snowdrop(1) [debian man page]
SNOWDROP(1) General Commands Manual SNOWDROP(1) NAME
sd-eng, sd-engf, sd-c - text watermarking and watermark recovery SYNOPSIS
sd-eng [-6] -i origfile newfile "Recipient" ["Comment"] sd-eng [-6] -e origfile newfile sd-eng [-6] -l DESCRIPTION
snowdrop is a stenographic text watermarking and watermark recovery system. It is composed of three programs: sd-eng Watermark normal English text. sd-engf Watermark fine quality English text, yeilding higher quality output but encoding less information. sd-c Watermark C code. The three programs operate similarly, with the same parameters and usage. The watermark is encoded in using a number of techniques, such as whitespace reformatting, typo insertation, word substitutions, punctuation changes, and for C code, logic reordering, variable name man- gling, etc. The watermark is a md5sum, which is retreivable from as little as 5 or 10 lines of the watermarked document. Even large changes to a medium sized document should not obscure the watermark, as it is stored redundently in multiple independent channels. The three usage modes are adding a watermark, checking for the presense of a watermark, and listing the contents of your database of water- marks. Note that to later check a watermark, you must retain a copy of the original, un-watermarked file. OPTIONS
-i Inject a watermark into a file. You must pass it the original file, the filename to output the watwrmarked version to, information about who you intend the watermarked file for, and an optional comment. -e Extract a watermark from a file. Needs the original file and the new file that you suspect bears the watermark. -l Lists the contents of the watermark database. Each of the three programs will have a different list. -6 Enable 64 bit watermarking. The default is a weak 32 bit watermark. ENVIRONMENT
SD_SYNONYMS This variable can be used to point snowdrop at a customized synonyms file. FILES
~/.snowdrop/database Database of watermarked files. SEE ALSO
/usr/share/snowdrop/README Explain snowdrop in more depth, its limitations, and how to write additional watermarking modules for other tpyes of files. AUTHOR
Michal Zalewski <lcamtuf@coredump.cx> SNOWDROP(1)
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dat_ep_set_watermark(3DAT) Direct Access Transport Library Functions dat_ep_set_watermark(3DAT) NAME
dat_ep_set_watermark - set high watermark on Endpoint SYNOPSIS
cc [ flag... ] file... -ldat [ library... ] #include <dat/udat.h> DAT_RETURN dat_ep_set_watermark ( IN DAT_EP_HANDLE ep_handle, IN DAT_COUNT soft_high_watermark, IN DAT_COUNT hard_high_watermark ) PARAMETERS
ep_handle The handle for an instance of an Endpoint. soft_high_watermark The soft high watermark for the number of Recv buffers consumed by the Endpoint. hard_high_watermark The hard high watermark for the number of Recv buffers consumed by the Endpoint. DESCRIPTION
The dat_ep_set_watermark() function sets the soft and hard high watermark values for EP and arms EP for generating asynchronous events for high watermarks. An asynchronous event will be generated for IA async_evd when the number of Recv buffers at EP exceeds the soft high watermark for the first time. A connection broken event will be generated for EP connect_evd when the number of Recv buffers at EP exceeds the hard high watermark. These can occur during this call or when EP takes a buffer from the SRQ or EP RQ. The soft and hard high watermark asynchronous event generation and setting are independent of each other. The asynchronous event for a soft high watermark is generated only once per setting. Once an event is generated, no new asynchronous events for the soft high watermark is generated until the EP is again set for the soft high watermark. If the Consumer is once again interested in the event, the Consumer should again set the soft high watermark. If the Consumer is not interested in a soft or hard high watermark, the value of DAT_WATERMARK_INFINITE can be specified for the case that is the default value. This value specifies that a non-asynchronous event will be generated for a high watermark EP attribute for which this value is set. It does not prevent generation of a connection broken event for EP when no Recv buffer is available for a message arrived on the EP connection. The operation is supported for all states of Endpoint. RETURN VALUES
DAT_SUCCESS The operation was successful. DAT_INVALID_HANDLE The ep_handle argument is an invalid DAT handle. DAT_INVALID_PARAMETER One of the parameters is invalid. DAT_MODEL_NOT_SUPPORTED The requested Model was not supported by the Provider. The Provider does not support EP Soft or Hard High Water- marks. USAGE
For a hard high watermark, the Provider is ready to generate a connection broken event as soon as the connection is established. If the asynchronous event for a soft or hard high watermark has not yet been generated, this call simply modifies the values for these attributes. The Provider remains armed for generation of these asynchronous events. Regardless of whether an asynchronous event for the soft and hard high watermark has been generated, this operation will set the generation of an asynchronous event with the Consumer-provided high watermark values. If the new high watermark values are below the current number of Receive DTOs at EP, an asynchronous event will be generated immediately. Otherwise the old soft or hard (or both) high watermark values are simply replaced with the new ones. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard: uDAPL, 1.2 | +-----------------------------+-----------------------------+ |MT-Level |Unsafe | +-----------------------------+-----------------------------+ SEE ALSO
dat_ep_create(3DAT), dat_ep_recv_query(3DAT), dat_srq_create(3DAT), dat_srq_free(3DAT), dat_srq_post_recv(3DAT), dat_srq_query(3DAT), dat_srq_resize(3DAT), dat_srq_set_lw(3DAT), libdat(3LIB), attributes(5) SunOS 5.11 16 Jul 2004 dat_ep_set_watermark(3DAT)