VB.NET

RSA Hash Binary Data and Sign (and Verify)

See more RSA Examples

Demonstrates how to sign the hash of binary data. Also demonstrates how to verify the RSA signature. VB.NET

Dim success As Boolean = False

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

' Load an RSA private key for signing.
Dim privKey As New Chilkat.PrivateKey
success = privKey.LoadEncryptedPemFile("qa_data/pem/rsa_passwd.pem","passwd")
If (success = False) Then
    Debug.WriteLine(privKey.LastErrorText)
    Exit Sub
End If


Dim rsa As New Chilkat.Rsa
rsa.UsePrivateKey(privKey)

' We have some binary data (in hex) to sign
Dim originalData As String = "0102030405060708090A"
Dim bdData As New Chilkat.BinData
bdData.AppendEncoded(originalData,"hex")

' Hash (SHA-256) and sign the hash:
Dim bdSignature As New Chilkat.BinData
success = rsa.SignBd(bdData,"sha256",bdSignature)
If (success = False) Then
    Debug.WriteLine(rsa.LastErrorText)
    Exit Sub
End If


' Show the RSA signature in base64
Debug.WriteLine(bdSignature.GetEncoded("base64"))

' ------------------------------------------
' Get the public key from the private key
Dim pubKey As New Chilkat.PublicKey
privKey.ToPublicKey(pubKey)

' Verify the signature..
Dim rsa2 As New Chilkat.Rsa
rsa2.UsePublicKey(pubKey)

Dim bVerified As Boolean = rsa2.VerifyBd(bdData,"sha256",bdSignature)
Debug.WriteLine("signature verified: " & bVerified)