.\" Copyright (c) 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" This code is derived from software contributed to Berkeley by .\" the Institute of Electrical and Electronics Engineers, Inc. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#) cksum. 1 8.2 (Berkeley) 4/28/95 .\" %FreeBSD: src/usr.bin/cksum/cksum. 1, v 1.10. 2.7 2001/08/16 13:16:43 ru Exp % .\" .\" $FreeBSD: doc/ja_JP.eucJP/man/man1/cksum. 1, v 1.16 2001/09/12 10:44:33 horikawa Exp $ .\" .Dd April 28, 1995 .Dt CKSUM 1 .Os .Sh ¸íĪ .Nm cksum , .Nm sum .Nd ÆÄÀÏÀÇ Ã¼Å© ¼¶°ú ºí·Ï Ä«¿îÆ®¸¦ Ç¥½ÃÇÑ´Ù .Sh ¼­½Ä .Nm .Op Fl o Ar 1 | 2 | 3 .Op Ar .Nm sum .Op Ar .Sh ÇØ¼³ .Nm cksum À¯Æ¿¸®Æ¼´Â, °¢ ÀÔ·Â ÆÄÀÏ¿¡ ´ëÇØ¼­, °ø¹é¿¡¼­ ´Ü¶ôÁö¾îÁø 3 °³ÀÇ Çʵ带 Ç¥ÁØ Ãâ·Â¿¡ Ãâ·ÂÇÕ´Ï´Ù. À̰͵é 3 Çʵå´Â °¢°¢, üũ ¼¶ .Tn CRC , ÆÄÀÏÁßÀÇ 8Áßâ¼ö, ±×¸®°í ÆÄÀϸíÀÔ´Ï´Ù. ÆÄÀÏÀÌ Çϳªµµ ÁöÁ¤µÇÁö ¾Ê´Â °æ¿ì´Â Ç¥ÁØ ÀÔ·ÂÀÌ ÀÌ¿ëµÇ¾î ÆÄÀϸíÀº Ç¥½ÃµÇÁö ¾Ê½À´Ï´Ù. .Pp .Nm sum À¯Æ¿¸®Æ¼´Â .Nm cksum À¯Æ¿¸®Æ¼¿Í °°½À´Ï´Ù¸¸, ÀÌÈÄ¿¡ ÇØ¼³ÇÏ´Â µðÆúÆ®·Î ¿ª»çÀû ¾Ë°í¸®Áò 1 À» »ç¿ëÇÏ´Â Á¡ÀÌ ´Ù¸¨´Ï´Ù. ȣȯ¼º (À») À§Çؼ­¸¸ Á¦°øµÇ°í ÀÖ½À´Ï´Ù. .Pp ¿É¼ÇÀº ÀÌÇÏ¿Í °°½À´Ï´Ù: .Bl -tag -width indent .It Fl o µðÆúÆ®ÀÇ(º¸´Ù ¶Ù¾î³­) ¾Ë°í¸®Áò¿¡ ´ë½ÅÇØ, ¿ª»çÀûÀÎ ¾Ë°í¸®ÁòÀ» ÀÌ¿ëÇÕ´Ï´Ù. .Pp ¾Ë°í¸®Áò 1 Àº .Xr sum 1 ÀÇ ¾Ë°í¸®ÁòÀ¸·Î¼­ ¿ª»çÀûÀÎ .Bx ½Ã½ºÅÛ¿¡ ´ëÇϰí, ¶Ç, .Fl r ¿É¼Ç ÷ºÎ·Î ÀÌ¿ëÇÏ´Â °æ¿ìÀÇ .Xr sum 1 ¾Ë°í¸®ÁòÀ¸·Î¼­ ¿ª»çÀûÀÎ .At V ½Ã½ºÅÛ¿¡ ´ëÇØ ÀÌ¿ëµÇ¾î ¿Â °ÍÀÔ´Ï´Ù. À̰ÍÀº °¡»ê¸¶´Ù ¿À¸¥ÂÊ ·ÎÅ×À̼ÇÀ» ½Ç½ÃÇÏ´Â 16 ºñÆ® üũ ¼¶À̸ç, »êÃâ ³ÑÄ¡°í´Â ¹«½ÃµË´Ï´Ù. .Pp ¾Ë°í¸®Áò 2 ´Â µðÆúÆ®ÀÇ .Xr sum 1 ¾Ë°í¸®ÁòÀ¸·Î¼­ ¿ª»çÀûÀÎ .At V ½Ã½ºÅÛÀ¸·Î ÀÌ¿ëµÇ¾î ¿Â °ÍÀÔ´Ï´Ù. À̰ÍÀº 32 ºñÆ®ÀÇ Ã¼Å© ¼¶À̸ç, ÀÌÇÏ¿Í °°ÀÌ Á¤Àǵ˴ϴÙ: .Bd -unfilled -offset indent s = sum of all bytes; r = s % 2^16 + (s % 2^32) / 2^16; cksum = (r % 2^16) + r / 2^16; .Ed .Pp ¾Ë°í¸®Áò 3 Àº ÀϹÝÀûÀ¸·Î .Ql 32bit CRC ¾Ë°í¸®ÁòÀ¸·Î ºÒ¸®°í ÀÖ´Â °ÍÀÔ´Ï´Ù. À̰ÍÀº 32-bit üũ ¼¶ÀÔ´Ï´Ù. .Pp ¾Ë°í¸®Áò 1, 2 ÀÇ ¸ðµÎ, µðÆúÆ® ¾Ë°í¸®Áò°ú °°Àº Çʵ带 Ç¥ÁØ Ãâ·Â¿¡ ½á³À´Ï´Ù. ´Ù¸¸, ÆÄÀÏ »çÀÌÁî´Â ¹ÙÀÌÆ® ´ÜÀ§´Â ¾Æ´Ï°í ºí·Ï ´ÜÀ§°¡ µË´Ï´Ù. ¿ª»çÀû ÀÌÀ¯·ÎºÎÅÍ, ¾Ë°í¸®Áò 1 ¿¡¼­´Â ºí·Ï »çÀÌÁî´Â 1024, ¾Ë°í¸®Áò 2 ¿¡¼­´Â 512 °¡ µÇ°í ÀÖ½À´Ï´Ù. ºí·Ï¿¡ ¸ø ¹ÌÄ£ ºÎºÐÀº ³¡¸ÎÀ» ¼ö ÀÖ½À´Ï´Ù. .El .Pp µðÆúÆ®·Î ÀÌ¿ëµÈ´Ù .Tn CRC (Àº)´Â, ³×Æ®¿öÅ©ÀÇ Ç¥ÁØ .St -iso8802-3 ¿¡ À־ÀÇ .Tn CRC ¿¡·¯ üũ¿¡ ÀÌ¿ëµÇ´Â ´ÙÇ׽Ŀ¡ ±Ù°ÅÇϰí ÀÖ½À´Ï´Ù. .Tn CRC üũ ¼¶ ÀÎÄÚµùÀº, ´ÙÀ½ÀÇ »ý¼º ´ÙÇ׽Ŀ¡¼­ Á¤Àǵ˴ϴÙ: .Pp .Bd -unfilled -offset indent G(x) = x^32 + x^26 + x^23 + x^22 + x^16 + x^12 + x^11 + x^10 + x^8 + x^7 + x^5 + x^4 + x^2 + x + 1 .Ed .Pp ¼öÇÐÀûÀ¸·Î´Â, ÁÖ¾îÁø ÆÄÀÏ¿¡ ´ëÀÀÇÑ´Ù .Tn CRC °ªÀº ´ÙÀ½ÀÇ ¼ø¼­·Î Á¤Àǵ˴ϴÙ. .Bd -ragged -offset indent Æò°¡µÈ´Ù .Ar n ºñÆ®´Â, 2 ¸¦ ¹ýÀ¸·Î ÇÑ´Ù .Ar n Ns \-1 ´ÙÀ½ ´ÙÇ×½Ä M(x)ÀÇ °è¼ö·Î °£ÁÖÇØÁý´Ï´Ù. ÀÌ·¯ÇÑ .Ar n ºñÆ®´Â ÆÄÀϷκÎÅÍ ¾òÀ» ¼ö ÀÖ½À´Ï´Ù¸¸, ÆÄÀÏÀÇ ÃÖÃÊÀÇ 8ÁßâÀÇ ÃÖ»óÁ¤µµ ºñÆ®¸¦ ÃÖ»óÁ¤µµ, ¸¶Áö¸· 8ÁßâÀÇ ÃÖÇÏÁ¤µµ ºñÆ®¸¦ ÃÖÇÏÁ¤µµ·Î ÇÕ´Ï´Ù. (ÇÊ¿äÇϸé) Á¦·Î ºñÆ®¸¦ ¹¯¾î 8Áßâ´ÜÀ§¿¡ Á¤¸®ÇØ ÆÄÀÏÀÇ ±æÀ̸¦ ¹ÙÀ̳ʸ®Ä¡·Î Ç¥ÇöÇÑ 1 °³ ȤÀº ±× ÀÌ»óÀÇ 8Áßâ(ÃÖÇÏÁ¤µµ 8ÁßâÀÌ ¾Õ)ÀÌ °Å±â¿¡ °è¼ÓµË´Ï´Ù. ÀÌ Á¤¼ö¸¦ Ç¥Çö °¡´ÉÇÑ ÃÖ¼Ò °³¼öÀÇ 8ÁßâÀÌ ÀÌ¿ëµË´Ï´Ù. .Pp M(x)´Â x^32 ¹è(Áï 32 ºñÆ®ÀÇ ¿ÞÂÊ ½¬ÇÁÆ®) ÇØ, 2 ¸¦ ¹ýÀ¸·Î¼­ G(x)·Î ³ª´¯´Ï´Ù. ±× °á°ú 31 Â÷ ÀÌÇÏÀÇ À׿© R(x)¸¦ ¾òÀ» ¼ö ÀÖ½À´Ï´Ù. .Pp R(x)ÀÇ °è¼ö´Â 32 ºñÆ®ÀÇ ºñÆ®¿­À̶ó°í º¸¿©Áý´Ï´Ù. .Pp ±× ºñÆ®¿­À» ¹ÝÀüÇÑ °á°ú°¡ CRC ÀÔ´Ï´Ù. .Ed .Sh Áø´Ü .Ex -std cksum sum .Sh °ü·Ã Ç׸ñ .Xr md5 1 .Pp µðÆúÆ®ÀÇ °è»ê¹æ¹ýÀº, ´ÙÀ½ÀÇ .Tn ACM ³í¹®À¸·Î À¯»ç Äڵ带 ÀÌ¿ëÇØ ±â¼úµÇ°í ÀÖ´Â °Í°ú µî°¡ÀÔ´Ï´Ù. .Rs . %T "Computation of Cyclic Redundancy Checks Via Table Lookup" . %A Dilip V. Sarwate . %J "Communications of the" Tn ACM . %D "August 1988" .Re .Sh Ç¥ÁØ .Nm cksum À¯Æ¿¸®Æ¼´Â .St -p1003.2-92 (À»)¸¦ ¸¸ Çϰí ÀÖ´Ù°í »ý°¢µÇ°í ÀÖ½À´Ï´Ù. .Sh ¿ª»ç .Nm cksum À¯Æ¿¸®Æ¼´Â .Bx 4.4 (À¸)·ÎºÎÅÍ µîÀåÇß½À´Ï´Ù.