B4X

Sign PDF using PAdES-Baseline-B

See more PDF Signatures Examples

PAdES-Baseline-B is the most basic, entry-level profile of the PDF Advanced Electronic Signatures (PAdES) standard.

It means:

• A PDF contains a CMS/PKCS#7 detached signature over the document’s byte range.
• /SubFilter must be ETSI.CAdES.detached.
• The signer’s X.509 certificate is included inside the signature.
• The signature uses recognized secure algorithms (e.g., SHA-256 with RSA/ECDSA).
• It proves document integrity (no changes since signing) and signer authenticity (certificate identifies who signed).
• It does not include time-stamps, revocation data (CRL/OCSP), or long-term validation information — those appear only in higher levels (PAdES-Baseline-T, -LT, -LTA).

In short: Baseline-B = a standard PDF digital signature that ensures integrity and origin, but without time or revocation guarantees.

B4X

Dim success As Boolean = False

Dim pdf As ChilkatPdf
pdf.Initialize("pdf")

'  Load a PDF to be signed.
success = pdf.LoadFile("c:/someDir/my.pdf")
If success = False Then
    Log(pdf.LastErrorText)
    Return
End If


'  Options for signing are specified in JSON.
Dim json As ChilkatJsonObject
json.Initialize

json.UpdateString("subFilter", "/ETSI.CAdES.detached")
json.UpdateBool("signingCertificateV2", True)
json.UpdateBool("signingTime", True)
json.UpdateString("signingAlgorithm", "pkcs")
json.UpdateString("hashAlgorithm", "sha256")

'  -----------------------------------------------------------
'  The following JSON settings define the signature appearance.
json.UpdateInt("page", 1)
json.UpdateString("appearance.y", "top")
json.UpdateString("appearance.x", "left")
json.UpdateString("appearance.fontScale", "10.0")
json.UpdateString("appearance.text[0]", "Digitally signed by: cert_cn")
json.UpdateString("appearance.text[1]", "current_dt")
json.UpdateString("appearance.text[2]", "Hello 123 ABC")

'  --------------------------------------------------------------
'  Load the signing certificate. (Use your own certificate.)
'  Note: There are other methods for using a certificate on an HSM (smartcard or token)
'  or from other sources, such as a cloud HSM, a Windows installed certificate,
'  or other file formats.
Dim cert As ChilkatCert
cert.Initialize("cert")
success = cert.LoadPfxFile("c:/myPfxFiles/myPdfSigningCert.pfx", "pfxPassword")
If success = False Then
    Log(cert.LastErrorText)
    Return
End If


'  Once we have the certificate object, tell the PDF object to use it for signing
success = pdf.SetSigningCert(cert)
If success = False Then
    Log(pdf.LastErrorText)
    Return
End If


'  Sign the PDF, creating the output file.
Dim outFilePath As String = "c:/someDir/mySigned.pdf"
success = pdf.SignPdf(json, outFilePath)
If success = False Then
    Log(pdf.LastErrorText)
    Return
End If


Log("Success.")