Xbase++ Requires Chilkat v11.0.0+

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. Xbase++

LOCAL nSuccess
LOCAL oJson
LOCAL oSb
LOCAL cSignedString
LOCAL cHash_base64url
LOCAL oJsonBody
LOCAL oHttp
LOCAL cUrl
LOCAL oResp
LOCAL nStatusCode
LOCAL oJsonResp
LOCAL oCert
LOCAL oRsa
LOCAL nValid

nSuccess := 0

//  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.
oJson := CreateObject("Chilkat.JsonObject")
oJson:UpdateString("client_id", "APP_ID")
oJson:UpdateString("client_secret", "APP_PASSWORD")
oJson:UpdateString("resource", "https://vault.azure.net")
oJson: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"
oSb := CreateObject("Chilkat.StringBuilder")
cSignedString := "This is a test"
oSb:Append(cSignedString)
cHash_base64url := oSb: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..

oJsonBody := CreateObject("Chilkat.JsonObject")
oJsonBody:UpdateString("alg", "RS256")
oJsonBody:UpdateString("value", cHash_base64url)

oHttp := CreateObject("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.
oHttp:AuthToken := oJson:Emit()

oHttp:SetUrlVar("certName", "importCert01")
oHttp:SetUrlVar("certVersion", "7140c8755ed14839b5d86a9f7e7f0497")
//  Note: Replace "VAULT_NAME" with the name of your Azure key vault.
cUrl := "https://VAULT_NAME.vault.azure.net/keys/{$certName}/{$certVersion}/sign?api-version=7.4"
oResp := CreateObject("Chilkat.HttpResponse")
nSuccess := oHttp:HttpJson("POST", cUrl, oJsonBody, "application/json", oResp)
IF (nSuccess == 0)
    ? oHttp:LastErrorText
    oJson:destroy()
    oSb:destroy()
    oJsonBody:destroy()
    oHttp:destroy()
    oResp:destroy()
    RETURN
ENDIF

nStatusCode := oResp:StatusCode

oJsonResp := CreateObject("Chilkat.JsonObject")
oResp:GetBodyJson(oJsonResp)

oJsonResp:EmitCompact := 0
? oJsonResp:Emit()

IF (nStatusCode != 200)
    ? "Failed."
    oJson:destroy()
    oSb:destroy()
    oJsonBody:destroy()
    oHttp:destroy()
    oResp:destroy()
    oJsonResp:destroy()
    RETURN
ENDIF

//  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.
//  
oCert := CreateObject("Chilkat.Cert")
nSuccess := oCert:LoadFromFile("qa_data/certs/chilkat_code_signing_2024.cer")
IF (nSuccess == 0)
    ? oCert:LastErrorText
    oJson:destroy()
    oSb:destroy()
    oJsonBody:destroy()
    oHttp:destroy()
    oResp:destroy()
    oJsonResp:destroy()
    oCert:destroy()
    RETURN
ENDIF

oRsa := CreateObject("Chilkat.Rsa")
//  Tell the RSA object to use the cert's public key.
nSuccess := oRsa:SetX509Cert(oCert, 0)
IF (nSuccess == 0)
    ? oRsa:LastErrorText
    oJson:destroy()
    oSb:destroy()
    oJsonBody:destroy()
    oHttp:destroy()
    oResp:destroy()
    oJsonResp:destroy()
    oCert:destroy()
    oRsa:destroy()
    RETURN
ENDIF

//  Verify the signature using the cert's public key against the original string.
oRsa:EncodingMode := "base64url"
nValid := oRsa:VerifyStringENC(cSignedString, "sha-256", oJsonResp:StringOf("value"))
? "signature valid = " + Str(nValid)

oJson:destroy()
oSb:destroy()
oJsonBody:destroy()
oHttp:destroy()
oResp:destroy()
oJsonResp:destroy()
oCert:destroy()
oRsa:destroy()