Examples with KeyProtection android.security.keystore.KeyProtection used on opensource projects

Example 11 with KeyProtection

use of android.security.keystore.KeyProtection in project android_frameworks_base by AOSPA.

the class AndroidKeyStoreSpi method setPrivateKeyEntry.

private void setPrivateKeyEntry(String alias, PrivateKey key, Certificate[] chain, java.security.KeyStore.ProtectionParameter param) throws KeyStoreException {
    int flags = 0;
    KeyProtection spec;
    if (param == null) {
        spec = getLegacyKeyProtectionParameter(key);
    } else if (param instanceof KeyStoreParameter) {
        spec = getLegacyKeyProtectionParameter(key);
        KeyStoreParameter legacySpec = (KeyStoreParameter) param;
        if (legacySpec.isEncryptionRequired()) {
            flags = KeyStore.FLAG_ENCRYPTED;
        }
    } else if (param instanceof KeyProtection) {
        spec = (KeyProtection) param;
    } else {
        throw new KeyStoreException("Unsupported protection parameter class:" + param.getClass().getName() + ". Supported: " + KeyProtection.class.getName() + ", " + KeyStoreParameter.class.getName());
    }
    // Make sure the chain exists since this is a PrivateKey
    if ((chain == null) || (chain.length == 0)) {
        throw new KeyStoreException("Must supply at least one Certificate with PrivateKey");
    }
    // Do chain type checking.
    X509Certificate[] x509chain = new X509Certificate[chain.length];
    for (int i = 0; i < chain.length; i++) {
        if (!"X.509".equals(chain[i].getType())) {
            throw new KeyStoreException("Certificates must be in X.509 format: invalid cert #" + i);
        }
        if (!(chain[i] instanceof X509Certificate)) {
            throw new KeyStoreException("Certificates must be in X.509 format: invalid cert #" + i);
        }
        x509chain[i] = (X509Certificate) chain[i];
    }
    final byte[] userCertBytes;
    try {
        userCertBytes = x509chain[0].getEncoded();
    } catch (CertificateEncodingException e) {
        throw new KeyStoreException("Failed to encode certificate #0", e);
    }
    /*
         * If we have a chain, store it in the CA certificate slot for this
         * alias as concatenated DER-encoded certificates. These can be
         * deserialized by {@link CertificateFactory#generateCertificates}.
         */
    final byte[] chainBytes;
    if (chain.length > 1) {
        /*
             * The chain is passed in as {user_cert, ca_cert_1, ca_cert_2, ...}
             * so we only need the certificates starting at index 1.
             */
        final byte[][] certsBytes = new byte[x509chain.length - 1][];
        int totalCertLength = 0;
        for (int i = 0; i < certsBytes.length; i++) {
            try {
                certsBytes[i] = x509chain[i + 1].getEncoded();
                totalCertLength += certsBytes[i].length;
            } catch (CertificateEncodingException e) {
                throw new KeyStoreException("Failed to encode certificate #" + i, e);
            }
        }
        /*
             * Serialize this into one byte array so we can later call
             * CertificateFactory#generateCertificates to recover them.
             */
        chainBytes = new byte[totalCertLength];
        int outputOffset = 0;
        for (int i = 0; i < certsBytes.length; i++) {
            final int certLength = certsBytes[i].length;
            System.arraycopy(certsBytes[i], 0, chainBytes, outputOffset, certLength);
            outputOffset += certLength;
            certsBytes[i] = null;
        }
    } else {
        chainBytes = null;
    }
    final String pkeyAlias;
    if (key instanceof AndroidKeyStorePrivateKey) {
        pkeyAlias = ((AndroidKeyStoreKey) key).getAlias();
    } else {
        pkeyAlias = null;
    }
    byte[] pkcs8EncodedPrivateKeyBytes;
    KeymasterArguments importArgs;
    final boolean shouldReplacePrivateKey;
    if (pkeyAlias != null && pkeyAlias.startsWith(Credentials.USER_PRIVATE_KEY)) {
        final String keySubalias = pkeyAlias.substring(Credentials.USER_PRIVATE_KEY.length());
        if (!alias.equals(keySubalias)) {
            throw new KeyStoreException("Can only replace keys with same alias: " + alias + " != " + keySubalias);
        }
        shouldReplacePrivateKey = false;
        importArgs = null;
        pkcs8EncodedPrivateKeyBytes = null;
    } else {
        shouldReplacePrivateKey = true;
        // Make sure the PrivateKey format is the one we support.
        final String keyFormat = key.getFormat();
        if ((keyFormat == null) || (!"PKCS#8".equals(keyFormat))) {
            throw new KeyStoreException("Unsupported private key export format: " + keyFormat + ". Only private keys which export their key material in PKCS#8 format are" + " supported.");
        }
        // Make sure we can actually encode the key.
        pkcs8EncodedPrivateKeyBytes = key.getEncoded();
        if (pkcs8EncodedPrivateKeyBytes == null) {
            throw new KeyStoreException("Private key did not export any key material");
        }
        importArgs = new KeymasterArguments();
        try {
            importArgs.addEnum(KeymasterDefs.KM_TAG_ALGORITHM, KeyProperties.KeyAlgorithm.toKeymasterAsymmetricKeyAlgorithm(key.getAlgorithm()));
            @KeyProperties.PurposeEnum int purposes = spec.getPurposes();
            importArgs.addEnums(KeymasterDefs.KM_TAG_PURPOSE, KeyProperties.Purpose.allToKeymaster(purposes));
            if (spec.isDigestsSpecified()) {
                importArgs.addEnums(KeymasterDefs.KM_TAG_DIGEST, KeyProperties.Digest.allToKeymaster(spec.getDigests()));
            }
            importArgs.addEnums(KeymasterDefs.KM_TAG_BLOCK_MODE, KeyProperties.BlockMode.allToKeymaster(spec.getBlockModes()));
            int[] keymasterEncryptionPaddings = KeyProperties.EncryptionPadding.allToKeymaster(spec.getEncryptionPaddings());
            if (((purposes & KeyProperties.PURPOSE_ENCRYPT) != 0) && (spec.isRandomizedEncryptionRequired())) {
                for (int keymasterPadding : keymasterEncryptionPaddings) {
                    if (!KeymasterUtils.isKeymasterPaddingSchemeIndCpaCompatibleWithAsymmetricCrypto(keymasterPadding)) {
                        throw new KeyStoreException("Randomized encryption (IND-CPA) required but is violated by" + " encryption padding mode: " + KeyProperties.EncryptionPadding.fromKeymaster(keymasterPadding) + ". See KeyProtection documentation.");
                    }
                }
            }
            importArgs.addEnums(KeymasterDefs.KM_TAG_PADDING, keymasterEncryptionPaddings);
            importArgs.addEnums(KeymasterDefs.KM_TAG_PADDING, KeyProperties.SignaturePadding.allToKeymaster(spec.getSignaturePaddings()));
            KeymasterUtils.addUserAuthArgs(importArgs, spec.isUserAuthenticationRequired(), spec.getUserAuthenticationValidityDurationSeconds(), spec.isUserAuthenticationValidWhileOnBody(), spec.isInvalidatedByBiometricEnrollment());
            importArgs.addDateIfNotNull(KeymasterDefs.KM_TAG_ACTIVE_DATETIME, spec.getKeyValidityStart());
            importArgs.addDateIfNotNull(KeymasterDefs.KM_TAG_ORIGINATION_EXPIRE_DATETIME, spec.getKeyValidityForOriginationEnd());
            importArgs.addDateIfNotNull(KeymasterDefs.KM_TAG_USAGE_EXPIRE_DATETIME, spec.getKeyValidityForConsumptionEnd());
        } catch (IllegalArgumentException | IllegalStateException e) {
            throw new KeyStoreException(e);
        }
    }
    boolean success = false;
    try {
        // Store the private key, if necessary
        if (shouldReplacePrivateKey) {
            // Delete the stored private key and any related entries before importing the
            // provided key
            Credentials.deleteAllTypesForAlias(mKeyStore, alias, mUid);
            KeyCharacteristics resultingKeyCharacteristics = new KeyCharacteristics();
            int errorCode = mKeyStore.importKey(Credentials.USER_PRIVATE_KEY + alias, importArgs, KeymasterDefs.KM_KEY_FORMAT_PKCS8, pkcs8EncodedPrivateKeyBytes, mUid, flags, resultingKeyCharacteristics);
            if (errorCode != KeyStore.NO_ERROR) {
                throw new KeyStoreException("Failed to store private key", KeyStore.getKeyStoreException(errorCode));
            }
        } else {
            // Keep the stored private key around -- delete all other entry types
            Credentials.deleteCertificateTypesForAlias(mKeyStore, alias, mUid);
            Credentials.deleteSecretKeyTypeForAlias(mKeyStore, alias, mUid);
        }
        // Store the leaf certificate
        int errorCode = mKeyStore.insert(Credentials.USER_CERTIFICATE + alias, userCertBytes, mUid, flags);
        if (errorCode != KeyStore.NO_ERROR) {
            throw new KeyStoreException("Failed to store certificate #0", KeyStore.getKeyStoreException(errorCode));
        }
        // Store the certificate chain
        errorCode = mKeyStore.insert(Credentials.CA_CERTIFICATE + alias, chainBytes, mUid, flags);
        if (errorCode != KeyStore.NO_ERROR) {
            throw new KeyStoreException("Failed to store certificate chain", KeyStore.getKeyStoreException(errorCode));
        }
        success = true;
    } finally {
        if (!success) {
            if (shouldReplacePrivateKey) {
                Credentials.deleteAllTypesForAlias(mKeyStore, alias, mUid);
            } else {
                Credentials.deleteCertificateTypesForAlias(mKeyStore, alias, mUid);
                Credentials.deleteSecretKeyTypeForAlias(mKeyStore, alias, mUid);
            }
        }
    }
}

Example 12 with KeyProtection

use of android.security.keystore.KeyProtection in project android_frameworks_base by AOSPA.

the class AndroidKeyStoreSpi method getLegacyKeyProtectionParameter.

private static KeyProtection getLegacyKeyProtectionParameter(PrivateKey key) throws KeyStoreException {
    String keyAlgorithm = key.getAlgorithm();
    KeyProtection.Builder specBuilder;
    if (KeyProperties.KEY_ALGORITHM_EC.equalsIgnoreCase(keyAlgorithm)) {
        specBuilder = new KeyProtection.Builder(KeyProperties.PURPOSE_SIGN | KeyProperties.PURPOSE_VERIFY);
        // Authorized to be used with any digest (including no digest).
        // MD5 was never offered for Android Keystore for ECDSA.
        specBuilder.setDigests(KeyProperties.DIGEST_NONE, KeyProperties.DIGEST_SHA1, KeyProperties.DIGEST_SHA224, KeyProperties.DIGEST_SHA256, KeyProperties.DIGEST_SHA384, KeyProperties.DIGEST_SHA512);
    } else if (KeyProperties.KEY_ALGORITHM_RSA.equalsIgnoreCase(keyAlgorithm)) {
        specBuilder = new KeyProtection.Builder(KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT | KeyProperties.PURPOSE_SIGN | KeyProperties.PURPOSE_VERIFY);
        // Authorized to be used with any digest (including no digest).
        specBuilder.setDigests(KeyProperties.DIGEST_NONE, KeyProperties.DIGEST_MD5, KeyProperties.DIGEST_SHA1, KeyProperties.DIGEST_SHA224, KeyProperties.DIGEST_SHA256, KeyProperties.DIGEST_SHA384, KeyProperties.DIGEST_SHA512);
        // Authorized to be used with any encryption and signature padding
        // schemes (including no padding).
        specBuilder.setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE, KeyProperties.ENCRYPTION_PADDING_RSA_PKCS1, KeyProperties.ENCRYPTION_PADDING_RSA_OAEP);
        specBuilder.setSignaturePaddings(KeyProperties.SIGNATURE_PADDING_RSA_PKCS1, KeyProperties.SIGNATURE_PADDING_RSA_PSS);
        // Disable randomized encryption requirement to support encryption
        // padding NONE above.
        specBuilder.setRandomizedEncryptionRequired(false);
    } else {
        throw new KeyStoreException("Unsupported key algorithm: " + keyAlgorithm);
    }
    specBuilder.setUserAuthenticationRequired(false);
    return specBuilder.build();
}

Example 13 with KeyProtection

use of android.security.keystore.KeyProtection in project android_frameworks_base by DirtyUnicorns.

the class AndroidKeyStoreSpi method setSecretKeyEntry.

private void setSecretKeyEntry(String entryAlias, SecretKey key, java.security.KeyStore.ProtectionParameter param) throws KeyStoreException {
    if ((param != null) && (!(param instanceof KeyProtection))) {
        throw new KeyStoreException("Unsupported protection parameter class: " + param.getClass().getName() + ". Supported: " + KeyProtection.class.getName());
    }
    KeyProtection params = (KeyProtection) param;
    if (key instanceof AndroidKeyStoreSecretKey) {
        // KeyStore-backed secret key. It cannot be duplicated into another entry and cannot
        // overwrite its own entry.
        String keyAliasInKeystore = ((AndroidKeyStoreSecretKey) key).getAlias();
        if (keyAliasInKeystore == null) {
            throw new KeyStoreException("KeyStore-backed secret key does not have an alias");
        }
        if (!keyAliasInKeystore.startsWith(Credentials.USER_SECRET_KEY)) {
            throw new KeyStoreException("KeyStore-backed secret key has invalid alias: " + keyAliasInKeystore);
        }
        String keyEntryAlias = keyAliasInKeystore.substring(Credentials.USER_SECRET_KEY.length());
        if (!entryAlias.equals(keyEntryAlias)) {
            throw new KeyStoreException("Can only replace KeyStore-backed keys with same" + " alias: " + entryAlias + " != " + keyEntryAlias);
        }
        // This is the entry where this key is already stored. No need to do anything.
        if (params != null) {
            throw new KeyStoreException("Modifying KeyStore-backed key using protection" + " parameters not supported");
        }
        return;
    }
    if (params == null) {
        throw new KeyStoreException("Protection parameters must be specified when importing a symmetric key");
    }
    // Not a KeyStore-backed secret key -- import its key material into keystore.
    String keyExportFormat = key.getFormat();
    if (keyExportFormat == null) {
        throw new KeyStoreException("Only secret keys that export their key material are supported");
    } else if (!"RAW".equals(keyExportFormat)) {
        throw new KeyStoreException("Unsupported secret key material export format: " + keyExportFormat);
    }
    byte[] keyMaterial = key.getEncoded();
    if (keyMaterial == null) {
        throw new KeyStoreException("Key did not export its key material despite supporting" + " RAW format export");
    }
    KeymasterArguments args = new KeymasterArguments();
    try {
        int keymasterAlgorithm = KeyProperties.KeyAlgorithm.toKeymasterSecretKeyAlgorithm(key.getAlgorithm());
        args.addEnum(KeymasterDefs.KM_TAG_ALGORITHM, keymasterAlgorithm);
        int[] keymasterDigests;
        if (keymasterAlgorithm == KeymasterDefs.KM_ALGORITHM_HMAC) {
            // JCA HMAC key algorithm implies a digest (e.g., HmacSHA256 key algorithm
            // implies SHA-256 digest). Because keymaster HMAC key is authorized only for one
            // digest, we don't let import parameters override the digest implied by the key.
            // If the parameters specify digests at all, they must specify only one digest, the
            // only implied by key algorithm.
            int keymasterImpliedDigest = KeyProperties.KeyAlgorithm.toKeymasterDigest(key.getAlgorithm());
            if (keymasterImpliedDigest == -1) {
                throw new ProviderException("HMAC key algorithm digest unknown for key algorithm " + key.getAlgorithm());
            }
            keymasterDigests = new int[] { keymasterImpliedDigest };
            if (params.isDigestsSpecified()) {
                // Digest(s) explicitly specified in params -- check that the list consists of
                // exactly one digest, the one implied by key algorithm.
                int[] keymasterDigestsFromParams = KeyProperties.Digest.allToKeymaster(params.getDigests());
                if ((keymasterDigestsFromParams.length != 1) || (keymasterDigestsFromParams[0] != keymasterImpliedDigest)) {
                    throw new KeyStoreException("Unsupported digests specification: " + Arrays.asList(params.getDigests()) + ". Only " + KeyProperties.Digest.fromKeymaster(keymasterImpliedDigest) + " supported for HMAC key algorithm " + key.getAlgorithm());
                }
            }
        } else {
            // Key algorithm does not imply a digest.
            if (params.isDigestsSpecified()) {
                keymasterDigests = KeyProperties.Digest.allToKeymaster(params.getDigests());
            } else {
                keymasterDigests = EmptyArray.INT;
            }
        }
        args.addEnums(KeymasterDefs.KM_TAG_DIGEST, keymasterDigests);
        @KeyProperties.PurposeEnum int purposes = params.getPurposes();
        int[] keymasterBlockModes = KeyProperties.BlockMode.allToKeymaster(params.getBlockModes());
        if (((purposes & KeyProperties.PURPOSE_ENCRYPT) != 0) && (params.isRandomizedEncryptionRequired())) {
            for (int keymasterBlockMode : keymasterBlockModes) {
                if (!KeymasterUtils.isKeymasterBlockModeIndCpaCompatibleWithSymmetricCrypto(keymasterBlockMode)) {
                    throw new KeyStoreException("Randomized encryption (IND-CPA) required but may be violated by" + " block mode: " + KeyProperties.BlockMode.fromKeymaster(keymasterBlockMode) + ". See KeyProtection documentation.");
                }
            }
        }
        args.addEnums(KeymasterDefs.KM_TAG_PURPOSE, KeyProperties.Purpose.allToKeymaster(purposes));
        args.addEnums(KeymasterDefs.KM_TAG_BLOCK_MODE, keymasterBlockModes);
        if (params.getSignaturePaddings().length > 0) {
            throw new KeyStoreException("Signature paddings not supported for symmetric keys");
        }
        int[] keymasterPaddings = KeyProperties.EncryptionPadding.allToKeymaster(params.getEncryptionPaddings());
        args.addEnums(KeymasterDefs.KM_TAG_PADDING, keymasterPaddings);
        KeymasterUtils.addUserAuthArgs(args, params.isUserAuthenticationRequired(), params.getUserAuthenticationValidityDurationSeconds(), params.isUserAuthenticationValidWhileOnBody(), params.isInvalidatedByBiometricEnrollment());
        KeymasterUtils.addMinMacLengthAuthorizationIfNecessary(args, keymasterAlgorithm, keymasterBlockModes, keymasterDigests);
        args.addDateIfNotNull(KeymasterDefs.KM_TAG_ACTIVE_DATETIME, params.getKeyValidityStart());
        args.addDateIfNotNull(KeymasterDefs.KM_TAG_ORIGINATION_EXPIRE_DATETIME, params.getKeyValidityForOriginationEnd());
        args.addDateIfNotNull(KeymasterDefs.KM_TAG_USAGE_EXPIRE_DATETIME, params.getKeyValidityForConsumptionEnd());
        if (((purposes & KeyProperties.PURPOSE_ENCRYPT) != 0) && (!params.isRandomizedEncryptionRequired())) {
            // Permit caller-provided IV when encrypting with this key
            args.addBoolean(KeymasterDefs.KM_TAG_CALLER_NONCE);
        }
    } catch (IllegalArgumentException | IllegalStateException e) {
        throw new KeyStoreException(e);
    }
    Credentials.deleteAllTypesForAlias(mKeyStore, entryAlias, mUid);
    String keyAliasInKeystore = Credentials.USER_SECRET_KEY + entryAlias;
    int errorCode = mKeyStore.importKey(keyAliasInKeystore, args, KeymasterDefs.KM_KEY_FORMAT_RAW, keyMaterial, mUid, // flags
    0, new KeyCharacteristics());
    if (errorCode != KeyStore.NO_ERROR) {
        throw new KeyStoreException("Failed to import secret key. Keystore error code: " + errorCode);
    }
}

Example 14 with KeyProtection

use of android.security.keystore.KeyProtection in project android_frameworks_base by ResurrectionRemix.

the class AndroidKeyStoreSpi method getLegacyKeyProtectionParameter.

private static KeyProtection getLegacyKeyProtectionParameter(PrivateKey key) throws KeyStoreException {
    String keyAlgorithm = key.getAlgorithm();
    KeyProtection.Builder specBuilder;
    if (KeyProperties.KEY_ALGORITHM_EC.equalsIgnoreCase(keyAlgorithm)) {
        specBuilder = new KeyProtection.Builder(KeyProperties.PURPOSE_SIGN | KeyProperties.PURPOSE_VERIFY);
        // Authorized to be used with any digest (including no digest).
        // MD5 was never offered for Android Keystore for ECDSA.
        specBuilder.setDigests(KeyProperties.DIGEST_NONE, KeyProperties.DIGEST_SHA1, KeyProperties.DIGEST_SHA224, KeyProperties.DIGEST_SHA256, KeyProperties.DIGEST_SHA384, KeyProperties.DIGEST_SHA512);
    } else if (KeyProperties.KEY_ALGORITHM_RSA.equalsIgnoreCase(keyAlgorithm)) {
        specBuilder = new KeyProtection.Builder(KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT | KeyProperties.PURPOSE_SIGN | KeyProperties.PURPOSE_VERIFY);
        // Authorized to be used with any digest (including no digest).
        specBuilder.setDigests(KeyProperties.DIGEST_NONE, KeyProperties.DIGEST_MD5, KeyProperties.DIGEST_SHA1, KeyProperties.DIGEST_SHA224, KeyProperties.DIGEST_SHA256, KeyProperties.DIGEST_SHA384, KeyProperties.DIGEST_SHA512);
        // Authorized to be used with any encryption and signature padding
        // schemes (including no padding).
        specBuilder.setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE, KeyProperties.ENCRYPTION_PADDING_RSA_PKCS1, KeyProperties.ENCRYPTION_PADDING_RSA_OAEP);
        specBuilder.setSignaturePaddings(KeyProperties.SIGNATURE_PADDING_RSA_PKCS1, KeyProperties.SIGNATURE_PADDING_RSA_PSS);
        // Disable randomized encryption requirement to support encryption
        // padding NONE above.
        specBuilder.setRandomizedEncryptionRequired(false);
    } else {
        throw new KeyStoreException("Unsupported key algorithm: " + keyAlgorithm);
    }
    specBuilder.setUserAuthenticationRequired(false);
    return specBuilder.build();
}

Example 15 with KeyProtection

use of android.security.keystore.KeyProtection in project android_frameworks_base by crdroidandroid.

the class AndroidKeyStoreSpi method setPrivateKeyEntry.

private void setPrivateKeyEntry(String alias, PrivateKey key, Certificate[] chain, java.security.KeyStore.ProtectionParameter param) throws KeyStoreException {
    int flags = 0;
    KeyProtection spec;
    if (param == null) {
        spec = getLegacyKeyProtectionParameter(key);
    } else if (param instanceof KeyStoreParameter) {
        spec = getLegacyKeyProtectionParameter(key);
        KeyStoreParameter legacySpec = (KeyStoreParameter) param;
        if (legacySpec.isEncryptionRequired()) {
            flags = KeyStore.FLAG_ENCRYPTED;
        }
    } else if (param instanceof KeyProtection) {
        spec = (KeyProtection) param;
    } else {
        throw new KeyStoreException("Unsupported protection parameter class:" + param.getClass().getName() + ". Supported: " + KeyProtection.class.getName() + ", " + KeyStoreParameter.class.getName());
    }
    // Make sure the chain exists since this is a PrivateKey
    if ((chain == null) || (chain.length == 0)) {
        throw new KeyStoreException("Must supply at least one Certificate with PrivateKey");
    }
    // Do chain type checking.
    X509Certificate[] x509chain = new X509Certificate[chain.length];
    for (int i = 0; i < chain.length; i++) {
        if (!"X.509".equals(chain[i].getType())) {
            throw new KeyStoreException("Certificates must be in X.509 format: invalid cert #" + i);
        }
        if (!(chain[i] instanceof X509Certificate)) {
            throw new KeyStoreException("Certificates must be in X.509 format: invalid cert #" + i);
        }
        x509chain[i] = (X509Certificate) chain[i];
    }
    final byte[] userCertBytes;
    try {
        userCertBytes = x509chain[0].getEncoded();
    } catch (CertificateEncodingException e) {
        throw new KeyStoreException("Failed to encode certificate #0", e);
    }
    /*
         * If we have a chain, store it in the CA certificate slot for this
         * alias as concatenated DER-encoded certificates. These can be
         * deserialized by {@link CertificateFactory#generateCertificates}.
         */
    final byte[] chainBytes;
    if (chain.length > 1) {
        /*
             * The chain is passed in as {user_cert, ca_cert_1, ca_cert_2, ...}
             * so we only need the certificates starting at index 1.
             */
        final byte[][] certsBytes = new byte[x509chain.length - 1][];
        int totalCertLength = 0;
        for (int i = 0; i < certsBytes.length; i++) {
            try {
                certsBytes[i] = x509chain[i + 1].getEncoded();
                totalCertLength += certsBytes[i].length;
            } catch (CertificateEncodingException e) {
                throw new KeyStoreException("Failed to encode certificate #" + i, e);
            }
        }
        /*
             * Serialize this into one byte array so we can later call
             * CertificateFactory#generateCertificates to recover them.
             */
        chainBytes = new byte[totalCertLength];
        int outputOffset = 0;
        for (int i = 0; i < certsBytes.length; i++) {
            final int certLength = certsBytes[i].length;
            System.arraycopy(certsBytes[i], 0, chainBytes, outputOffset, certLength);
            outputOffset += certLength;
            certsBytes[i] = null;
        }
    } else {
        chainBytes = null;
    }
    final String pkeyAlias;
    if (key instanceof AndroidKeyStorePrivateKey) {
        pkeyAlias = ((AndroidKeyStoreKey) key).getAlias();
    } else {
        pkeyAlias = null;
    }
    byte[] pkcs8EncodedPrivateKeyBytes;
    KeymasterArguments importArgs;
    final boolean shouldReplacePrivateKey;
    if (pkeyAlias != null && pkeyAlias.startsWith(Credentials.USER_PRIVATE_KEY)) {
        final String keySubalias = pkeyAlias.substring(Credentials.USER_PRIVATE_KEY.length());
        if (!alias.equals(keySubalias)) {
            throw new KeyStoreException("Can only replace keys with same alias: " + alias + " != " + keySubalias);
        }
        shouldReplacePrivateKey = false;
        importArgs = null;
        pkcs8EncodedPrivateKeyBytes = null;
    } else {
        shouldReplacePrivateKey = true;
        // Make sure the PrivateKey format is the one we support.
        final String keyFormat = key.getFormat();
        if ((keyFormat == null) || (!"PKCS#8".equals(keyFormat))) {
            throw new KeyStoreException("Unsupported private key export format: " + keyFormat + ". Only private keys which export their key material in PKCS#8 format are" + " supported.");
        }
        // Make sure we can actually encode the key.
        pkcs8EncodedPrivateKeyBytes = key.getEncoded();
        if (pkcs8EncodedPrivateKeyBytes == null) {
            throw new KeyStoreException("Private key did not export any key material");
        }
        importArgs = new KeymasterArguments();
        try {
            importArgs.addEnum(KeymasterDefs.KM_TAG_ALGORITHM, KeyProperties.KeyAlgorithm.toKeymasterAsymmetricKeyAlgorithm(key.getAlgorithm()));
            @KeyProperties.PurposeEnum int purposes = spec.getPurposes();
            importArgs.addEnums(KeymasterDefs.KM_TAG_PURPOSE, KeyProperties.Purpose.allToKeymaster(purposes));
            if (spec.isDigestsSpecified()) {
                importArgs.addEnums(KeymasterDefs.KM_TAG_DIGEST, KeyProperties.Digest.allToKeymaster(spec.getDigests()));
            }
            importArgs.addEnums(KeymasterDefs.KM_TAG_BLOCK_MODE, KeyProperties.BlockMode.allToKeymaster(spec.getBlockModes()));
            int[] keymasterEncryptionPaddings = KeyProperties.EncryptionPadding.allToKeymaster(spec.getEncryptionPaddings());
            if (((purposes & KeyProperties.PURPOSE_ENCRYPT) != 0) && (spec.isRandomizedEncryptionRequired())) {
                for (int keymasterPadding : keymasterEncryptionPaddings) {
                    if (!KeymasterUtils.isKeymasterPaddingSchemeIndCpaCompatibleWithAsymmetricCrypto(keymasterPadding)) {
                        throw new KeyStoreException("Randomized encryption (IND-CPA) required but is violated by" + " encryption padding mode: " + KeyProperties.EncryptionPadding.fromKeymaster(keymasterPadding) + ". See KeyProtection documentation.");
                    }
                }
            }
            importArgs.addEnums(KeymasterDefs.KM_TAG_PADDING, keymasterEncryptionPaddings);
            importArgs.addEnums(KeymasterDefs.KM_TAG_PADDING, KeyProperties.SignaturePadding.allToKeymaster(spec.getSignaturePaddings()));
            KeymasterUtils.addUserAuthArgs(importArgs, spec.isUserAuthenticationRequired(), spec.getUserAuthenticationValidityDurationSeconds(), spec.isUserAuthenticationValidWhileOnBody(), spec.isInvalidatedByBiometricEnrollment());
            importArgs.addDateIfNotNull(KeymasterDefs.KM_TAG_ACTIVE_DATETIME, spec.getKeyValidityStart());
            importArgs.addDateIfNotNull(KeymasterDefs.KM_TAG_ORIGINATION_EXPIRE_DATETIME, spec.getKeyValidityForOriginationEnd());
            importArgs.addDateIfNotNull(KeymasterDefs.KM_TAG_USAGE_EXPIRE_DATETIME, spec.getKeyValidityForConsumptionEnd());
        } catch (IllegalArgumentException | IllegalStateException e) {
            throw new KeyStoreException(e);
        }
    }
    boolean success = false;
    try {
        // Store the private key, if necessary
        if (shouldReplacePrivateKey) {
            // Delete the stored private key and any related entries before importing the
            // provided key
            Credentials.deleteAllTypesForAlias(mKeyStore, alias, mUid);
            KeyCharacteristics resultingKeyCharacteristics = new KeyCharacteristics();
            int errorCode = mKeyStore.importKey(Credentials.USER_PRIVATE_KEY + alias, importArgs, KeymasterDefs.KM_KEY_FORMAT_PKCS8, pkcs8EncodedPrivateKeyBytes, mUid, flags, resultingKeyCharacteristics);
            if (errorCode != KeyStore.NO_ERROR) {
                throw new KeyStoreException("Failed to store private key", KeyStore.getKeyStoreException(errorCode));
            }
        } else {
            // Keep the stored private key around -- delete all other entry types
            Credentials.deleteCertificateTypesForAlias(mKeyStore, alias, mUid);
            Credentials.deleteSecretKeyTypeForAlias(mKeyStore, alias, mUid);
        }
        // Store the leaf certificate
        int errorCode = mKeyStore.insert(Credentials.USER_CERTIFICATE + alias, userCertBytes, mUid, flags);
        if (errorCode != KeyStore.NO_ERROR) {
            throw new KeyStoreException("Failed to store certificate #0", KeyStore.getKeyStoreException(errorCode));
        }
        // Store the certificate chain
        errorCode = mKeyStore.insert(Credentials.CA_CERTIFICATE + alias, chainBytes, mUid, flags);
        if (errorCode != KeyStore.NO_ERROR) {
            throw new KeyStoreException("Failed to store certificate chain", KeyStore.getKeyStoreException(errorCode));
        }
        success = true;
    } finally {
        if (!success) {
            if (shouldReplacePrivateKey) {
                Credentials.deleteAllTypesForAlias(mKeyStore, alias, mUid);
            } else {
                Credentials.deleteCertificateTypesForAlias(mKeyStore, alias, mUid);
                Credentials.deleteSecretKeyTypeForAlias(mKeyStore, alias, mUid);
            }
        }
    }
}