How to serialize and deserialize a PFX certificate in Azure Key Vault?

Question

I have a bunch of strings and pfx certificates, which I want to store in Azure Key vault, where only allowed users/apps will be able to get them. It is not hard to do store

Answer 1

Here is how I solved this. First, convert your PFX file to a base64 string. You can do that with these two simple PowerShell commands:

$fileContentBytes = get-content 'certificate.pfx' -Encoding Byte
[System.Convert]::ToBase64String($fileContentBytes) | Out-File 'certificate_base64.txt'

Create a secret in Azure Key Vault via the Azure Portal. Copy the certificate base64 string that you created previously and paste it in the secret value field in your Azure Key Vault via the Azure Portal. Then simply call the Azure Key Vault from the code to get the base64 string value and convert that to a X509Certificate2:

private async Task GetCertificateAsync()
{
    var azureServiceTokenProvider = new AzureServiceTokenProvider();
    var keyVaultClient = new KeyVaultClient(new KeyVaultClient.AuthenticationCallback(azureServiceTokenProvider.KeyVaultTokenCallback));
    var secret = await keyVaultClient.GetSecretAsync("https://path/to/key/vault").ConfigureAwait(false);
    var pfxBase64 = secret.Value;
    var bytes = Convert.FromBase64String(pfxBase64);
    var coll = new X509Certificate2Collection();
    coll.Import(bytes, "certificatePassword", X509KeyStorageFlags.Exportable);
    return coll[0];
}