(Xojo Plugin) RSA Sign an Encoded Hash

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Demonstrates signing a hash (e.g., SHA256) provided as an encoded string (e.g., base64 or hex).

Chilkat Xojo Plugin Download

Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

// 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 Chilkat.Cert

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

// Specify the certificate by its common name.
Dim success As Boolean
success = cert.LoadFromSmartcard("cn=chilkat-rsa-2048")
If (success = False) Then
    System.DebugLog(cert.LastErrorText)
    Return
End If

System.DebugLog("Signing with the private key for this cert: " + cert.SubjectCN)

// Create data to be hashed and signed.
Dim bd As New Chilkat.BinData
Dim i As Int32
For i = 0 To 100
    success = bd.AppendEncoded("000102030405060708090A0B0C0D0E0F","hex")
Next

Dim rsa As New Chilkat.Rsa

// Use the certificate's private key for signing.
success = rsa.SetX509Cert(cert,True)
If (success = False) Then
    System.DebugLog(rsa.LastErrorText)
    Return
End If

// We'll first compute the hash and then pass the encoded hash to be signed.
Dim sha256_base64 As String
sha256_base64 = bd.GetHash("sha256","base64")
System.DebugLog("sha256 hash in base64 format: " + sha256_base64)

// Pass in the base64 hash and return a base64 signature.
rsa.EncodingMode = "base64"
Dim rsaSig_base64 As String
rsaSig_base64 = rsa.SignHashENC(sha256_base64,"sha256")
If (success = False) Then
    System.DebugLog(rsa.LastErrorText)
    Return
End If

System.DebugLog("RSA signature as base64: " + rsaSig_base64)