B4X Requires Chilkat v11.0.0+

RSA Signature with Certificate's Private Key from PFX

See more RSA Examples

Demonstrates how to use a certificate's private key from a PFX file to create an RSA signature. B4X

Dim success As Boolean = False

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

'  Create an instance of a certificate store object, load a PFX file,
'  locate the certificate we need, and use it for signing.
'  (a PFX file may contain more than one certificate.)
Dim certStore As ChilkatCertStore
certStore.Initialize

'  The 1st argument is the filename, the 2nd arg is the 
'  PFX file's password:
success = certStore.LoadPfxFile("chilkat.pfx", "test")
If success = False Then
    Log(certStore.LastErrorText)
    Return
End If


'  Find the certificate by the subject common name:
Dim jsonCN As ChilkatJsonObject
jsonCN.Initialize
jsonCN.UpdateString("CN", "cert common name")

Dim cert As ChilkatCert
cert.Initialize("cert")
success = certStore.FindCert(jsonCN, cert)
If success = False Then
    Log(certStore.LastErrorText)
    Return
End If


Dim privKey As ChilkatPrivateKey
privKey.Initialize("privKey")
success = cert.GetPrivateKey(privKey)
If success = False Then
    Log(cert.LastErrorText)
    Return
End If


Dim rsa As ChilkatRsa
rsa.Initialize

success = rsa.UsePrivateKey(privKey)
If success = False Then
    Log(rsa.LastErrorText)
    Return
End If


'  Encode the signature as a hex string
rsa.EncodingMode = "hex"

Dim strData As String = "This is the string to be signed."

'  Sign the string using the sha-1 hash algorithm.
'  Other valid choices are "sha-256", "md2" and "md5".
Dim hexSig As String = rsa.SignStringENC(strData, "sha-1")

Log(hexSig)

Log("Success!")