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Encryption

Created by Johan van der Knijff on Jul 15, 2013 · last edited by Johan van der Knijff · on Jul 15, 2013 (view history) · 22 versions

Description

PDF permits the use of encryption as a means of restricting access or (re-)use of content. This may range from documents that can only be opened after providing a password, to disabling specific functionality (e.g. printing, copying content).

Risks

Content may become inaccessible if passwords are not known (even though "cracking" is often technically possible, institutions may not be legally permitted to do this)
Printing / copy restrictions may complicated any future preservation actions

Assessment

The Preflight component of Apache PDFBox (an open source PDF/A validator) is able to detect encryption in a PDF (any PDF, doesn't have to be PDF/A!).

PDF requires password for opening

In Preflight 1.8.0 an open password results in error code 1.0 (syntax error) with the following accompanying description:

Syntax error, Error (CryptographyException) while creating security handler for decryption: Error: The supplied password does not match either the owner or user password in the document

In Preflight 2.0.0 only a 'syntax' error message is reported without any indication of anything encryption-related. Reported this as a bug

Error code

Affected if expression returns True

Tool	Affected if expression returns True
[Apache+PDFBox]	`"/preflight/errors/error/code = '1.0' and /preflight/errors/error/details = 'Syntax error, Error (CryptographyException) while creating security handler for decryption: Error: The supplied password does not match either the owner or user password in the document'"`

Recommendations

Recommendations on what action(s) to pursue in case file is affected by this problem. Optional.

Example files

Links to example files, preferrably from OPF Format Corpus, e.g. like this:

http://www.opf-labs.org/format-corpus/jp2k-test/resolution/balloon_aware.jp2 - Sample file Aware 3.19 (Capture Resolution)

References

References to literature, etc.