@@ -146,14 +146,13 @@
         return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
                 IIdentityCredentialStore::STATUS_FAILED, "Error calculating MAC for profile"));
     }
-    profile.mac = byteStringToSigned(mac.value());
+    profile.mac = mac.value();
 
     cppbor::Map profileMap;
     profileMap.add("id", profile.id);
     if (profile.readerCertificate.encodedCertificate.size() > 0) {
-        profileMap.add(
-                "readerCertificate",
-                cppbor::Bstr(byteStringToUnsigned(profile.readerCertificate.encodedCertificate)));
+        profileMap.add("readerCertificate",
+                       cppbor::Bstr(profile.readerCertificate.encodedCertificate));
     }
     if (profile.userAuthenticationRequired) {
         profileMap.add("userAuthenticationRequired", profile.userAuthenticationRequired);
@@ -223,9 +222,8 @@
     return ndk::ScopedAStatus::ok();
 }
 
-ndk::ScopedAStatus WritableIdentityCredential::addEntryValue(const vector<int8_t>& contentS,
-                                                             vector<int8_t>* outEncryptedContent) {
-    auto content = byteStringToUnsigned(contentS);
+ndk::ScopedAStatus WritableIdentityCredential::addEntryValue(const vector<uint8_t>& content,
+                                                             vector<uint8_t>* outEncryptedContent) {
     size_t contentSize = content.size();
 
     if (contentSize > IdentityCredentialStore::kGcmChunkSize) {
@@ -280,7 +278,7 @@
         signedDataCurrentNamespace_.add(std::move(entryMap));
     }
 
-    *outEncryptedContent = byteStringToSigned(encryptedContent.value());
+    *outEncryptedContent = encryptedContent.value();
     return ndk::ScopedAStatus::ok();
 }
 
@@ -329,7 +327,7 @@
 }
 
 ndk::ScopedAStatus WritableIdentityCredential::finishAddingEntries(
-        vector<int8_t>* outCredentialData, vector<int8_t>* outProofOfProvisioningSignature) {
+        vector<uint8_t>* outCredentialData, vector<uint8_t>* outProofOfProvisioningSignature) {
     if (signedDataCurrentNamespace_.size() > 0) {
         signedDataNamespaces_.add(entryNameSpace_, std::move(signedDataCurrentNamespace_));
     }
@@ -364,8 +362,8 @@
                 IIdentityCredentialStore::STATUS_FAILED, "Error generating CredentialData"));
     }
 
-    *outCredentialData = byteStringToSigned(credentialData);
-    *outProofOfProvisioningSignature = byteStringToSigned(signature.value());
+    *outCredentialData = credentialData;
+    *outProofOfProvisioningSignature = signature.value();
     return ndk::ScopedAStatus::ok();
 }
 
diff --git a/identity/aidl/default/WritableIdentityCredential.h b/identity/aidl/default/WritableIdentityCredential.h
index b182862..4b6fca8 100644
--- a/identity/aidl/default/WritableIdentityCredential.h
+++ b/identity/aidl/default/WritableIdentityCredential.h
@@ -37,8 +37,8 @@
     bool initialize();
 
     // Methods from IWritableIdentityCredential follow.
-    ndk::ScopedAStatus getAttestationCertificate(const vector<int8_t>& attestationApplicationId,
-                                                 const vector<int8_t>& attestationChallenge,
+    ndk::ScopedAStatus getAttestationCertificate(const vector<uint8_t>& attestationApplicationId,
+                                                 const vector<uint8_t>& attestationChallenge,
                                                  vector<Certificate>* outCertificateChain) override;
 
     ndk::ScopedAStatus startPersonalization(int32_t accessControlProfileCount,
@@ -53,12 +53,12 @@
                                      const string& nameSpace, const string& name,
                                      int32_t entrySize) override;
 
-    ndk::ScopedAStatus addEntryValue(const vector<int8_t>& content,
-                                     vector<int8_t>* outEncryptedContent) override;
+    ndk::ScopedAStatus addEntryValue(const vector<uint8_t>& content,
+                                     vector<uint8_t>* outEncryptedContent) override;
 
     ndk::ScopedAStatus finishAddingEntries(
-            vector<int8_t>* outCredentialData,
-            vector<int8_t>* outProofOfProvisioningSignature) override;
+            vector<uint8_t>* outCredentialData,
+            vector<uint8_t>* outProofOfProvisioningSignature) override;
 
     // private:
     string docType_;