C
C
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.Chilkat C Downloads
#include <C_CkJsonObject.h>
#include <C_CkStringBuilder.h>
#include <C_CkHttp.h>
#include <C_CkHttpResponse.h>
#include <C_CkCert.h>
#include <C_CkRsa.h>
void ChilkatSample(void)
{
BOOL success;
HCkJsonObject json;
HCkStringBuilder sb;
const char *signedString;
const char *hash_base64url;
HCkJsonObject jsonBody;
HCkHttp http;
const char *url;
HCkHttpResponse resp;
int statusCode;
HCkJsonObject jsonResp;
HCkCert cert;
HCkRsa rsa;
BOOL valid;
success = FALSE;
// 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.
// Provide information needed for Chilkat to automatically get an OAuth2 access token as needed.
json = CkJsonObject_Create();
CkJsonObject_UpdateString(json,"client_id","APP_ID");
CkJsonObject_UpdateString(json,"client_secret","APP_PASSWORD");
CkJsonObject_UpdateString(json,"resource","https://vault.azure.net");
CkJsonObject_UpdateString(json,"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"
sb = CkStringBuilder_Create();
signedString = "This is a test";
CkStringBuilder_Append(sb,signedString);
hash_base64url = CkStringBuilder_getHash(sb,"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..
jsonBody = CkJsonObject_Create();
CkJsonObject_UpdateString(jsonBody,"alg","RS256");
CkJsonObject_UpdateString(jsonBody,"value",hash_base64url);
http = CkHttp_Create();
// 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.
CkHttp_putAuthToken(http,CkJsonObject_emit(json));
CkHttp_SetUrlVar(http,"certName","importCert01");
CkHttp_SetUrlVar(http,"certVersion","7140c8755ed14839b5d86a9f7e7f0497");
// Note: Replace "VAULT_NAME" with the name of your Azure key vault.
url = "https://VAULT_NAME.vault.azure.net/keys/{$certName}/{$certVersion}/sign?api-version=7.4";
resp = CkHttpResponse_Create();
success = CkHttp_HttpJson(http,"POST",url,jsonBody,"application/json",resp);
if (success == FALSE) {
printf("%s\n",CkHttp_lastErrorText(http));
CkJsonObject_Dispose(json);
CkStringBuilder_Dispose(sb);
CkJsonObject_Dispose(jsonBody);
CkHttp_Dispose(http);
CkHttpResponse_Dispose(resp);
return;
}
statusCode = CkHttpResponse_getStatusCode(resp);
jsonResp = CkJsonObject_Create();
CkHttpResponse_GetBodyJson(resp,jsonResp);
CkJsonObject_putEmitCompact(jsonResp,FALSE);
printf("%s\n",CkJsonObject_emit(jsonResp));
if (statusCode != 200) {
printf("Failed.\n");
CkJsonObject_Dispose(json);
CkStringBuilder_Dispose(sb);
CkJsonObject_Dispose(jsonBody);
CkHttp_Dispose(http);
CkHttpResponse_Dispose(resp);
CkJsonObject_Dispose(jsonResp);
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.
//
cert = CkCert_Create();
success = CkCert_LoadFromFile(cert,"qa_data/certs/chilkat_code_signing_2024.cer");
if (success == FALSE) {
printf("%s\n",CkCert_lastErrorText(cert));
CkJsonObject_Dispose(json);
CkStringBuilder_Dispose(sb);
CkJsonObject_Dispose(jsonBody);
CkHttp_Dispose(http);
CkHttpResponse_Dispose(resp);
CkJsonObject_Dispose(jsonResp);
CkCert_Dispose(cert);
return;
}
rsa = CkRsa_Create();
// Tell the RSA object to use the cert's public key.
success = CkRsa_SetX509Cert(rsa,cert,FALSE);
if (success == FALSE) {
printf("%s\n",CkRsa_lastErrorText(rsa));
CkJsonObject_Dispose(json);
CkStringBuilder_Dispose(sb);
CkJsonObject_Dispose(jsonBody);
CkHttp_Dispose(http);
CkHttpResponse_Dispose(resp);
CkJsonObject_Dispose(jsonResp);
CkCert_Dispose(cert);
CkRsa_Dispose(rsa);
return;
}
// Verify the signature using the cert's public key against the original string.
CkRsa_putEncodingMode(rsa,"base64url");
valid = CkRsa_VerifyStringENC(rsa,signedString,"sha-256",CkJsonObject_stringOf(jsonResp,"value"));
printf("signature valid = %d\n",valid);
CkJsonObject_Dispose(json);
CkStringBuilder_Dispose(sb);
CkJsonObject_Dispose(jsonBody);
CkHttp_Dispose(http);
CkHttpResponse_Dispose(resp);
CkJsonObject_Dispose(jsonResp);
CkCert_Dispose(cert);
CkRsa_Dispose(rsa);
}