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RSA Sign Binary Data and Verify (Recover the Original Data)

See more RSA Examples

Demonstrates how to RSA sign binary data and then verify/recover the original data.

Note: This example uses methods introduced in Chilkat v9.5.0.77.

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Dim success As Boolean
success = 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
    System.DebugLog(privKey.LastErrorText)
    Return
End If

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

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

// If successful, the contents of bd are replaced with the RSA signature.
success = rsa.SignRawBd(bd)
If (success = False) Then
    System.DebugLog(rsa.LastErrorText)
    Return
End If

// Show the RSA signature in base64
System.DebugLog(bd.GetEncoded("base64"))

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

// Verify the signature and extract the original data.
Dim rsa2 As New Chilkat.Rsa
success = rsa2.UsePublicKey(pubKey)

Dim bVerified As Boolean
bVerified = rsa2.VerifyRawBd(bd)
System.DebugLog("signature verified: " + Str(bVerified))

// Show the original data:
System.DebugLog("original data: " + bd.GetEncoded("hex"))