(Node.js) Azure Key Vault Sign with a Certificate's Private Key

See more Azure Key Vault Examples

Signs a hash using the private key of a certificate previously imported to an Azure Key Vault.

Note: This example requires Chilkat v9.5.0.96 or later.

For more information, see https://learn.microsoft.com/en-us/rest/api/keyvault/certificates/import-certificate/import-certificate?tabs=HTTP

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

    // This requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // See Azure Key Vault Get Certificates for a more detailed explanation
    // for how Chilkat is automatically getting the OAuth2 access token for your application.

    var success;

    // Provide information needed for Chilkat to automatically get an OAuth2 access token as needed.
    var json = new chilkat.JsonObject();
    json.UpdateString("client_id","APP_ID");
    json.UpdateString("client_secret","APP_PASSWORD");
    json.UpdateString("resource","https://vault.azure.net");
    json.UpdateString("token_endpoint","https://login.microsoftonline.com/TENANT_ID/oauth2/token");

    // In this example, we'll sign the SHA256 hash of the string "This is a test"
    var sb = new chilkat.StringBuilder();
    var signedString = "This is a test";
    sb.Append(signedString);
    var hash_base64url = sb.GetHash("sha256","base64url","utf-8");

    // We're going to send a POST to the following URL:
    // POST {vaultBaseUrl}/keys/{key-or-cert-name}/{key-or-cert-version}/sign?api-version=7.4

    // For example:

    // POST https://VAULT_NAME.vault.azure.net/keys/CERT_NAME/CERT_VERSION/sign?api-version=7.4
    // 
    // {
    //   "alg": "RS512",
    //   "value": "RUE3Nzg4NTQ4QjQ5RjFFN0U2NzAyQzhDNEMwMkJDOTA1MTYyOTUzNjI5NDhBNzZDQTlFOTM1NDA2M0ZGMjk2Mg"
    // }

    // The alg can be one of the following
    // ES256  ECDSA using P-256 and SHA-256
    // ES256K ECDSA using P-256K and SHA-256
    // ES384  ECDSA using P-384 and SHA-384
    // ES512  ECDSA using P-521 and SHA-512
    // PS256  RSASSA-PSS using SHA-256 and MGF1 with SHA-256
    // PS384  RSASSA-PSS using SHA-384 and MGF1 with SHA-384
    // PS512  RSASSA-PSS using SHA-512 and MGF1 with SHA-512
    // RS256  RSASSA-PKCS1-v1_5 using SHA-256
    // RS384  RSASSA-PKCS1-v1_5 using SHA-384
    // RS512  RSASSA-PKCS1-v1_5 using SHA-512

    // The sample POST above uses SHA512.  We'll instead sign a SHA256 hash..

    var jsonBody = new chilkat.JsonObject();
    jsonBody.UpdateString("alg","RS256");
    jsonBody.UpdateString("value",hash_base64url);

    var http = new chilkat.Http();

    // Instead of providing an actual access token, we give Chilkat the information that allows it to 
    // automatically fetch the access token using the OAuth2 client credentials flow.
    http.AuthToken = json.Emit();

    http.SetUrlVar("certName","importCert01");
    http.SetUrlVar("certVersion","7140c8755ed14839b5d86a9f7e7f0497");
    // Note: Replace "VAULT_NAME" with the name of your Azure key vault.
    var url = "https://VAULT_NAME.vault.azure.net/keys/{$certName}/{$certVersion}/sign?api-version=7.4";
    // resp: HttpResponse
    var resp = http.PostJson3(url,"application/json",jsonBody);
    if (http.LastMethodSuccess == false) {
        // This means something failed before we got a response.
        console.log(http.LastErrorText);
        return;
    }

    var statusCode = resp.StatusCode;

    var jsonResp = new chilkat.JsonObject();
    resp.GetBodyJson(jsonResp);

    jsonResp.EmitCompact = false;
    console.log(jsonResp.Emit());

    if (statusCode !== 200) {
        console.log("Failed.");
        return;
    }

    // A successful response body contains JSON like this:
    // Note: Azure's documentation is not very clear, but base64url is the encoding, not "base64".
    // {
    //   "kid": "https://kvchilkat.vault.azure.net/keys/importCert01/7140c8755ed14839b5d86a9f7e7f0497",
    //   "value": "JzWd2YF21gjtW ... Em37hKOQ"
    // }

    // Let's validate the signature using the cert's public key.
    // This example will load the corresponding certificate from a local file and will verify the signature against the original data.
    // 
    var cert = new chilkat.Cert();
    success = cert.LoadFromFile("qa_data/certs/chilkat_code_signing_2024.cer");
    if (success == false) {
        console.log(cert.LastErrorText);
        return;
    }

    var rsa = new chilkat.Rsa();
    // Tell the RSA object to use the cert's public key.
    success = rsa.SetX509Cert(cert,false);
    if (success == false) {
        console.log(rsa.LastErrorText);
        return;
    }

    // Verify the signature using the cert's public key against the original string.
    rsa.EncodingMode = "base64url";
    var valid = rsa.VerifyStringENC(signedString,"sha-256",jsonResp.StringOf("value"));
    console.log("signature valid = " + valid);

}

chilkatExample();