Visual Basic 6.0

RSA Sign using a Private Key on a USB Token or Smartcard

See more Apple Keychain Examples

Create an RSA signature using a private key stored on a USB token or smartcard.

Note: On MacOS and iOS, this example requires Chilkat v10.1.2 or later when the Apple Keychain is used as the underlying means to do the signing.

Visual Basic 6.0

Dim success As Long
success = 0

' Assuming the smartcard/USB token is installed with the correct drivers from the manufacturer,
' this code can work on multiple platforms including Windows, MacOS, Linux, and iOS.

' Chilkat automatically detects and determines the way in which the HSM is used,
' which can be by PKCS11, Apple Keychain, Microsoft CNG / Crypto API, or ScMinidriver.

Dim cert As New ChilkatCert

' Set the token/smartcard PIN prior to loading.
cert.SmartCardPin = "123456"

' Specify the certificate by its common name.
success = cert.LoadFromSmartcard("cn=chilkat-rsa-2048")
If (success = 0) Then
    Debug.Print cert.LastErrorText
    Exit Sub
End If

Debug.Print "Signing with cert: " & cert.SubjectCN

' Create data to be hashed and signed.
Dim bd As New ChilkatBinData
Dim i As Long
For i = 0 To 100
    success = bd.AppendEncoded("000102030405060708090A0B0C0D0E0F","hex")
Next

Dim rsa As New ChilkatRsa

' Use the certificate's private key for signing.
success = rsa.SetX509Cert(cert,1)
If (success = 0) Then
    Debug.Print rsa.LastErrorText
    Exit Sub
End If

' Sign the SHA-256 hash of the contents of bd.
Dim bdSig As New ChilkatBinData
success = rsa.SignBd(bd,"sha256",bdSig)
If (success = 0) Then
    Debug.Print rsa.LastErrorText
    Exit Sub
End If

' The RSA signature is equal in length to the size of the RSA key.
Debug.Print "Output signature size in bits = " & (bdSig.NumBytes * 8)

' We can save the signature for later verification..
success = bdSig.WriteFile("rsaSignatures/test1.sig")

' See the example to verify the RSA signature:
' Verfies an RSA Signature