pdfsig - Man Page

Portable Document Format (PDF) digital signatures tool


pdfsig [options] [PDF-file] [Output-file]


pdfsig verifies the digital signatures in a PDF document. It also displays the identity of each signer (commonName field and full distinguished name of the signer certificate), the time and date of the signature, the hash algorithm used for signing, the type of the signature as stated in the PDF and the signed ranges with a statement wether the total document is signed. It can also sign PDF documents (options -add-signature or -sign).

pdfsig uses the trusted certificates stored in the Network Security Services (NSS) Database.

pdfsig also uses the Online Certificate Status Protocol (OCSP) (refer to http://en.wikipedia.org/wiki/Online_Certificate_Status_Protocol) to look up the certificate online and check if it has been revoked (unless -no-ocsp has been specified).

The NSS Database is searched for in the following locations:


-nssdir [prefix]directory

Specify the database directory containing the certificate and key database files. See certutil(1) -d option for details of the prefix. If not specified the other search locations described in Description are used.

-nss-pwd password

Specify the password needed to access the NSS database (if any).


Do not validate the certificate.


Do not perform online OCSP certificate revocation check (local Certificate Revocation Lists (CRL) are still used).


Enable the use of Authority Information Access (AIA) extension to fetch missing certificates to build the certificate chain.


Dump all signatures into current directory in their native format. Most likely it is either a unpadded or zero-padded CMS/PKCS7 bundle.


Add a new signature to the document.

-new-signature-field-name  name

Specifies the field name to be used when adding a new signature. A random ID will be used by default.

-sign  field

Sign the document in the specified signature field present in the document (must be unsigned).  Field can be specified by field name (string) or the n-th signature field in the document (integer).

-nick  nickname

Use the certificate with the given nickname for signing (NSS backend). If nickname starts with pkcs11:, it's treated as PKCS#11 URI (NSS backend). If the nickname is given as a fingerprint, it will be the certificate used (GPG backend)

-backend  backend

Use the specified backeng for cryptographic signatures

-kpw  password

Use the given password for the signing key (this might be missing if the key isn't password protected).

-digest  algorithm

Use the given digest algorithm for signing (default: SHA256).

-reason  reason

Set the given reason string for the signature (default: no reason set).


Create a signature of type ETSI.CAdES.detached instead of adbe.pkcs7.detached.


List available nicknames in the NSS database.


List available backends for cryptographic signatures


Print copyright and version information.


Print usage information. (-help and --help are equivalent.)


pdfsig signed_file.pdf

Displays signature info for signed_file.pdf.

pdfsig input.pdf output.pdf -add-signature -nss-pwd password -nick my-cert -reason 'for fun!'

Creates a new pdf named output.pdf with the contents of input.pdf signed by the 'my-cert' certificate.

pdfsig input.pdf output.pdf -add-signature -nss-pwd password -nick 'pkcs11:token=smartcard0;object=Second%20certificate;type=cert'

Same, but uses a PKCS#11 URI as defined in IETF RFC 7512 to select the certificate to be used for signing.

pdfsig input.pdf output.pdf -sign 0 -nss-pwd password -nick my-cert -reason 'for fun!'

Creates a new pdf named output.pdf with the contents of input.pdf signed by the 'my-cert' certificate. input.pdf must have an already existing un-signed signature field.


The pdfsig software and documentation are copyright 1996-2004 Glyph & Cog, LLC and copyright 2005-2015 The Poppler Developers - http://poppler.freedesktop.org

See Also

pdfdetach(1), pdffonts(1), pdfimages(1), pdfinfo(1), pdftocairo(1), pdftohtml(1), pdftoppm(1), pdftops(1), pdftotext(1) pdfseparate(1), pdfunite(1) certutil(1)

Referenced By

pdfattach(1), pdfdetach(1), pdffonts(1), pdfimages(1), pdfinfo(1), pdfseparate(1), pdftocairo(1), pdftohtml(1), pdftoppm(1), pdftops(1), pdftotext(1), pdfunite(1).

28 October 2015