Xojo Plugin

Verify an RSA Signature Against the Signed Hash

See more Apple Keychain Examples

Demonstrates how to validate an RSA Signature against the hash that was signed. Xojo Plugin

Dim success As Boolean
success = False

Dim bd As New Chilkat.BinData
Dim i As Int32
For i = 0 To 100
    success = bd.AppendEncoded("000102030405060708090A0B0C0D0E0F","hex")
Next
Dim sha256_base64 As String
sha256_base64 = bd.GetHash("sha256","base64")
System.DebugLog("sha256 hash in base64 format: " + sha256_base64)

Dim base64_rsa_sig As String
base64_rsa_sig = "AwF2BbOvL6jA5DwmMAc9n6J2Cc8PI6Rj5W079+aKJcIEtPWRzHor0Bvc3aftGM3Jbgj6SXlIC3M3RYS7UZOnfiHKFNZgbxaNT5WwsWooK42ZkC8DBZl0p7OunBUKd5SciUo+TKilioeUkriN3L1Zl9hwi3HVDVqgVo3XXskwIftSqLSFlepTLTmOWj9Y93dp8J4D9RyLtNgFQBc0WB22tyJTsuY56mLcWe1AMF3LizB9OrbwjynF2u16xWlrJdugccz795fJBUV9aQSD+8S3KeqwQhoi8RK1uhD68aGCyaSpBq0NZ8COAkn7MXaF4POxrAAt8udfHM+PRfSOptcH/w=="

// Get the public key to be used for signature verification.
Dim pubKey As New Chilkat.PublicKey
success = pubKey.LoadFromFile("rsaKeys/chilkat-rsa-2048.pem")
If (success = False) Then
    System.DebugLog(pubKey.LastErrorText)
    Return
End If

Dim rsa As New Chilkat.Rsa
success = rsa.UsePublicKey(pubKey)
If (success = False) Then
    System.DebugLog(rsa.LastErrorText)
    Return
End If

// Verify the hash against the signature.
rsa.EncodingMode = "base64"
success = rsa.VerifyHashENC(sha256_base64,"sha256",base64_rsa_sig)

If (success = False) Then
    System.DebugLog(rsa.LastErrorText)
    System.DebugLog("Signature invalid.")
Else
    System.DebugLog("Signature valid.")
End If