(Xojo Plugin) Get a Certificate's Key Size

Demonstrates how to get the RSA key size of a certificate (for example, 1024-bit, 2048-bit, etc.)

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

//  For this example, I have a certificate in raw base64 format (not PEM),
//  that looks like this:  "MIIGkDCCBHigAwIBAgIUMDA ... s/iqLsLA=="
Dim sbCertBase64 As New Chilkat.StringBuilder
Dim success As Boolean
success = sbCertBase64.LoadFile("qa_data/certs/base64Cert.txt","utf-8")

Dim cert As New Chilkat.Cert
success = cert.LoadFromBase64(sbCertBase64.GetAsString())
If (success <> True) Then
    System.DebugLog(cert.LastErrorText)
    Return
End If

//  Get the public key.
Dim pubKey As Chilkat.PublicKey
pubKey = cert.ExportPublicKey()
If (cert.LastMethodSuccess <> True) Then
    System.DebugLog(cert.LastErrorText)
    Return
End If

//  In Chilkat version v9.5.0.67, the KeySize property was added.
Dim numBits As Int32
numBits = pubKey.KeySize
System.DebugLog("Number of bits = " + Str(numBits))

//  If using an older version of Chilkat, the key size can be obtained like this:
Dim xml As New Chilkat.Xml
success = xml.LoadXml(pubKey.GetXml())

Dim binDat As New Chilkat.BinData
success = binDat.AppendEncoded(xml.GetChildContent("Modulus"),"base64")

numBits = 8 * binDat.NumBytes
System.DebugLog("Number of bits = " + Str(numBits))