+
Installing signatures
+ Information on signature development and syntax can be found below. Once you
+ have something ready to go you can use signatures from this utility in DROID
+ and Siegfried.
+
+
DROID
+ DROID signatures need to be installed in the
.droid6 folder in
+ either Windows or Linux. On Windows this folder will be in
%HOMEPATH%,
+ e.g.
\user\{{username}}. And in Linux
/home/{{username]}/.droid6.
+ Standard signatures are installed in
signature_files and container signature
+ files are installed in
container_sigs.
+
+ When you run the DROID user interface you can navigate to
tools -> preferences to
+ then select your new development signature files.
+
+
Siegfried
+ Similarly for Siegfried, there is a siegfried home directory. Using the above
+ pattern, the siegfried example on Linux will be:
/home/{{username}}/siegfried.
+
+ You simply need to have the two Signature files in this directory and then
+ run the following using Siegfried's
roy tool:
+
+
$ roy build -droid {{your-signature-file-name}}.xml \
+ -noreports \
+ -container {{your-container-signature-file-name}}.xml
+
+
A brief note about container signatures
+ If you are developing a container signature for a format already recorded in
+ PRONOM you only need to worry about creating and using a container signature
+ file from this utility. It is only for novel formats you may consider writing
+ a standard signature file too.
+
+
Syntax
+
Container signatures
+ More information on
+ DROID container signatures.
+
+
+ Additional
container signature syntax.
+
+
Standard signatures
+ More information on DROID signatures and their syntax:
+
+
+ In PRONOM, an internal signature is composed of one or more byte
+ sequences, each comprising a continuous sequence of hexadecimal
+ bytes values and, optionally, regular expressions. A signature byte
+ sequence is modelled by describing its starting position within a
+ bitstream and its value.
+
+ The starting position can be one of two basic types:
+
+ Absolute: The byte sequence starts at a fixed position within the
+ bitstream. The position is described as an offset from either the
+ beginning or the end of the bitstream. The byte sequence can
+ therefore be located by moving to the specified offset, counting
+ from either the beginning of file or end of file position. If
+ counting from either the EOF position, the offset is to the final
+ byte in the sequence.
+
+ Variable: The byte sequence can start at any offset within the
+ bitstream. The byte sequence can be located by examining the entire
+ bitstream.
+
+ The value of the byte sequence is defined as a sequence of
+ hexadecimal values, optionally incorporating any of the following
+ regular expressions:
+
+
+ -
+ ??: wildcard matching any pair of hexadecimal values (i.e. a
+ single byte).
+
+
+ -
+ e.g.: 0x0A FF ?? FE would match 0x0A FF 6C FE or 0x0A FF 11 FE.
+
+
+ -
+ *: wildcard matching any number of bytes (0 or more).
+
+
+ -
+ e.g.: 0x0A FF * FE would match 0x0A FF 6C FE or 0x0A FF 6C 11 FE.
+
+
+ -
+ {n}: wildcard matching n bytes, where n is an integer.
+
+
+ -
+ e.g.: 0x1C 20 {2} 4E 12 would match 0x1C 20 FF 15 4E 12.
+
+
+ -
+ {m-n}: wildcard matching between m-n bytes inclusive, where
+ m and n are integers or ‘*’.
+
+
+ -
+ e.g.: 0x03 {1-2} 4D would match 0x03 3C 4D or 0x03 3C 88 4D.
+
+ e.g.: 0x03 {2-*} 4D would match 0x03 3C 88 4D or 0x03 3C 88 3F 4D.
+
+
+ -
+ (a|b): wildcard matching one from a list of values (e.g. a
+ or b), where each value is a hexadecimal byte sequence of arbitrary
+ length containing no wildcards.
+
+
+ -
+ e.g.: 0x0E (FF|FE) 17 would match 0x0E FF 17 or 0x0E FE 17.
+
+
+ -
+ [a:b]: wildcard matching any sequence of bytes which lies
+ lexicographically between a and b, inclusive (where both a and b
+ are byte sequences of the same length, containing no wildcards, and
+ where a is less than b). The endian-ness of a and b are the same
+ as the endian-ness of the signature as a whole.
+
+
+ -
+ e.g. 0xFF [09:0B] FF would match 0xFF 09 FF, 0xFF 0A FF or 0xFF 0B
+ FF.
+
+
+ -
+ [!a]: wildcard matching any sequence of bytes other than a
+ itself (where a is a byte sequence containing no wildcards).
+
+
+ -
+ e.g. 0xFF [!09] FF would match 0xFF 0A FF, but not 0xFF 09 FF.
+ Digital Preservation Technical Paper 1: Automatic Format
+ Identification Using PRONOM and DROID Page 9 of 33
+
+
+ -
+ [!a:b]: wildcard matching any sequence of bytes which does
+ not lie lexicographically between a and b, inclusive (where a and
+ b are both byte sequences of the same length, containing no
+ wildcards, and where a is less than b).
+
+
+ -
+ e.g. 0xFF [!01:02] FF would match 0xFF 00 FF and 0xFF 03 FF, but
+ not 0xFF 01 FF or 0xFF 02 FF.
+
+
+ Note: In the examples above, spaces are included between byte
+ values for reasons of clarity, but are omitted in actual byte
+ sequence values. The signature is processed left-to-right if the
+ signature is measured relative to BOF and right-to-left if measured
+ relative to EOF. The endian-ness of the signature is only relevant
+ for sequences inside square brackets. A byte sequence must contain
+ a fixed subsequence of at least one byte between each occurrence of
+ ‘*’, or between the beginning or end of the sequence and an
+ occurrence of ‘*’. Thus, sequences of the following form are not
+ permitted:
+
+ [BOF] (a|b)*…
+
+ …*(a|b) [EOF]
+
+ …*(a|b)*...
+
+
Please help improve this resource by visiting
+
+ GitHub and making a pull-request there.
+
+
+