# Use AWS Private CA to implement mDL certificates
mDL examplesAWS Private CA API support for mDL

Added API support for creating certificates that conform to the [ISO/IEC standard for mobile driving license (mDL)](https://www.iso.org/standard/69084.html).

You can use the AWS Private Certificate Authority API to create certificates that conform to the [ISO/IEC standard for mobile driving license (mDL) ](https://www.iso.org/standard/69084.html). This standard establishes interface specifications for the implementation of a driving license in association with a mobile device, including certificate configurations.

**Topics**
+ [

# Activate an issuing authority certificate authority (IACA) certificate
](JavaApiMDL-ActivateIACA.md)
+ [

# Create a document signer certificate
](JavaApiMDL-IssueDS.md)

# Activate an issuing authority certificate authority (IACA) certificate


This Java sample shows how to use the [BlankRootCACertificate\$1PathLen0\$1APIPassthrough/V1 definition](template-definitions.md#BlankRootCACertificate_PathLen0_APIPassthrough) template to create and install an [ISO/IEC mDL standard](https://www.iso.org/standard/69084.html)-compliant issuing authority certificate authority (IACA) certificate. You must generate base64-encoded values for `KeyUsage`, `IssuerAlternativeName`, and `CRLDistributionPoint`, and pass them through `CustomExtensions`.

**Note**  
The IACA link certificate establishes a trust path from the old IACA root certificate to the new IACA root certificate. The issuing authority can generate and distribute an IACA link certificate during the IACA re-key process. You cannot issue an IACA link certificate by using an IACA root certificate with `pathLen=0` set.

The example calls the following AWS Private CA API actions:
+ [CreateCertificateAuthority](https://docs.aws.amazon.com/privateca/latest/APIReference/API_CreateCertificateAuthority.html)
+ [GetCertificateAuthorityCsr](https://docs.aws.amazon.com/privateca/latest/APIReference/API_GetCertificateAuthorityCsr.html)
+ [IssueCertificate](https://docs.aws.amazon.com/privateca/latest/APIReference/API_IssueCertificate.html)
+ [GetCertificate](https://docs.aws.amazon.com/privateca/latest/APIReference/API_GetCertificate.html)
+ [ImportCertificateAuthorityCertificate](https://docs.aws.amazon.com/privateca/latest/APIReference/API_ImportCertificateAuthorityCertificate.html)

```
package com.amazonaws.samples.mdl;

import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.auth.AWSStaticCredentialsProvider;

import com.amazonaws.services.acmpca.AWSACMPCA;
import com.amazonaws.services.acmpca.AWSACMPCAClientBuilder;

import com.amazonaws.services.acmpca.model.ASN1Subject;
import com.amazonaws.services.acmpca.model.ApiPassthrough;
import com.amazonaws.services.acmpca.model.CertificateAuthorityConfiguration;
import com.amazonaws.services.acmpca.model.CertificateAuthorityType;
import com.amazonaws.services.acmpca.model.CreateCertificateAuthorityResult;
import com.amazonaws.services.acmpca.model.CreateCertificateAuthorityRequest;
import com.amazonaws.services.acmpca.model.CustomExtension;
import com.amazonaws.services.acmpca.model.Extensions;
import com.amazonaws.services.acmpca.model.KeyAlgorithm;
import com.amazonaws.services.acmpca.model.SigningAlgorithm;

import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Base64;
import java.util.Objects;

import com.amazonaws.services.acmpca.model.GetCertificateAuthorityCsrRequest;
import com.amazonaws.services.acmpca.model.GetCertificateAuthorityCsrResult;
import com.amazonaws.services.acmpca.model.GetCertificateRequest;
import com.amazonaws.services.acmpca.model.GetCertificateResult;
import com.amazonaws.services.acmpca.model.ImportCertificateAuthorityCertificateRequest;
import com.amazonaws.services.acmpca.model.IssueCertificateRequest;
import com.amazonaws.services.acmpca.model.IssueCertificateResult;
import com.amazonaws.services.acmpca.model.Validity;

import com.amazonaws.AmazonClientException;
import com.amazonaws.services.acmpca.model.CertificateMismatchException;
import com.amazonaws.services.acmpca.model.ConcurrentModificationException;
import com.amazonaws.services.acmpca.model.LimitExceededException;
import com.amazonaws.services.acmpca.model.InvalidArgsException;
import com.amazonaws.services.acmpca.model.InvalidArnException;
import com.amazonaws.services.acmpca.model.InvalidPolicyException;
import com.amazonaws.services.acmpca.model.InvalidStateException;
import com.amazonaws.services.acmpca.model.MalformedCertificateException;
import com.amazonaws.services.acmpca.model.MalformedCSRException;
import com.amazonaws.services.acmpca.model.RequestFailedException;
import com.amazonaws.services.acmpca.model.RequestInProgressException;
import com.amazonaws.services.acmpca.model.ResourceNotFoundException;
import com.amazonaws.services.acmpca.model.AWSACMPCAException;

import com.amazonaws.waiters.Waiter;
import com.amazonaws.waiters.WaiterParameters;
import com.amazonaws.waiters.WaiterTimedOutException;
import com.amazonaws.waiters.WaiterUnrecoverableException;

import org.bouncycastle.asn1.x509.GeneralNames;
import org.bouncycastle.asn1.x509.GeneralName;
import org.bouncycastle.asn1.x509.CRLDistPoint;
import org.bouncycastle.asn1.x509.DistributionPoint;
import org.bouncycastle.asn1.x509.DistributionPointName;
import org.bouncycastle.asn1.x509.KeyUsage;
import org.bouncycastle.jce.X509KeyUsage;

import lombok.SneakyThrows;

public class IssuingAuthorityCertificateAuthorityActivation {
    public static void main(String[] args) throws Exception {
        // Define the endpoint region for your sample.
        String endpointRegion = null;  // Substitute your region here, e.g. "ap-southeast-2"
        if (endpointRegion == null) throw new Exception("Region cannot be null");

        // Define a CA subject.
        ASN1Subject subject = new ASN1Subject()
                .withCountry("US") // mDL spec requires ISO 3166-1-alpha-2 country code e.g. "US"
                .withCommonName("mDL Test IACA");

        // Define the CA configuration.
        CertificateAuthorityConfiguration configCA = new CertificateAuthorityConfiguration()
                .withKeyAlgorithm(KeyAlgorithm.EC_prime256v1)
                .withSigningAlgorithm(SigningAlgorithm.SHA256WITHECDSA)
                .withSubject(subject);

        // Define a certificate authority type
        CertificateAuthorityType CAType = CertificateAuthorityType.ROOT;

        // Execute core code samples for Root CA activation in sequence
        AWSACMPCA client = buildClient(endpointRegion);
        String rootCAArn = createCertificateAuthority(configCA, CAType, client);
        String csr = getCertificateAuthorityCsr(rootCAArn, client);
        String rootCertificateArn = issueCertificate(rootCAArn, csr, client);
        String rootCertificate = getCertificate(rootCertificateArn, rootCAArn, client);
        importCertificateAuthorityCertificate(rootCertificate, rootCAArn, client);
    }

    private static AWSACMPCA buildClient(String endpointRegion) {
        // Get your credentials from the C:\Users\name\.aws\credentials file
        // in Windows or the .aws/credentials file in Linux.
        AWSCredentials credentials = null;
        try {
            credentials = new ProfileCredentialsProvider("default").getCredentials();
        } catch (Exception e) {
            throw new AmazonClientException("Cannot load your credentials from disk", e);
        }

        // Create a client that you can use to make requests.
        AWSACMPCA client = AWSACMPCAClientBuilder.standard()
                .withRegion(endpointRegion)
                .withCredentials(new AWSStaticCredentialsProvider(credentials))
                .build();

        return client;
    }

    private static String createCertificateAuthority(CertificateAuthorityConfiguration configCA, CertificateAuthorityType CAtype, AWSACMPCA client) {
        // Create the request object.
        CreateCertificateAuthorityRequest createCARequest = new CreateCertificateAuthorityRequest()
                .withCertificateAuthorityConfiguration(configCA)
                .withIdempotencyToken("123987")
                .withCertificateAuthorityType(CAtype);

        // Create the private CA.
        CreateCertificateAuthorityResult createCAResult = null;
        try {
            createCAResult = client.createCertificateAuthority(createCARequest);
        } catch (InvalidArgsException ex) {
            throw ex;
        } catch (InvalidPolicyException ex) {
            throw ex;
        } catch (LimitExceededException ex) {
            throw ex;
        }

        // Get the ARN of the private CA.
        String rootCAArn = createCAResult.getCertificateAuthorityArn();
        System.out.println("Issuing Authority Certificate Authority (IACA) Arn: " + rootCAArn);

        return rootCAArn;
    }

    private static String getCertificateAuthorityCsr(String rootCAArn, AWSACMPCA client) {

        // Create the CSR request object and set the CA ARN.
        GetCertificateAuthorityCsrRequest csrRequest = new GetCertificateAuthorityCsrRequest()
                .withCertificateAuthorityArn(rootCAArn);

        // Create waiter to wait on successful creation of the CSR file.
        Waiter<GetCertificateAuthorityCsrRequest> getCSRWaiter = client.waiters().certificateAuthorityCSRCreated();
        try {
            getCSRWaiter.run(new WaiterParameters<>(csrRequest));
        } catch (WaiterUnrecoverableException e) {
            // Explicit short circuit when the recourse transitions into
            // an undesired state.
        } catch (WaiterTimedOutException e) {
            // Failed to transition into desired state even after polling.
        } catch (AWSACMPCAException e) {
            // Unexpected service exception.
        }

        // Get the CSR.
        GetCertificateAuthorityCsrResult csrResult = null;
        try {
            csrResult = client.getCertificateAuthorityCsr(csrRequest);
        } catch (RequestInProgressException ex) {
            throw ex;
        } catch (ResourceNotFoundException ex) {
            throw ex;
        } catch (InvalidArnException ex) {
            throw ex;
        } catch (RequestFailedException ex) {
            throw ex;
        }

        // Get and display the CSR;
        String csr = csrResult.getCsr();
        System.out.println("CSR:");
        System.out.println(csr);

        return csr;
    }

    @SneakyThrows
    private static String issueCertificate(String rootCAArn, String csr, AWSACMPCA client) {
        IssueCertificateRequest issueRequest = new IssueCertificateRequest()
                .withCertificateAuthorityArn(rootCAArn)
                .withTemplateArn("arn:aws:acm-pca:::template/BlankRootCACertificate_PathLen0_APIPassthrough/V1")
                .withSigningAlgorithm(SigningAlgorithm.SHA256WITHECDSA)
                .withIdempotencyToken("1234");

        // Set the CSR.
        ByteBuffer csrByteBuffer = stringToByteBuffer(csr);
        issueRequest.setCsr(csrByteBuffer);

        // Set the validity period for the certificate to be issued.
        Validity validity = new Validity()
                .withValue(3650L)
                .withType("DAYS");
        issueRequest.setValidity(validity);

        // Generate base64 encoded extension value for KeyUsage
        KeyUsage keyUsage = new KeyUsage(X509KeyUsage.keyCertSign + X509KeyUsage.cRLSign);
        byte[] kuBytes = keyUsage.getEncoded();
        String base64EncodedKUValue = Base64.getEncoder().encodeToString(kuBytes);

        CustomExtension keyUsageCustomExtension = new CustomExtension()
                .withObjectIdentifier("2.5.29.15") // KeyUsage Extension OID
                .withValue(base64EncodedKUValue)
                .withCritical(true);

        // Generate base64 encoded extension value for IssuerAlternativeName
        GeneralNames issuerAlternativeName = new GeneralNames(new GeneralName(GeneralName.uniformResourceIdentifier, "https://issuer-alternative-name.com"));
        String base64EncodedIANValue = Base64.getEncoder().encodeToString(issuerAlternativeName.getEncoded());

        CustomExtension ianCustomExtension = new CustomExtension()
                .withValue(base64EncodedIANValue)
                .withObjectIdentifier("2.5.29.18"); // IssuerAlternativeName Extension OID

        // Generate base64 encoded extension value for CRLDistributionPoint
        CRLDistPoint crlDistPoint = new CRLDistPoint(new DistributionPoint[]{new DistributionPoint(new DistributionPointName(
                new GeneralNames(new GeneralName(GeneralName.uniformResourceIdentifier, "dummycrl.crl"))), null, null)});
        String base64EncodedCDPValue = Base64.getEncoder().encodeToString(crlDistPoint.getEncoded());

        CustomExtension cdpCustomExtension = new CustomExtension()
                .withValue(base64EncodedCDPValue)
                .withObjectIdentifier("2.5.29.31"); // CRLDistributionPoint Extension OID

        // Add custom extension to api-passthrough
        Extensions extensions = new Extensions()
                .withCustomExtensions(Arrays.asList(keyUsageCustomExtension, ianCustomExtension, cdpCustomExtension));
        ApiPassthrough apiPassthrough = new ApiPassthrough()
                .withExtensions(extensions);
        issueRequest.setApiPassthrough(apiPassthrough);

        // Issue the certificate.
        IssueCertificateResult issueResult = null;
        try {
            issueResult = client.issueCertificate(issueRequest);
        } catch (LimitExceededException ex) {
            throw ex;
        } catch (ResourceNotFoundException ex) {
            throw ex;
        } catch (InvalidStateException ex) {
            throw ex;
        } catch (InvalidArnException ex) {
            throw ex;
        } catch (InvalidArgsException ex) {
            throw ex;
        } catch (MalformedCSRException ex) {
            throw ex;
        }

        // Get and display the certificate ARN.
        String rootCertificateArn = issueResult.getCertificateArn();
        System.out.println("mDL IACA Certificate Arn: " + rootCertificateArn);

        return rootCertificateArn;
    }

    private static String getCertificate(String rootCertificateArn, String rootCAArn, AWSACMPCA client) {

        // Create a request object.
        GetCertificateRequest certificateRequest = new GetCertificateRequest()
                .withCertificateArn(rootCertificateArn)
                .withCertificateAuthorityArn(rootCAArn);

        // Create waiter to wait on successful creation of the certificate file.
        Waiter<GetCertificateRequest> getCertificateWaiter = client.waiters().certificateIssued();
        try {
            getCertificateWaiter.run(new WaiterParameters<>(certificateRequest));
        } catch (WaiterUnrecoverableException e) {
            // Explicit short circuit when the recourse transitions into
            // an undesired state.
        } catch (WaiterTimedOutException e) {
            // Failed to transition into desired state even after polling.
        } catch (AWSACMPCAException e) {
            // Unexpected service exception.
        }

        // Get the certificate and certificate chain.
        GetCertificateResult certificateResult = null;
        try {
            certificateResult = client.getCertificate(certificateRequest);
        } catch (RequestInProgressException ex) {
            throw ex;
        } catch (RequestFailedException ex) {
            throw ex;
        } catch (ResourceNotFoundException ex) {
            throw ex;
        } catch (InvalidArnException ex) {
            throw ex;
        } catch (InvalidStateException ex) {
            throw ex;
        }

        // Get the certificate and certificate chain and display the result.
        String rootCertificate = certificateResult.getCertificate();
        System.out.println(rootCertificate);

        return rootCertificate;
    }

    private static void importCertificateAuthorityCertificate(String rootCertificate, String rootCAArn, AWSACMPCA client) {

        // Create the request object and set the signed certificate, chain and CA ARN.
        ImportCertificateAuthorityCertificateRequest importRequest =
                new ImportCertificateAuthorityCertificateRequest()
                        .withCertificateChain(null)
                        .withCertificateAuthorityArn(rootCAArn);

        ByteBuffer certByteBuffer = stringToByteBuffer(rootCertificate);
        importRequest.setCertificate(certByteBuffer);

        // Import the certificate.
        try {
            client.importCertificateAuthorityCertificate(importRequest);
        } catch (CertificateMismatchException ex) {
            throw ex;
        } catch (MalformedCertificateException ex) {
            throw ex;
        } catch (InvalidArnException ex) {
            throw ex;
        } catch (ResourceNotFoundException ex) {
            throw ex;
        } catch (RequestInProgressException ex) {
            throw ex;
        } catch (ConcurrentModificationException ex) {
            throw ex;
        } catch (RequestFailedException ex) {
            throw ex;
        }

        System.out.println("Root CA certificate successfully imported.");
        System.out.println("Root CA activated successfully.");
    }

    private static ByteBuffer stringToByteBuffer(final String string) {
        if (Objects.isNull(string)) {
            return null;
        }
        byte[] bytes = string.getBytes(StandardCharsets.UTF_8);
        return ByteBuffer.wrap(bytes);
    }
}
```

# Create a document signer certificate


This Java sample shows how to use the [BlankEndEntityCertificate\$1APIPassthrough/V1](template-definitions.md#BlankEndEntityCertificate_APIPassthrough) template to create a [ISO/IEC mDL standard](https://www.iso.org/standard/69084.html)-compliant document signer certificate. You must generate base64-encoded values for `KeyUsage`, `IssuerAlternativeName`, and `CRLDistributionPoint` and pass them through `CustomExtensions`.

The example calls the following AWS Private CA API action:
+ [IssueCertificate](https://docs.aws.amazon.com/privateca/latest/APIReference/API_IssueCertificate.html)

```
package com.amazonaws.samples.mdl;

import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.auth.AWSStaticCredentialsProvider;

import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Base64;
import java.util.Objects;

import com.amazonaws.services.acmpca.AWSACMPCA;
import com.amazonaws.services.acmpca.AWSACMPCAClientBuilder;

import com.amazonaws.services.acmpca.model.ASN1Subject;
import com.amazonaws.services.acmpca.model.ApiPassthrough;
import com.amazonaws.services.acmpca.model.ExtendedKeyUsage;
import com.amazonaws.services.acmpca.model.CustomExtension;
import com.amazonaws.services.acmpca.model.Extensions;
import com.amazonaws.services.acmpca.model.IssueCertificateRequest;
import com.amazonaws.services.acmpca.model.IssueCertificateResult;
import com.amazonaws.services.acmpca.model.SigningAlgorithm;
import com.amazonaws.services.acmpca.model.Validity;

import com.amazonaws.AmazonClientException;
import com.amazonaws.services.acmpca.model.LimitExceededException;
import com.amazonaws.services.acmpca.model.ResourceNotFoundException;
import com.amazonaws.services.acmpca.model.InvalidStateException;
import com.amazonaws.services.acmpca.model.InvalidArnException;
import com.amazonaws.services.acmpca.model.InvalidArgsException;
import com.amazonaws.services.acmpca.model.MalformedCSRException;

import org.bouncycastle.asn1.x509.GeneralNames;
import org.bouncycastle.asn1.x509.GeneralName;
import org.bouncycastle.asn1.x509.CRLDistPoint;
import org.bouncycastle.asn1.x509.DistributionPoint;
import org.bouncycastle.asn1.x509.DistributionPointName;
import org.bouncycastle.asn1.x509.KeyUsage;
import org.bouncycastle.jce.X509KeyUsage;

public class IssueDocumentSignerCertificate {
    public static ByteBuffer stringToByteBuffer(final String string) {
        if (Objects.isNull(string)) {
            return null;
        }
        byte[] bytes = string.getBytes(StandardCharsets.UTF_8);
        return ByteBuffer.wrap(bytes);
    }

    public static void main(String[] args) throws Exception {

        // Get your credentials from the C:\Users\name\.aws\credentials file
        // in Windows or the .aws/credentials file in Linux.
        AWSCredentials credentials = null;
        try {
            credentials = new ProfileCredentialsProvider("default").getCredentials();
        } catch (Exception e) {
            throw new AmazonClientException("Cannot load your credentials from disk", e);
        }

        // Create a client that you can use to make requests.
        String endpointRegion = null;  // Substitute your region here, e.g. "ap-southeast-2"
        if (endpointRegion == null) throw new Exception("Region cannot be null");

        AWSACMPCA client = AWSACMPCAClientBuilder.standard()
                .withRegion(endpointRegion)
                .withCredentials(new AWSStaticCredentialsProvider(credentials))
                .build();

        // Create a certificate request:
        String caArn = null;
        if (caArn == null) throw new Exception("Certificate authority ARN cannot be null");

        IssueCertificateRequest req = new IssueCertificateRequest()
                .withCertificateAuthorityArn(caArn)
                .withTemplateArn("arn:aws:acm-pca:::template/BlankEndEntityCertificate_APIPassthrough/V1")
                .withSigningAlgorithm(SigningAlgorithm.SHA256WITHECDSA)
                .withIdempotencyToken("1234");

        // Specify the certificate signing request (CSR) for the certificate to be signed and issued.
        // Format: "-----BEGIN CERTIFICATE REQUEST-----\n" +
        //         "base64-encoded certificate\n" +
        //         "-----END CERTIFICATE REQUEST-----\n";
        String strCSR = null;
        if (strCSR == null) throw new Exception("CSR string cannot be null");

        ByteBuffer csrByteBuffer = stringToByteBuffer(strCSR);
        req.setCsr(csrByteBuffer);

        // Set the validity period for the certificate to be issued.
        Validity validity = new Validity()
                .withValue(365L)
                .withType("DAYS");
        req.setValidity(validity);

        // Define a cert subject.
        ASN1Subject subject = new ASN1Subject()
                .withCountry("US") // mDL spec requires ISO 3166-1-alpha-2 country code e.g. "US"
                .withCommonName("mDL Test DS");

        ApiPassthrough apiPassthrough = new ApiPassthrough()
                .withSubject(subject);

        // Generate base64 encoded extension value for KeyUsage
        KeyUsage keyUsage = new KeyUsage(X509KeyUsage.digitalSignature);
        byte[] kuBytes = keyUsage.getEncoded();
        String base64EncodedKUValue = Base64.getEncoder().encodeToString(kuBytes);

        CustomExtension customKeyUsageExtension = new CustomExtension()
                .withObjectIdentifier("2.5.29.15") // KeyUsage Extension OID
                .withValue(base64EncodedKUValue)
                .withCritical(true);

        // Generate base64 encoded extension value for IssuerAlternativeName
        GeneralNames issuerAlternativeName = new GeneralNames(new GeneralName(GeneralName.uniformResourceIdentifier, "https://issuer-alternative-name.com"));
        String base64EncodedIANValue = Base64.getEncoder().encodeToString(issuerAlternativeName.getEncoded());

        CustomExtension ianCustomExtension = new CustomExtension()
                .withValue(base64EncodedIANValue)
                .withObjectIdentifier("2.5.29.18"); // IssuerAlternativeName Extension OID

        // Generate base64 encoded extension value for CRLDistributionPoint
        CRLDistPoint crlDistPoint = new CRLDistPoint(new DistributionPoint[]{new DistributionPoint(new DistributionPointName(
                new GeneralNames(new GeneralName(GeneralName.uniformResourceIdentifier, "dummycrl.crl"))), null, null)});
        String base64EncodedCDPValue = Base64.getEncoder().encodeToString(crlDistPoint.getEncoded());

        CustomExtension cdpCustomExtension = new CustomExtension()
                .withValue(base64EncodedCDPValue)
                .withObjectIdentifier("2.5.29.31"); // CRLDistributionPoint Extension OID

        // Generate EKU
        ExtendedKeyUsage eku = new ExtendedKeyUsage()
                .withExtendedKeyUsageObjectIdentifier("1.0.18013.5.1.2"); // EKU value reserved for mDL DS

        // Set KeyUsage, ExtendedKeyUsage, IssuerAlternativeName, CRL Distribution Point extensions to api-passthrough
        Extensions extensions = new Extensions()
                .withCustomExtensions(Arrays.asList(customKeyUsageExtension, ianCustomExtension, cdpCustomExtension))
                .withExtendedKeyUsage(Arrays.asList(eku));
        apiPassthrough.setExtensions(extensions);
        req.setApiPassthrough(apiPassthrough);

        // Issue the certificate.
        IssueCertificateResult result = null;
        try {
            result = client.issueCertificate(req);
        } catch (LimitExceededException ex) {
            throw ex;
        } catch (ResourceNotFoundException ex) {
            throw ex;
        } catch (InvalidStateException ex) {
            throw ex;
        } catch (InvalidArnException ex) {
            throw ex;
        } catch (InvalidArgsException ex) {
            throw ex;
        } catch (MalformedCSRException ex) {
            throw ex;
        }

        // Get and display the certificate ARN.
        String arn = result.getCertificateArn();
        System.out.println("mDL DS Certificate Arn: " + arn);
    }
}
```