diff options
Diffstat (limited to 'manual')
-rw-r--r-- | manual/qpdf-manual.xml | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/manual/qpdf-manual.xml b/manual/qpdf-manual.xml index b006a4ef..8c8f4d5b 100644 --- a/manual/qpdf-manual.xml +++ b/manual/qpdf-manual.xml @@ -379,6 +379,35 @@ make </listitem> </varlistentry> <varlistentry> + <term><option>--password-is-hex-key</option></term> + <listitem> + <para> + Overrides the usual computation/retrieval of the PDF file's + encryption key from user/owner password with an explicit + specification of the encryption key. When this option is + specified, the argument to the <option>--password</option> + option is interpreted as a hexadecimal-encoded key value. This + only applies to the password used to open the main input file. + It does not apply to other files opened by + <option>--pages</option> or other options or to files being + written. + </para> + <para> + Most users will never have a need for this option, and no + standard viewers support this mode of operation, but it can be + useful for forensic or investigatory purposes. For example, if + a PDF file is encrypted with an unknown password, a + brute-force attack using the key directly is sometimes more + efficient than one using the password. Also, if a file is + heavily damaged, it may be possible to derive the encryption + key and recover parts of the file using it directly. To expose + the encryption key used by an encrypted file that you can open + normally, use the <option>--show-encryption-key</option> + option. + </para> + </listitem> + </varlistentry> + <varlistentry> <term><option>--rotate=[+|-]angle:page-range</option></term> <listitem> <para> @@ -1285,6 +1314,24 @@ outfile.pdf</option> </listitem> </varlistentry> <varlistentry> + <term><option>--show-encryption-key</option></term> + <listitem> + <para> + When encryption information is being displayed, as when + <option>--check</option> or <option>--show-encryption</option> + is given, display the computed or retrieved encryption key as + a hexadecimal string. This value is not ordinarily useful to + users, but it can be used as the argument to + <option>--password</option> if the + <option>--password-is-hex-key</option> is specified. Note + that, when PDF files are encrypted, passwords and other + metadata are used only to compute an encryption key, and the + encryption key is what is actually used for encryption. This + enables retrieval of that key. + </para> + </listitem> + </varlistentry> + <varlistentry> <term><option>--check-linearization</option></term> <listitem> <para> @@ -2936,6 +2983,50 @@ print "\n"; </para> <variablelist> <varlistentry> + <term>7.1.0: January 14, 2018</term> + <listitem> + <itemizedlist> + <listitem> + <para> + PDF files contain streams that may be compressed with various + compression algorithms which, in some cases, may be enhanced + by various predictor functions. Previously only the PNG up + predictor was supported. In this version, all the PNG + predictors as well as the TIFF predictor are supported. This + increases the range of files that qpdf is able to handle. + </para> + </listitem> + <listitem> + <para> + QPDF now allows a raw encryption key to be specified in place + of a password when opening encrypted files, and will + optionally display the encryption key used by a file. This is + a non-standard operation, but it can be useful in certain + situations. Please see the discussion of + <option>--password-is-hex-key</option> in <xref + linkend="ref.basic-options"/> or the comments around + <function>QPDF::setPasswordIsHexKey</function> in + <filename>QPDF.hh</filename> for additional details. + </para> + </listitem> + <listitem> + <para> + Bug fix: numbers ending with a trailing decimal point are now + properly recognized as numbers. + </para> + </listitem> + <listitem> + <para> + Bug fix: when building qpdf from source on some platforms + (especially MacOS), the build could get confused by older + versions of qpdf installed on the system. This has been + corrected. + </para> + </listitem> + </itemizedlist> + </listitem> + </varlistentry> + <varlistentry> <term>7.0.0: September 15, 2017</term> <listitem> <itemizedlist> |