B4X Requires Chilkat v11.0.0+

Get a Certificate's Key Size

See more Certificates Examples

Demonstrates how to get the RSA key size of a certificate (for example, 1024-bit, 2048-bit, etc.) B4X

Dim success As Boolean = False

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

Dim cert As ChilkatCert
cert.Initialize("cert")
success = cert.LoadFromBase64(sbCertBase64.GetAsString)
If success = False Then
    Log(cert.LastErrorText)
    Return
End If


'  Get the public key.
Dim pubKey As ChilkatPublicKey
pubKey.Initialize
cert.GetPublicKey(pubKey)

Dim numBits As Int = pubKey.KeySize
Log("Number of bits = " & numBits)

'  If using an older version of Chilkat, the key size can be obtained like this:
Dim xml As ChilkatXml
xml.Initialize
xml.LoadXml(pubKey.GetXml)

Dim binDat As ChilkatBinData
binDat.Initialize
binDat.AppendEncoded(xml.GetChildContent("Modulus"), "base64")

numBits = 8 * binDat.NumBytes
Log("Number of bits = " & numBits)