Merge "Add server library build rules for both host and target" into rvc-dev
diff --git a/camera/device/3.2/ICameraDeviceCallback.hal b/camera/device/3.2/ICameraDeviceCallback.hal
index 607502e..206a649 100644
--- a/camera/device/3.2/ICameraDeviceCallback.hal
+++ b/camera/device/3.2/ICameraDeviceCallback.hal
@@ -87,8 +87,11 @@
      * ERROR_RESULT message.
      *
      * If an output buffer cannot be filled, its status field must be set to
-     * STATUS_ERROR. In addition, notify() must be called with a ERROR_BUFFER
-     * message.
+     * STATUS_ERROR. In this case, notify() isn't required to be called with
+     * an ERROR_BUFFER message. The framework will simply treat the notify()
+     * call with ERROR_BUFFER as a no-op, and derive whether and when to notify
+     * the application of buffer loss based on the buffer status and whether or not
+     * the entire capture has failed.
      *
      * If the entire capture has failed, then this method still needs to be
      * called to return the output buffers to the framework. All the buffer
diff --git a/current.txt b/current.txt
index 2608b54..b03d330 100644
--- a/current.txt
+++ b/current.txt
@@ -588,7 +588,7 @@
 578f640c653726d58f99c84a7e1bb63862e21ef7cbb4f7d95c3cc62de00dca35 android.hardware.automotive.evs@1.0::IEvsDisplay
 f5bc6aa840db933cb9fd36668b06d3e2021cf5384bb70e459f22e2f2f921fba5 android.hardware.automotive.evs@1.0::IEvsEnumerator
 d3a344b7bd4c0d2658ae7209f55a979b8f53f361fd00f4fca29d5baa56d11fd2 android.hardware.automotive.evs@1.0::types
-d123013165a19b6353cdc46a57b2ff4a17179619d36dbd595dfcf15dcd099af6 android.hardware.camera.device@3.2::ICameraDeviceCallback # b/155353799
+2924c3e43858190ee3e2da4c2fb93bba8ae065fe314451f035a7ec52cb80c94a android.hardware.camera.device@3.2::ICameraDeviceCallback # b/155353799
 2410dd02d67786a732d36e80b0f8ccf55086604ef37f9838e2013ff2c571e404 android.hardware.camera.device@3.5::types
 cd06a7911b9acd4a653bbf7133888878fbcb3f84be177c7a3f1becaae3d8618f android.hardware.camera.metadata@3.2::types
 5cf81b1001296fbb3c5b3d275a859244f61cec5fa858d7be9cca46c5b7dfa733 android.hardware.camera.metadata@3.2::types # b/150331548
diff --git a/identity/aidl/vts/Android.bp b/identity/aidl/vts/Android.bp
index cd6f9b0..c1f44e7 100644
--- a/identity/aidl/vts/Android.bp
+++ b/identity/aidl/vts/Android.bp
@@ -14,19 +14,19 @@
         "ReaderAuthTests.cpp",
     ],
     shared_libs: [
-        "android.hardware.keymaster@4.0",
         "libbinder",
         "libcrypto",
-        "android.hardware.keymaster-ndk_platform",
     ],
     static_libs: [
         "libcppbor",
         "libkeymaster_portable",
         "libsoft_attestation_cert",
         "libpuresoftkeymasterdevice",
+        "android.hardware.keymaster@4.0",
         "android.hardware.identity-support-lib",
         "android.hardware.identity-cpp",
         "android.hardware.keymaster-cpp",
+        "android.hardware.keymaster-ndk_platform",
     ],
     test_suites: [
         "general-tests",
diff --git a/identity/support/include/android/hardware/identity/support/IdentityCredentialSupport.h b/identity/support/include/android/hardware/identity/support/IdentityCredentialSupport.h
index 0f27a72..f7ec7c5 100644
--- a/identity/support/include/android/hardware/identity/support/IdentityCredentialSupport.h
+++ b/identity/support/include/android/hardware/identity/support/IdentityCredentialSupport.h
@@ -33,6 +33,7 @@
 using ::std::string;
 using ::std::tuple;
 using ::std::vector;
+using ::std::pair;
 
 // ---------------------------------------------------------------------------
 // Miscellaneous utilities.
@@ -119,6 +120,12 @@
 optional<std::pair<vector<uint8_t>, vector<vector<uint8_t>>>> createEcKeyPairAndAttestation(
         const vector<uint8_t>& challenge, const vector<uint8_t>& applicationId);
 
+// Like createEcKeyPairAndAttestation() but allows you to choose the public key.
+//
+optional<vector<vector<uint8_t>>> createAttestationForEcPublicKey(
+        const vector<uint8_t>& publicKey, const vector<uint8_t>& challenge,
+        const vector<uint8_t>& applicationId);
+
 // Creates an 256-bit EC key using the NID_X9_62_prime256v1 curve, returns the
 // PKCS#8 encoded key-pair.
 //
@@ -155,6 +162,12 @@
 //
 optional<vector<uint8_t>> signEcDsa(const vector<uint8_t>& key, const vector<uint8_t>& data);
 
+// Like signEcDsa() but instead of taking the data to be signed, takes a digest
+// of it instead.
+//
+optional<vector<uint8_t>> signEcDsaDigest(const vector<uint8_t>& key,
+                                          const vector<uint8_t>& dataDigest);
+
 // Calculates the HMAC with SHA-256 for |data| using |key|. The calculated HMAC
 // is returned and will be 32 bytes.
 //
@@ -175,6 +188,27 @@
 //
 optional<vector<uint8_t>> certificateChainGetTopMostKey(const vector<uint8_t>& certificateChain);
 
+// Extracts the public-key from the top-most certificate in |certificateChain|
+// (which should be a concatenated chain of DER-encoded X.509 certificates).
+//
+// Return offset and size of the public-key
+//
+optional<pair<size_t, size_t>> certificateFindPublicKey(const vector<uint8_t>& x509Certificate);
+
+// Extracts the TbsCertificate from the top-most certificate in |certificateChain|
+// (which should be a concatenated chain of DER-encoded X.509 certificates).
+//
+// Return offset and size of the TbsCertificate
+//
+optional<pair<size_t, size_t>> certificateTbsCertificate(const vector<uint8_t>& x509Certificate);
+
+// Extracts the Signature from the top-most certificate in |certificateChain|
+// (which should be a concatenated chain of DER-encoded X.509 certificates).
+//
+// Return offset and size of the Signature
+//
+optional<pair<size_t, size_t>> certificateFindSignature(const vector<uint8_t>& x509Certificate);
+
 // Generates a X.509 certificate for |publicKey| (which must be in the format
 // returned by ecKeyPairGetPublicKey()).
 //
@@ -231,6 +265,11 @@
 //
 bool certificateChainValidate(const vector<uint8_t>& certificateChain);
 
+// Returns true if |certificate| is signed by |publicKey|.
+//
+bool certificateSignedByPublicKey(const vector<uint8_t>& certificate,
+                                  const vector<uint8_t>& publicKey);
+
 // Signs |data| and |detachedContent| with |key| (which must be in the format
 // returned by ecKeyPairGetPrivateKey()).
 //
@@ -243,6 +282,21 @@
                                         const vector<uint8_t>& detachedContent,
                                         const vector<uint8_t>& certificateChain);
 
+// Creates a COSE_Signature1 where |signatureToBeSigned| is the ECDSA signature
+// of the ToBeSigned CBOR from RFC 8051 "4.4. Signing and Verification Process".
+//
+// The |signatureToBeSigned| is expected to be 64 bytes and contain the R value,
+// then the S value.
+//
+// The |data| parameter will be included in the COSE_Sign1 CBOR.
+//
+// If |certificateChain| is non-empty it's included in the 'x5chain'
+// protected header element (as as described in'draft-ietf-cose-x509-04').
+//
+optional<vector<uint8_t>> coseSignEcDsaWithSignature(const vector<uint8_t>& signatureToBeSigned,
+                                                     const vector<uint8_t>& data,
+                                                     const vector<uint8_t>& certificateChain);
+
 // Checks that |signatureCoseSign1| (in COSE_Sign1 format) is a valid signature
 // made with |public_key| (which must be in the format returned by
 // ecKeyPairGetPublicKey()) where |detachedContent| is the detached content.
@@ -251,9 +305,23 @@
                              const vector<uint8_t>& detachedContent,
                              const vector<uint8_t>& publicKey);
 
+// Converts a DER-encoded signature to the format used in 'signature' bstr in COSE_Sign1.
+bool ecdsaSignatureDerToCose(const vector<uint8_t>& ecdsaDerSignature,
+                             vector<uint8_t>& ecdsaCoseSignature);
+
+// Converts from the format in in 'signature' bstr in COSE_Sign1 to DER encoding.
+bool ecdsaSignatureCoseToDer(const vector<uint8_t>& ecdsaCoseSignature,
+                             vector<uint8_t>& ecdsaDerSignature);
+
 // Extracts the payload from a COSE_Sign1.
 optional<vector<uint8_t>> coseSignGetPayload(const vector<uint8_t>& signatureCoseSign1);
 
+// Extracts the signature (of the ToBeSigned CBOR) from a COSE_Sign1.
+optional<vector<uint8_t>> coseSignGetSignature(const vector<uint8_t>& signatureCoseSign1);
+
+// Extracts the signature algorithm from a COSE_Sign1.
+optional<int> coseSignGetAlg(const vector<uint8_t>& signatureCoseSign1);
+
 // Extracts the X.509 certificate chain, if present. Returns the data as a
 // concatenated chain of DER-encoded X.509 certificates
 //
@@ -269,6 +337,16 @@
 optional<vector<uint8_t>> coseMac0(const vector<uint8_t>& key, const vector<uint8_t>& data,
                                    const vector<uint8_t>& detachedContent);
 
+// Creates a COSE_Mac0 where |digestToBeMaced| is the HMAC-SHA256
+// of the ToBeMaced CBOR from RFC 8051 "6.3. How to Compute and Verify a MAC".
+//
+// The |digestToBeMaced| is expected to be 32 bytes.
+//
+// The |data| parameter will be included in the COSE_Mac0 CBOR.
+//
+optional<vector<uint8_t>> coseMacWithDigest(const vector<uint8_t>& digestToBeMaced,
+                                            const vector<uint8_t>& data);
+
 // ---------------------------------------------------------------------------
 // Utility functions specific to IdentityCredential.
 // ---------------------------------------------------------------------------
diff --git a/identity/support/src/IdentityCredentialSupport.cpp b/identity/support/src/IdentityCredentialSupport.cpp
index e9d5d6c..8e099e7 100644
--- a/identity/support/src/IdentityCredentialSupport.cpp
+++ b/identity/support/src/IdentityCredentialSupport.cpp
@@ -24,6 +24,7 @@
 #include <stdarg.h>
 #include <stdio.h>
 #include <time.h>
+#include <chrono>
 #include <iomanip>
 
 #include <openssl/aes.h>
@@ -684,6 +685,48 @@
     return true;
 }
 
+bool certificateSignedByPublicKey(const vector<uint8_t>& certificate,
+                                  const vector<uint8_t>& publicKey) {
+    const unsigned char* p = certificate.data();
+    auto x509 = X509_Ptr(d2i_X509(nullptr, &p, certificate.size()));
+    if (x509 == nullptr) {
+        LOG(ERROR) << "Error parsing X509 certificate";
+        return false;
+    }
+
+    auto group = EC_GROUP_Ptr(EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1));
+    auto point = EC_POINT_Ptr(EC_POINT_new(group.get()));
+    if (EC_POINT_oct2point(group.get(), point.get(), publicKey.data(), publicKey.size(), nullptr) !=
+        1) {
+        LOG(ERROR) << "Error decoding publicKey";
+        return false;
+    }
+    auto ecKey = EC_KEY_Ptr(EC_KEY_new());
+    auto pkey = EVP_PKEY_Ptr(EVP_PKEY_new());
+    if (ecKey.get() == nullptr || pkey.get() == nullptr) {
+        LOG(ERROR) << "Memory allocation failed";
+        return false;
+    }
+    if (EC_KEY_set_group(ecKey.get(), group.get()) != 1) {
+        LOG(ERROR) << "Error setting group";
+        return false;
+    }
+    if (EC_KEY_set_public_key(ecKey.get(), point.get()) != 1) {
+        LOG(ERROR) << "Error setting point";
+        return false;
+    }
+    if (EVP_PKEY_set1_EC_KEY(pkey.get(), ecKey.get()) != 1) {
+        LOG(ERROR) << "Error setting key";
+        return false;
+    }
+
+    if (X509_verify(x509.get(), pkey.get()) != 1) {
+        return false;
+    }
+
+    return true;
+}
+
 // TODO: Right now the only check we perform is to check that each certificate
 //       is signed by its successor. We should - but currently don't - also check
 //       things like valid dates etc.
@@ -770,7 +813,8 @@
     return ret;
 }
 
-optional<vector<uint8_t>> signEcDsa(const vector<uint8_t>& key, const vector<uint8_t>& data) {
+optional<vector<uint8_t>> signEcDsaDigest(const vector<uint8_t>& key,
+                                          const vector<uint8_t>& dataDigest) {
     auto bn = BIGNUM_Ptr(BN_bin2bn(key.data(), key.size(), nullptr));
     if (bn.get() == nullptr) {
         LOG(ERROR) << "Error creating BIGNUM";
@@ -783,8 +827,7 @@
         return {};
     }
 
-    auto digest = sha256(data);
-    ECDSA_SIG* sig = ECDSA_do_sign(digest.data(), digest.size(), ec_key.get());
+    ECDSA_SIG* sig = ECDSA_do_sign(dataDigest.data(), dataDigest.size(), ec_key.get());
     if (sig == nullptr) {
         LOG(ERROR) << "Error signing digest";
         return {};
@@ -798,6 +841,10 @@
     return signature;
 }
 
+optional<vector<uint8_t>> signEcDsa(const vector<uint8_t>& key, const vector<uint8_t>& data) {
+    return signEcDsaDigest(key, sha256(data));
+}
+
 optional<vector<uint8_t>> hmacSha256(const vector<uint8_t>& key, const vector<uint8_t>& data) {
     HMAC_CTX ctx;
     HMAC_CTX_init(&ctx);
@@ -955,6 +1002,51 @@
     return make_pair(keyPair, attestationCert.value());
 }
 
+optional<vector<vector<uint8_t>>> createAttestationForEcPublicKey(
+        const vector<uint8_t>& publicKey, const vector<uint8_t>& challenge,
+        const vector<uint8_t>& applicationId) {
+    auto group = EC_GROUP_Ptr(EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1));
+    auto point = EC_POINT_Ptr(EC_POINT_new(group.get()));
+    if (EC_POINT_oct2point(group.get(), point.get(), publicKey.data(), publicKey.size(), nullptr) !=
+        1) {
+        LOG(ERROR) << "Error decoding publicKey";
+        return {};
+    }
+    auto ecKey = EC_KEY_Ptr(EC_KEY_new());
+    auto pkey = EVP_PKEY_Ptr(EVP_PKEY_new());
+    if (ecKey.get() == nullptr || pkey.get() == nullptr) {
+        LOG(ERROR) << "Memory allocation failed";
+        return {};
+    }
+    if (EC_KEY_set_group(ecKey.get(), group.get()) != 1) {
+        LOG(ERROR) << "Error setting group";
+        return {};
+    }
+    if (EC_KEY_set_public_key(ecKey.get(), point.get()) != 1) {
+        LOG(ERROR) << "Error setting point";
+        return {};
+    }
+    if (EVP_PKEY_set1_EC_KEY(pkey.get(), ecKey.get()) != 1) {
+        LOG(ERROR) << "Error setting key";
+        return {};
+    }
+
+    uint64_t now = (std::chrono::duration_cast<std::chrono::nanoseconds>(
+                    std::chrono::system_clock::now().time_since_epoch()).
+                    count()/ 1000000000);
+    uint64_t secondsInOneYear = 365 * 24 * 60 * 60;
+    uint64_t expireTimeMs = (now + secondsInOneYear) * 1000;
+
+    optional<vector<vector<uint8_t>>> attestationCert =
+            createAttestation(pkey.get(), applicationId, challenge, now * 1000, expireTimeMs);
+    if (!attestationCert) {
+        LOG(ERROR) << "Error create attestation from key and challenge";
+        return {};
+    }
+
+    return attestationCert.value();
+}
+
 optional<vector<uint8_t>> createEcKeyPair() {
     auto ec_key = EC_KEY_Ptr(EC_KEY_new());
     auto pkey = EVP_PKEY_Ptr(EVP_PKEY_new());
@@ -1477,6 +1569,120 @@
     return publicKey;
 }
 
+optional<pair<size_t, size_t>> certificateFindPublicKey(const vector<uint8_t>& x509Certificate) {
+    vector<X509_Ptr> certs;
+    if (!parseX509Certificates(x509Certificate, certs)) {
+        return {};
+    }
+    if (certs.size() < 1) {
+        LOG(ERROR) << "No certificates in chain";
+        return {};
+    }
+
+    auto pkey = EVP_PKEY_Ptr(X509_get_pubkey(certs[0].get()));
+    if (pkey.get() == nullptr) {
+        LOG(ERROR) << "No public key";
+        return {};
+    }
+
+    auto ecKey = EC_KEY_Ptr(EVP_PKEY_get1_EC_KEY(pkey.get()));
+    if (ecKey.get() == nullptr) {
+        LOG(ERROR) << "Failed getting EC key";
+        return {};
+    }
+
+    auto ecGroup = EC_KEY_get0_group(ecKey.get());
+    auto ecPoint = EC_KEY_get0_public_key(ecKey.get());
+    int size = EC_POINT_point2oct(ecGroup, ecPoint, POINT_CONVERSION_UNCOMPRESSED, nullptr, 0,
+                                  nullptr);
+    if (size == 0) {
+        LOG(ERROR) << "Error generating public key encoding";
+        return {};
+    }
+    vector<uint8_t> publicKey;
+    publicKey.resize(size);
+    EC_POINT_point2oct(ecGroup, ecPoint, POINT_CONVERSION_UNCOMPRESSED, publicKey.data(),
+                       publicKey.size(), nullptr);
+
+    size_t publicKeyOffset = 0;
+    size_t publicKeySize = (size_t)size;
+    void* location = memmem((const void*)x509Certificate.data(), x509Certificate.size(),
+                            (const void*)publicKey.data(), publicKey.size());
+
+    if (location == NULL) {
+        LOG(ERROR) << "Error finding publicKey from x509Certificate";
+        return {};
+    }
+    publicKeyOffset = (size_t)((const char*)location - (const char*)x509Certificate.data());
+
+    return std::make_pair(publicKeyOffset, publicKeySize);
+}
+
+optional<pair<size_t, size_t>> certificateTbsCertificate(const vector<uint8_t>& x509Certificate) {
+    vector<X509_Ptr> certs;
+    if (!parseX509Certificates(x509Certificate, certs)) {
+        return {};
+    }
+    if (certs.size() < 1) {
+        LOG(ERROR) << "No certificates in chain";
+        return {};
+    }
+
+    unsigned char* buf = NULL;
+    int len = i2d_re_X509_tbs(certs[0].get(), &buf);
+    if ((len < 0) || (buf == NULL)) {
+        LOG(ERROR) << "fail to extract tbsCertificate in x509Certificate";
+        return {};
+    }
+
+    vector<uint8_t> tbsCertificate(len);
+    memcpy(tbsCertificate.data(), buf, len);
+
+    size_t tbsCertificateOffset = 0;
+    size_t tbsCertificateSize = (size_t)len;
+    void* location = memmem((const void*)x509Certificate.data(), x509Certificate.size(),
+                            (const void*)tbsCertificate.data(), tbsCertificate.size());
+
+    if (location == NULL) {
+        LOG(ERROR) << "Error finding tbsCertificate from x509Certificate";
+        return {};
+    }
+    tbsCertificateOffset = (size_t)((const char*)location - (const char*)x509Certificate.data());
+
+    return std::make_pair(tbsCertificateOffset, tbsCertificateSize);
+}
+
+optional<pair<size_t, size_t>> certificateFindSignature(const vector<uint8_t>& x509Certificate) {
+    vector<X509_Ptr> certs;
+    if (!parseX509Certificates(x509Certificate, certs)) {
+        return {};
+    }
+    if (certs.size() < 1) {
+        LOG(ERROR) << "No certificates in chain";
+        return {};
+    }
+
+    ASN1_BIT_STRING* psig;
+    X509_ALGOR* palg;
+    X509_get0_signature((const ASN1_BIT_STRING**)&psig, (const X509_ALGOR**)&palg, certs[0].get());
+
+    vector<char> signature(psig->length);
+    memcpy(signature.data(), psig->data, psig->length);
+
+    size_t signatureOffset = 0;
+    size_t signatureSize = (size_t)psig->length;
+    void* location = memmem((const void*)x509Certificate.data(), x509Certificate.size(),
+                            (const void*)signature.data(), signature.size());
+
+    if (location == NULL) {
+        LOG(ERROR) << "Error finding signature from x509Certificate";
+        return {};
+    }
+    signatureOffset = (size_t)((const char*)location - (const char*)x509Certificate.data());
+
+    return std::make_pair(signatureOffset, signatureSize);
+}
+
 // ---------------------------------------------------------------------------
 // COSE Utility Functions
 // ---------------------------------------------------------------------------
@@ -1574,6 +1780,55 @@
     return true;
 }
 
+optional<vector<uint8_t>> coseSignEcDsaWithSignature(const vector<uint8_t>& signatureToBeSigned,
+                                                     const vector<uint8_t>& data,
+                                                     const vector<uint8_t>& certificateChain) {
+    if (signatureToBeSigned.size() != 64) {
+        LOG(ERROR) << "Invalid size for signatureToBeSigned, expected 64 got "
+                   << signatureToBeSigned.size();
+        return {};
+    }
+
+    cppbor::Map unprotectedHeaders;
+    cppbor::Map protectedHeaders;
+
+    protectedHeaders.add(COSE_LABEL_ALG, COSE_ALG_ECDSA_256);
+
+    if (certificateChain.size() != 0) {
+        optional<vector<vector<uint8_t>>> certs = support::certificateChainSplit(certificateChain);
+        if (!certs) {
+            LOG(ERROR) << "Error splitting certificate chain";
+            return {};
+        }
+        if (certs.value().size() == 1) {
+            unprotectedHeaders.add(COSE_LABEL_X5CHAIN, certs.value()[0]);
+        } else {
+            cppbor::Array certArray;
+            for (const vector<uint8_t>& cert : certs.value()) {
+                certArray.add(cert);
+            }
+            unprotectedHeaders.add(COSE_LABEL_X5CHAIN, std::move(certArray));
+        }
+    }
+
+    vector<uint8_t> encodedProtectedHeaders = coseEncodeHeaders(protectedHeaders);
+
+    cppbor::Array coseSign1;
+    coseSign1.add(encodedProtectedHeaders);
+    coseSign1.add(std::move(unprotectedHeaders));
+    if (data.size() == 0) {
+        cppbor::Null nullValue;
+        coseSign1.add(std::move(nullValue));
+    } else {
+        coseSign1.add(data);
+    }
+    coseSign1.add(signatureToBeSigned);
+    vector<uint8_t> signatureCoseSign1;
+    signatureCoseSign1 = coseSign1.encode();
+
+    return signatureCoseSign1;
+}
+
 optional<vector<uint8_t>> coseSignEcDsa(const vector<uint8_t>& key, const vector<uint8_t>& data,
                                         const vector<uint8_t>& detachedContent,
                                         const vector<uint8_t>& certificateChain) {
@@ -1709,6 +1964,35 @@
     return true;
 }
 
+// Extracts the signature (of the ToBeSigned CBOR) from a COSE_Sign1.
+optional<vector<uint8_t>> coseSignGetSignature(const vector<uint8_t>& signatureCoseSign1) {
+    auto [item, _, message] = cppbor::parse(signatureCoseSign1);
+    if (item == nullptr) {
+        LOG(ERROR) << "Passed-in COSE_Sign1 is not valid CBOR: " << message;
+        return {};
+    }
+    const cppbor::Array* array = item->asArray();
+    if (array == nullptr) {
+        LOG(ERROR) << "Value for COSE_Sign1 is not an array";
+        return {};
+    }
+    if (array->size() != 4) {
+        LOG(ERROR) << "Value for COSE_Sign1 is not an array of size 4";
+        return {};
+    }
+
+    vector<uint8_t> signature;
+    const cppbor::Bstr* signatureAsBstr = (*array)[3]->asBstr();
+    if (signatureAsBstr == nullptr) {
+        LOG(ERROR) << "Value for signature is not a bstr";
+        return {};
+    }
+    // Copy payload into |data|
+    signature = signatureAsBstr->value();
+
+    return signature;
+}
+
 optional<vector<uint8_t>> coseSignGetPayload(const vector<uint8_t>& signatureCoseSign1) {
     auto [item, _, message] = cppbor::parse(signatureCoseSign1);
     if (item == nullptr) {
@@ -1746,6 +2030,59 @@
     return data;
 }
 
+optional<int> coseSignGetAlg(const vector<uint8_t>& signatureCoseSign1) {
+    auto [item, _, message] = cppbor::parse(signatureCoseSign1);
+    if (item == nullptr) {
+        LOG(ERROR) << "Passed-in COSE_Sign1 is not valid CBOR: " << message;
+        return {};
+    }
+    const cppbor::Array* array = item->asArray();
+    if (array == nullptr) {
+        LOG(ERROR) << "Value for COSE_Sign1 is not an array";
+        return {};
+    }
+    if (array->size() != 4) {
+        LOG(ERROR) << "Value for COSE_Sign1 is not an array of size 4";
+        return {};
+    }
+
+    const cppbor::Bstr* protectedHeadersBytes = (*array)[0]->asBstr();
+    if (protectedHeadersBytes == nullptr) {
+        LOG(ERROR) << "Value for protectedHeaders is not a bstr";
+        return {};
+    }
+    auto [item2, _2, message2] = cppbor::parse(protectedHeadersBytes->value());
+    if (item2 == nullptr) {
+        LOG(ERROR) << "Error parsing protectedHeaders: " << message2;
+        return {};
+    }
+    const cppbor::Map* protectedHeaders = item2->asMap();
+    if (protectedHeaders == nullptr) {
+        LOG(ERROR) << "Decoded CBOR for protectedHeaders is not a map";
+        return {};
+    }
+
+    for (size_t n = 0; n < protectedHeaders->size(); n++) {
+        auto [keyItem, valueItem] = (*protectedHeaders)[n];
+        const cppbor::Int* number = keyItem->asInt();
+        if (number == nullptr) {
+            LOG(ERROR) << "Key item in top-level map is not a number";
+            return {};
+        }
+        int label = number->value();
+        if (label == COSE_LABEL_ALG) {
+            const cppbor::Int* number = valueItem->asInt();
+            if (number != nullptr) {
+                return number->value();
+            }
+            LOG(ERROR) << "Value for COSE_LABEL_ALG label is not a number";
+            return {};
+        }
+    }
+    LOG(ERROR) << "Did not find COSE_LABEL_ALG label in protected headers";
+    return {};
+}
+
 optional<vector<uint8_t>> coseSignGetX5Chain(const vector<uint8_t>& signatureCoseSign1) {
     auto [item, _, message] = cppbor::parse(signatureCoseSign1);
     if (item == nullptr) {
@@ -1861,6 +2198,28 @@
     return array.encode();
 }
 
+optional<vector<uint8_t>> coseMacWithDigest(const vector<uint8_t>& digestToBeMaced,
+                                            const vector<uint8_t>& data) {
+    cppbor::Map unprotectedHeaders;
+    cppbor::Map protectedHeaders;
+
+    protectedHeaders.add(COSE_LABEL_ALG, COSE_ALG_HMAC_256_256);
+
+    vector<uint8_t> encodedProtectedHeaders = coseEncodeHeaders(protectedHeaders);
+
+    cppbor::Array array;
+    array.add(encodedProtectedHeaders);
+    array.add(std::move(unprotectedHeaders));
+    if (data.size() == 0) {
+        cppbor::Null nullValue;
+        array.add(std::move(nullValue));
+    } else {
+        array.add(data);
+    }
+    array.add(digestToBeMaced);
+    return array.encode();
+}
+
 // ---------------------------------------------------------------------------
 // Utility functions specific to IdentityCredential.
 // ---------------------------------------------------------------------------