diff --git a/identity/aidl/default/WritableIdentityCredential.cpp b/identity/aidl/default/WritableIdentityCredential.cpp
index ba2062d..89f7f35 100644
--- a/identity/aidl/default/WritableIdentityCredential.cpp
+++ b/identity/aidl/default/WritableIdentityCredential.cpp
@@ -16,6 +16,9 @@
 
 #define LOG_TAG "WritableIdentityCredential"
 
+#include "WritableIdentityCredential.h"
+#include "IdentityCredentialStore.h"
+
 #include <android/hardware/identity/support/IdentityCredentialSupport.h>
 
 #include <android-base/logging.h>
@@ -23,6 +26,8 @@
 #include <cppbor/cppbor.h>
 #include <cppbor/cppbor_parse.h>
 
+#include <utility>
+
 #include "IdentityCredentialStore.h"
 #include "Util.h"
 #include "WritableIdentityCredential.h"
@@ -33,26 +38,6 @@
 using namespace ::android::hardware::identity;
 
 bool WritableIdentityCredential::initialize() {
-    optional<vector<uint8_t>> keyPair = support::createEcKeyPair();
-    if (!keyPair) {
-        LOG(ERROR) << "Error creating credentialKey";
-        return false;
-    }
-
-    optional<vector<uint8_t>> pubKey = support::ecKeyPairGetPublicKey(keyPair.value());
-    if (!pubKey) {
-        LOG(ERROR) << "Error getting public part of credentialKey";
-        return false;
-    }
-    credentialPubKey_ = pubKey.value();
-
-    optional<vector<uint8_t>> privKey = support::ecKeyPairGetPrivateKey(keyPair.value());
-    if (!privKey) {
-        LOG(ERROR) << "Error getting private part of credentialKey";
-        return false;
-    }
-    credentialPrivKey_ = privKey.value();
-
     optional<vector<uint8_t>> random = support::getRandom(16);
     if (!random) {
         LOG(ERROR) << "Error creating storageKey";
@@ -63,88 +48,54 @@
     return true;
 }
 
-// TODO: use |attestationApplicationId| and |attestationChallenge| and also
-//       ensure the returned certificate chain satisfy the requirements listed in
-//       the docs for IWritableIdentityCredential::getAttestationCertificate()
-//
+// This function generates the attestation certificate using the passed in
+// |attestationApplicationId| and |attestationChallenge|.  It will generate an
+// 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*/, vector<Certificate>* outCertificateChain) {
-    // For now, we dynamically generate an attestion key on each and every
-    // request and use that to sign CredentialKey. In a real implementation this
-    // would look very differently.
-    optional<vector<uint8_t>> attestationKeyPair = support::createEcKeyPair();
-    if (!attestationKeyPair) {
-        return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
-                IIdentityCredentialStore::STATUS_FAILED, "Error creating attestationKey"));
-    }
-
-    optional<vector<uint8_t>> attestationPubKey =
-            support::ecKeyPairGetPublicKey(attestationKeyPair.value());
-    if (!attestationPubKey) {
+        const vector<int8_t>& attestationApplicationId,  //
+        const vector<int8_t>& attestationChallenge,      //
+        vector<Certificate>* outCertificateChain) {
+    if (!credentialPrivKey_.empty() || !credentialPubKey_.empty() || !certificateChain_.empty()) {
         return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
                 IIdentityCredentialStore::STATUS_FAILED,
-                "Error getting public part of attestationKey"));
+                "Error attestation certificate previously generated"));
     }
 
-    optional<vector<uint8_t>> attestationPrivKey =
-            support::ecKeyPairGetPrivateKey(attestationKeyPair.value());
-    if (!attestationPrivKey) {
+    vector<uint8_t> challenge(attestationChallenge.begin(), attestationChallenge.end());
+    vector<uint8_t> appId(attestationApplicationId.begin(), attestationApplicationId.end());
+
+    optional<std::pair<vector<uint8_t>, vector<vector<uint8_t>>>> keyAttestationPair =
+            support::createEcKeyPairAndAttestation(challenge, appId);
+    if (!keyAttestationPair) {
+        LOG(ERROR) << "Error creating credentialKey and attestation";
         return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
                 IIdentityCredentialStore::STATUS_FAILED,
-                "Error getting private part of attestationKey"));
+                "Error creating credentialKey and attestation"));
     }
 
-    string serialDecimal;
-    string issuer;
-    string subject;
-    time_t validityNotBefore = time(nullptr);
-    time_t validityNotAfter = validityNotBefore + 365 * 24 * 3600;
+    vector<uint8_t> keyPair = keyAttestationPair.value().first;
+    certificateChain_ = keyAttestationPair.value().second;
 
-    // First create a certificate for |credentialPubKey| which is signed by
-    // |attestationPrivKey|.
-    //
-    serialDecimal = "0";  // TODO: set serial to |attestationChallenge|
-    issuer = "Android Open Source Project";
-    subject = "Android IdentityCredential CredentialKey";
-    optional<vector<uint8_t>> credentialPubKeyCertificate = support::ecPublicKeyGenerateCertificate(
-            credentialPubKey_, attestationPrivKey.value(), serialDecimal, issuer, subject,
-            validityNotBefore, validityNotAfter);
-    if (!credentialPubKeyCertificate) {
+    optional<vector<uint8_t>> pubKey = support::ecKeyPairGetPublicKey(keyPair);
+    if (!pubKey) {
         return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
                 IIdentityCredentialStore::STATUS_FAILED,
-                "Error creating certificate for credentialPubKey"));
+                "Error getting public part of credentialKey"));
     }
+    credentialPubKey_ = pubKey.value();
 
-    // This is followed by a certificate for |attestationPubKey| self-signed by
-    // |attestationPrivKey|.
-    serialDecimal = "0";  // TODO: set serial
-    issuer = "Android Open Source Project";
-    subject = "Android IdentityCredential AttestationKey";
-    optional<vector<uint8_t>> attestationKeyCertificate = support::ecPublicKeyGenerateCertificate(
-            attestationPubKey.value(), attestationPrivKey.value(), serialDecimal, issuer, subject,
-            validityNotBefore, validityNotAfter);
-    if (!attestationKeyCertificate) {
+    optional<vector<uint8_t>> privKey = support::ecKeyPairGetPrivateKey(keyPair);
+    if (!privKey) {
         return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
                 IIdentityCredentialStore::STATUS_FAILED,
-                "Error creating certificate for attestationPubKey"));
+                "Error getting private part of credentialKey"));
     }
+    credentialPrivKey_ = privKey.value();
 
-    // Concatenate the certificates to form the chain.
-    vector<uint8_t> certificateChain;
-    certificateChain.insert(certificateChain.end(), credentialPubKeyCertificate.value().begin(),
-                            credentialPubKeyCertificate.value().end());
-    certificateChain.insert(certificateChain.end(), attestationKeyCertificate.value().begin(),
-                            attestationKeyCertificate.value().end());
-
-    optional<vector<vector<uint8_t>>> splitCertChain =
-            support::certificateChainSplit(certificateChain);
-    if (!splitCertChain) {
-        return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
-                IIdentityCredentialStore::STATUS_FAILED, "Error splitting certificate chain"));
-    }
+    // convert from vector<vector<uint8_t>>> to vector<Certificate>*
     *outCertificateChain = vector<Certificate>();
-    for (const vector<uint8_t>& cert : splitCertChain.value()) {
+    for (const vector<uint8_t>& cert : certificateChain_) {
         Certificate c = Certificate();
         c.encodedCertificate = byteStringToSigned(cert);
         outCertificateChain->push_back(std::move(c));
diff --git a/identity/aidl/default/WritableIdentityCredential.h b/identity/aidl/default/WritableIdentityCredential.h
index b380f89..b182862 100644
--- a/identity/aidl/default/WritableIdentityCredential.h
+++ b/identity/aidl/default/WritableIdentityCredential.h
@@ -64,10 +64,13 @@
     string docType_;
     bool testCredential_;
 
-    // These are set in initialize().
+    // This is set in initialize().
     vector<uint8_t> storageKey_;
+
+    // These are set in getAttestationCertificate().
     vector<uint8_t> credentialPrivKey_;
     vector<uint8_t> credentialPubKey_;
+    vector<vector<uint8_t>> certificateChain_;
 
     // These fields are initialized during startPersonalization()
     size_t numAccessControlProfileRemaining_;
diff --git a/identity/support/Android.bp b/identity/support/Android.bp
index 7b4546b..2b6c695 100644
--- a/identity/support/Android.bp
+++ b/identity/support/Android.bp
@@ -23,10 +23,14 @@
         "include",
     ],
     shared_libs: [
+        "android.hardware.keymaster@4.0",
         "libcrypto",
         "libbase",
         "libhidlbase",
         "libhardware",
+        "libkeymaster_portable",
+        "libsoft_attestation_cert",
+        "libpuresoftkeymasterdevice",
     ],
     static_libs: [
         "libcppbor",
diff --git a/identity/support/include/android/hardware/identity/support/IdentityCredentialSupport.h b/identity/support/include/android/hardware/identity/support/IdentityCredentialSupport.h
index 4533ad9..507e914 100644
--- a/identity/support/include/android/hardware/identity/support/IdentityCredentialSupport.h
+++ b/identity/support/include/android/hardware/identity/support/IdentityCredentialSupport.h
@@ -21,6 +21,7 @@
 #include <optional>
 #include <string>
 #include <tuple>
+#include <utility>
 #include <vector>
 
 namespace android {
@@ -106,6 +107,17 @@
 // ---------------------------------------------------------------------------
 // EC crypto functionality / abstraction (only supports P-256).
 // ---------------------------------------------------------------------------
+// Creates an 256-bit EC key using the NID_X9_62_prime256v1 curve, returns the
+// PKCS#8 encoded key-pair.  Also generates an attestation
+// certificate using the |challenge| and |applicationId|, and returns the generated
+// certificate in X.509 certificate chain format.
+//
+// The attestation time fields used will be the current time, and expires in one year.
+//
+// The first parameter of the return value is the keyPair generated, second return in
+// the pair is the attestation certificate generated.
+optional<std::pair<vector<uint8_t>, vector<vector<uint8_t>>>> createEcKeyPairAndAttestation(
+        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.
diff --git a/identity/support/src/IdentityCredentialSupport.cpp b/identity/support/src/IdentityCredentialSupport.cpp
index e2828bf..bf6a5c3 100644
--- a/identity/support/src/IdentityCredentialSupport.cpp
+++ b/identity/support/src/IdentityCredentialSupport.cpp
@@ -47,6 +47,13 @@
 #include <cppbor.h>
 #include <cppbor_parse.h>
 
+#include <android/hardware/keymaster/4.0/types.h>
+#include <keymaster/authorization_set.h>
+#include <keymaster/contexts/pure_soft_keymaster_context.h>
+#include <keymaster/contexts/soft_attestation_cert.h>
+#include <keymaster/keymaster_tags.h>
+#include <keymaster/km_openssl/attestation_utils.h>
+
 namespace android {
 namespace hardware {
 namespace identity {
@@ -816,6 +823,138 @@
     return hmac;
 }
 
+// Generates the attestation certificate with the parameters passed in.  Note
+// that the passed in |activeTimeMilliSeconds| |expireTimeMilliSeconds| are in
+// milli seconds since epoch.  We are setting them to milliseconds due to
+// requirement in AuthorizationSet KM_DATE fields.  The certificate created is
+// actually in seconds.
+optional<vector<vector<uint8_t>>> createAttestation(const EVP_PKEY* key,
+                                                    const vector<uint8_t>& applicationId,
+                                                    const vector<uint8_t>& challenge,
+                                                    uint64_t activeTimeMilliSeconds,
+                                                    uint64_t expireTimeMilliSeconds) {
+    ::keymaster::AuthorizationSet auth_set(
+            ::keymaster::AuthorizationSetBuilder()
+                    .Authorization(::keymaster::TAG_ATTESTATION_CHALLENGE, challenge.data(),
+                                   challenge.size())
+                    .Authorization(::keymaster::TAG_ACTIVE_DATETIME, activeTimeMilliSeconds)
+                    // Even though identity attestation hal said the application
+                    // id should be in software enforced authentication set,
+                    // keymaster portable lib expect the input in this
+                    // parameter because the software enforced in input to keymaster
+                    // refers to the key software enforced properties. And this
+                    // parameter refers to properties of the attestation which
+                    // includes app id.
+                    .Authorization(::keymaster::TAG_ATTESTATION_APPLICATION_ID,
+                                   applicationId.data(), applicationId.size())
+                    .Authorization(::keymaster::TAG_USAGE_EXPIRE_DATETIME, expireTimeMilliSeconds));
+
+    // Unique id and device id is not applicable for identity credential attestation,
+    // so we don't need to set those or application id.
+    ::keymaster::AuthorizationSet swEnforced(::keymaster::AuthorizationSetBuilder().Authorization(
+            ::keymaster::TAG_CREATION_DATETIME, activeTimeMilliSeconds));
+
+    ::keymaster::AuthorizationSet hwEnforced(
+            ::keymaster::AuthorizationSetBuilder()
+                    .Authorization(::keymaster::TAG_PURPOSE, KM_PURPOSE_SIGN)
+                    .Authorization(::keymaster::TAG_KEY_SIZE, 256)
+                    .Authorization(::keymaster::TAG_ALGORITHM, KM_ALGORITHM_EC)
+                    .Authorization(::keymaster::TAG_NO_AUTH_REQUIRED)
+                    .Authorization(::keymaster::TAG_DIGEST, KM_DIGEST_SHA_2_256)
+                    .Authorization(::keymaster::TAG_EC_CURVE, KM_EC_CURVE_P_256)
+                    .Authorization(::keymaster::TAG_IDENTITY_CREDENTIAL_KEY));
+
+    const keymaster_cert_chain_t* attestation_chain =
+            ::keymaster::getAttestationChain(KM_ALGORITHM_EC, nullptr);
+
+    if (attestation_chain == nullptr) {
+        LOG(ERROR) << "Error getting attestation chain";
+        return {};
+    }
+
+    const keymaster_key_blob_t* attestation_signing_key =
+            ::keymaster::getAttestationKey(KM_ALGORITHM_EC, nullptr);
+    if (attestation_signing_key == nullptr) {
+        LOG(ERROR) << "Error getting attestation key";
+        return {};
+    }
+
+    keymaster_error_t error;
+    ::keymaster::CertChainPtr cert_chain_out;
+    ::keymaster::PureSoftKeymasterContext context;
+
+    // set identity version to 10 per hal requirements specified in IWriteableCredential.hal
+    // For now, the identity version in the attestation is set in the keymaster
+    // version field in the portable keymaster lib, which is a bit misleading.
+    uint identity_version = 10;
+    error = generate_attestation_from_EVP(key, swEnforced, hwEnforced, auth_set, context,
+                                          identity_version, *attestation_chain,
+                                          *attestation_signing_key, &cert_chain_out);
+
+    if (KM_ERROR_OK != error || !cert_chain_out) {
+        LOG(ERROR) << "Error generate attestation from EVP key" << error;
+        return {};
+    }
+
+    // translate certificate format from keymaster_cert_chain_t to vector<uint8_t>.
+    vector<vector<uint8_t>> attestationCertificate;
+    for (int i = 0; i < cert_chain_out->entry_count; i++) {
+        attestationCertificate.insert(
+                attestationCertificate.end(),
+                vector<uint8_t>(
+                        cert_chain_out->entries[i].data,
+                        cert_chain_out->entries[i].data + cert_chain_out->entries[i].data_length));
+    }
+
+    return attestationCertificate;
+}
+
+optional<std::pair<vector<uint8_t>, vector<vector<uint8_t>>>> createEcKeyPairAndAttestation(
+        const vector<uint8_t>& challenge, const vector<uint8_t>& applicationId) {
+    auto ec_key = ::keymaster::EC_KEY_Ptr(EC_KEY_new());
+    auto pkey = ::keymaster::EVP_PKEY_Ptr(EVP_PKEY_new());
+    auto group = ::keymaster::EC_GROUP_Ptr(EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1));
+
+    if (ec_key.get() == nullptr || pkey.get() == nullptr) {
+        LOG(ERROR) << "Memory allocation failed";
+        return {};
+    }
+
+    if (EC_KEY_set_group(ec_key.get(), group.get()) != 1 ||
+        EC_KEY_generate_key(ec_key.get()) != 1 || EC_KEY_check_key(ec_key.get()) < 0) {
+        LOG(ERROR) << "Error generating key";
+        return {};
+    }
+
+    if (EVP_PKEY_set1_EC_KEY(pkey.get(), ec_key.get()) != 1) {
+        LOG(ERROR) << "Error getting private key";
+        return {};
+    }
+
+    uint64_t now = time(nullptr);
+    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 {};
+    }
+
+    int size = i2d_PrivateKey(pkey.get(), nullptr);
+    if (size == 0) {
+        LOG(ERROR) << "Error generating public key encoding";
+        return {};
+    }
+
+    vector<uint8_t> keyPair(size);
+    unsigned char* p = keyPair.data();
+    i2d_PrivateKey(pkey.get(), &p);
+
+    return make_pair(keyPair, attestationCert.value());
+}
+
 optional<vector<uint8_t>> createEcKeyPair() {
     auto ec_key = EC_KEY_Ptr(EC_KEY_new());
     auto pkey = EVP_PKEY_Ptr(EVP_PKEY_new());