(Visual Basic 6.0) RSA Sign utf-8 Bytes of String to get Base64 RSA Signature

See more Apple Keychain Examples

Demonstrates how RSA sign the utf-8 byte representation of a string to get the signature in base64 format.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

' 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.
Dim success As Long
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 a string to be hashed and signed.
Dim sb As New ChilkatStringBuilder
Dim crlfLineEnding As Long
crlfLineEnding = 1
Dim i As Long
For i = 0 To 10
    success = sb.AppendLine("This is a test.",crlfLineEnding)
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 utf-8 byte representation of the contents of sb
' Return the signature in base64 format.
rsa.EncodingMode = "base64"
rsa.Charset = "utf-8"
Dim stringToSign As String
stringToSign = sb.GetAsString()
Dim sigBase64 As String
sigBase64 = rsa.SignStringENC(stringToSign,"sha256")
If (rsa.LastMethodSuccess = 0) Then
    Debug.Print rsa.LastErrorText
    Exit Sub
End If

Debug.Print "RSA signature as base64: " & sigBase64