/*ððððð*ððcss_descramble.cððððð*ððððð*ððReleasedðunderðtheðversionð2ðofðtheðGPL.ððððð*ððððð*ððCopyrightð1999ðDerekðFawcusððððð*ððððð*ððThisðfileðcontainsðfunctionsðtoðdescrambleðCSSðencryptedðDVDðconten
tððððð*ððððð*/ðððððððð/*ððððð*ððStillðinðprogress:ððRemoveðtheðuseðofðtheðbit_reverse[]ðtableðbyðrecodingððððð*ððððððððððððððððððððððtheðgenerationðofðLFSR1.ððFinishðcombiningðthisðwithððððð*ððððððððððð
ðððððððððððtheðcssðauthenticationðcode.ððððð*ððððð*/ðððððððð#includeð(stdio.h)ðððð#includeð(string.h)ðððð#includeð"css-descramble.h"ððððððððtypedefðunsignedðcharðbyte;ðððððððð/*ððððð*ððððð*ððsomeðtables
ðusedðforðdescramblingðsectorsðand/orðdecryptingðtitleðkeysððððð*ððððð*/ððððððððstaticðbyteðcsstab1[256]=ðððð{ððððð0x33,0x73,0x3b,0x26,0x63,0x23,0x6b,0x76,0x3e,0x7e,0x36,0x2b,0x6e,0x2e,0x66,0x7b,ððððð0x
d3,0x93,0xdb,0x06,0x43,0x03,0x4b,0x96,0xde,0x9e,0xd6,0x0b,0x4e,0x0e,0x46,0x9b,ððððð0x57,0x17,0x5f,0x82,0xc7,0x87,0xcf,0x12,0x5a,0x1a,0x52,0x8f,0xca,0x8a,0xc2,0x1f,ððððð0xd9,0x99,0xd1,0x00,0x49,0x09,0x41
,0x90,0xd8,0x98,0xd0,0x01,0x48,0x08,0x40,0x91,ððððð0x3d,0x7d,0x35,0x24,0x6d,0x2d,0x65,0x74,0x3c,0x7c,0x34,0x25,0x6c,0x2c,0x64,0x75,ððððð0xdd,0x9d,0xd5,0x04,0x4d,0x0d,0x45,0x94,0xdc,0x9c,0xd4,0x05,0x4c,0
x0c,0x44,0x95,ððððð0x59,0x19,0x51,0x80,0xc9,0x89,0xc1,0x10,0x58,0x18,0x50,0x81,0xc8,0x88,0xc0,0x11,ððððð0xd7,0x97,0xdf,0x02,0x47,0x07,0x4f,0x92,0xda,0x9a,0xd2,0x0f,0x4a,0x0a,0x42,0x9f,ððððð0x53,0x13,0x5
b,0x86,0xc3,0x83,0xcb,0x16,0x5e,0x1e,0x56,0x8b,0xce,0x8e,0xc6,0x1b,ððððð0xb3,0xf3,0xbb,0xa6,0xe3,0xa3,0xeb,0xf6,0xbe,0xfe,0xb6,0xab,0xee,0xae,0xe6,0xfb,ððððð0x37,0x77,0x3f,0x22,0x67,0x27,0x6f,0x72,0x3a,
0x7a,0x32,0x2f,0x6a,0x2a,0x62,0x7f,ððððð0xb9,0xf9,0xb1,0xa0,0xe9,0xa9,0xe1,0xf0,0xb8,0xf8,0xb0,0xa1,0xe8,0xa8,0xe0,0xf1,ððððð0x5d,0x1d,0x55,0x84,0xcd,0x8d,0xc5,0x14,0x5c,0x1c,0x54,0x85,0xcc,0x8c,0xc4,0x
15,ððððð0xbd,0xfd,0xb5,0xa4,0xed,0xad,0xe5,0xf4,0xbc,0xfc,0xb4,0xa5,0xec,0xac,0xe4,0xf5,ððððð0x39,0x79,0x31,0x20,0x69,0x29,0x61,0x70,0x38,0x78,0x30,0x21,0x68,0x28,0x60,0x71,ððððð0xb7,0xf7,0xbf,0xa2,0xe7
,0xa7,0xef,0xf2,0xba,0xfa,0xb2,0xaf,0xea,0xaa,0xe2,0xffðððð};ððððððððstaticðbyteðlfsr1_bits0[256]=ðððð{ððððð0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x09,0x08,0x0b,0x0a,0x0d,0x0c,0x0f,0x0e,ððððð0x12,0x13
,0x10,0x11,0x16,0x17,0x14,0x15,0x1b,0x1a,0x19,0x18,0x1f,0x1e,0x1d,0x1c,ððððð0x24,0x25,0x26,0x27,0x20,0x21,0x22,0x23,0x2d,0x2c,0x2f,0x2e,0x29,0x28,0x2b,0x2a,ððððð0x36,0x37,0x34,0x35,0x32,0x33,0x30,0x31,0
x3f,0x3e,0x3d,0x3c,0x3b,0x3a,0x39,0x38,ððððð0x49,0x48,0x4b,0x4a,0x4d,0x4c,0x4f,0x4e,0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47,ððððð0x5b,0x5a,0x59,0x58,0x5f,0x5e,0x5d,0x5c,0x52,0x53,0x50,0x51,0x56,0x57,0x5
4,0x55,ððððð0x6d,0x6c,0x6f,0x6e,0x69,0x68,0x6b,0x6a,0x64,0x65,0x66,0x67,0x60,0x61,0x62,0x63,ððððð0x7f,0x7e,0x7d,0x7c,0x7b,0x7a,0x79,0x78,0x76,0x77,0x74,0x75,0x72,0x73,0x70,0x71,ððððð0x92,0x93,0x90,0x91,
0x96,0x97,0x94,0x95,0x9b,0x9a,0x99,0x98,0x9f,0x9e,0x9d,0x9c,ððððð0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87,0x89,0x88,0x8b,0x8a,0x8d,0x8c,0x8f,0x8e,ððððð0xb6,0xb7,0xb4,0xb5,0xb2,0xb3,0xb0,0xb1,0xbf,0xbe,0x
bd,0xbc,0xbb,0xba,0xb9,0xb8,ððððð0xa4,0xa5,0xa6,0xa7,0xa0,0xa1,0xa2,0xa3,0xad,0xac,0xaf,0xae,0xa9,0xa8,0xab,0xaa,ððððð0xdb,0xda,0xd9,0xd8,0xdf,0xde,0xdd,0xdc,0xd2,0xd3,0xd0,0xd1,0xd6,0xd7,0xd4,0xd5,ðððð
ð0xc9,0xc8,0xcb,0xca,0xcd,0xcc,0xcf,0xce,0xc0,0xc1,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7,ððððð0xff,0xfe,0xfd,0xfc,0xfb,0xfa,0xf9,0xf8,0xf6,0xf7,0xf4,0xf5,0xf2,0xf3,0xf0,0xf1,ððððð0xed,0xec,0xef,0xee,0xe9,0xe8,0
xeb,0xea,0xe4,0xe5,0xe6,0xe7,0xe0,0xe1,0xe2,0xe3ðððð};ððððððððstaticðbyteðlfsr1_bits1[512]=ðððð{ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0
x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x2
4,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0x
b6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d
,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0
x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xf
f,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,
0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x
6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24
,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ð
ðððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb
6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,
0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,ððððð0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xffðððð};ððððððð
ð/*ðReverseðtheðorderðofðtheðbitsðwithinðaðbyte.ððððð*/ððððstaticðbyteðbit_reverse[256]=ðððð{ððððð0x00,0x80,0x40,0xc0,0x20,0xa0,0x60,0xe0,0x10,0x90,0x50,0xd0,0x30,0xb0,0x70,0xf0,ððððð0x08,0x88,0x48,0xc8
,0x28,0xa8,0x68,0xe8,0x18,0x98,0x58,0xd8,0x38,0xb8,0x78,0xf8,ððððð0x04,0x84,0x44,0xc4,0x24,0xa4,0x64,0xe4,0x14,0x94,0x54,0xd4,0x34,0xb4,0x74,0xf4,ððððð0x0c,0x8c,0x4c,0xcc,0x2c,0xac,0x6c,0xec,0x1c,0x9c,0
x5c,0xdc,0x3c,0xbc,0x7c,0xfc,ððððð0x02,0x82,0x42,0xc2,0x22,0xa2,0x62,0xe2,0x12,0x92,0x52,0xd2,0x32,0xb2,0x72,0xf2,ððððð0x0a,0x8a,0x4a,0xca,0x2a,0xaa,0x6a,0xea,0x1a,0x9a,0x5a,0xda,0x3a,0xba,0x7a,0xfa,ððð
ðð0x06,0x86,0x46,0xc6,0x26,0xa6,0x66,0xe6,0x16,0x96,0x56,0xd6,0x36,0xb6,0x76,0xf6,ððððð0x0e,0x8e,0x4e,0xce,0x2e,0xae,0x6e,0xee,0x1e,0x9e,0x5e,0xde,0x3e,0xbe,0x7e,0xfe,ððððð0x01,0x81,0x41,0xc1,0x21,0xa1,
0x61,0xe1,0x11,0x91,0x51,0xd1,0x31,0xb1,0x71,0xf1,ððððð0x09,0x89,0x49,0xc9,0x29,0xa9,0x69,0xe9,0x19,0x99,0x59,0xd9,0x39,0xb9,0x79,0xf9,ððððð0x05,0x85,0x45,0xc5,0x25,0xa5,0x65,0xe5,0x15,0x95,0x55,0xd5,0x
35,0xb5,0x75,0xf5,ððððð0x0d,0x8d,0x4d,0xcd,0x2d,0xad,0x6d,0xed,0x1d,0x9d,0x5d,0xdd,0x3d,0xbd,0x7d,0xfd,ððððð0x03,0x83,0x43,0xc3,0x23,0xa3,0x63,0xe3,0x13,0x93,0x53,0xd3,0x33,0xb3,0x73,0xf3,ððððð0x0b,0x8b
,0x4b,0xcb,0x2b,0xab,0x6b,0xeb,0x1b,0x9b,0x5b,0xdb,0x3b,0xbb,0x7b,0xfb,ððððð0x07,0x87,0x47,0xc7,0x27,0xa7,0x67,0xe7,0x17,0x97,0x57,0xd7,0x37,0xb7,0x77,0xf7,ððððð0x0f,0x8f,0x4f,0xcf,0x2f,0xaf,0x6f,0xef,0
x1f,0x9f,0x5f,0xdf,0x3f,0xbf,0x7f,0xffðððð};ðððððððð/*ððððð*ððððð*ðthisðfunctionðisðonlyðusedðinternallyðwhenðdecryptingðtitleðkeyððððð*ððððð*/ððððstaticðvoidðcss_titlekey(byteð*key,ðbyteð*im,ðbyteðinve
rt)ðððð{ðððððunsignedðintðlfsr1_lo,lfsr1_hi,lfsr0,combined;ðððððbyteðo_lfsr0,ðo_lfsr1;ðððððbyteðk[5];ðððððintði;ðððððððððlfsr1_loð=ðim[0]ð|ð0x100;ðððððlfsr1_hið=ðim[1];ðððððððððlfsr0ð=ð((im[4]ð((ð17)ð|ð
(im[3]ð((ð9)ð|ð(im[2]ð((ð1))ð+ð8ð-ð(im[2]&7);ðððððlfsr0ð=ð(bit_reverse[lfsr0&0xff]((24)ð|ð(bit_reverse[(lfsr0))8)&0xff]ð((ð16)ðððððððð|ð(bit_reverse[(lfsr0))16)&0xff]((8)ð|ðbit_reverse[(lfsr0))24)&0xff]
;ðððððððððcombinedð=ð0;ðððððforð(ið=ð0;ðið(ð5;ð++i)ð{ððððððo_lfsr1ðð=ðlfsr1_bits0[lfsr1_hi]ð^ðlfsr1_bits1[lfsr1_lo];ððððððððlfsr1_hið=ðlfsr1_lo))1;ððððððððlfsr1_loð=ð((lfsr1_lo&1)((8)ð^ðo_lfsr1;ððððððo_
lfsr1ðð=ðbit_reverse[o_lfsr1];ðððððððððð/*o_lfsr0ð=ð(lfsr0))7)^(lfsr0))10)^(lfsr0))11)^(lfsr0))19);*/ððððððo_lfsr0ð=ð(((((((lfsr0))8)^lfsr0)))1)^lfsr0)))3)^lfsr0)))7);ððððððððlfsr0ð=ð(lfsr0))8)|(o_lfsr0
((24);ððððððððððcombinedð+=ð(o_lfsr0ð^ðinvert)ð+ðo_lfsr1;ððððððk[i]ð=ðcombinedð&ð0xff;ððððððcombinedð))=ð8;ððððð}ðððððððððkey[4]=k[4]^csstab1[key[4]]^key[3];ðððððkey[3]=k[3]^csstab1[key[3]]^key[2];ððððð
key[2]=k[2]^csstab1[key[2]]^key[1];ðððððkey[1]=k[1]^csstab1[key[1]]^key[0];ðððððkey[0]=k[0]^csstab1[key[0]]^key[4];ðððððððððkey[4]=k[4]^csstab1[key[4]]^key[3];ðððððkey[3]=k[3]^csstab1[key[3]]^key[2];ððð
ððkey[2]=k[2]^csstab1[key[2]]^key[1];ðððððkey[1]=k[1]^csstab1[key[1]]^key[0];ðððððkey[0]=k[0]^csstab1[key[0]];ðððð}ðððððððð/*ððððð*ððððð*ðthisðfunctionðdecryptsðaðtitleðkeyðwithðtheðspecifiedðdiskðkeyðð
ððð*ððððð*ðtkey:ðtheðunobfuscatedðtitleðkeyð(XORedðwithðBusKey)ððððð*ðdkey:ðtheðunobfuscatedðdiskðkeyð(XORedðwithðBusKey)ððððð*ððððððð2048ðbytesðinðlengthð(thoughðonlyð5ðbytesðareðneeded,ðseeðbelow)ðððð
ð*ðpkey:ðarrayðofðpointersðtoðplayerðkeysðandðdiskðkeyðoffsetsððððð*ððððð*ððððð*ðuseðtheðresultðreturnedðinðtkeyðwithðcss_descrambleððððð*ððððð*/ððððððððintðcss_decrypttitlekey(byteð*tkey,ðbyteð*dkey,ðs
tructðplaykeyð**pkey)ðððð{ðððððbyteðtest[5],ðpretkey[5];ðððððintðið=ð0;ðððððððððforð(;ð*pkey;ð++pkey,ð++i)ð{ððððððmemcpy(pretkey,ðdkeyð+ð(*pkey)-)offset,ð5);ððððððcss_titlekey(pretkey,ð(*pkey)-)key,ð0);
ððððððððððmemcpy(test,ðdkey,ð5);ððððððcss_titlekey(test,ðpretkey,ð0);ððððððððððifð(memcmp(test,ðpretkey,ð5)ð==ð0)ð{ðððððððfprintf(stderr,ð"UsingðKeyð%d\n",ði+1);ðððððððbreak;ðððððð}ððððð}ðððððððððifð(!*
pkey)ð{ððððððfprintf(stderr,ð"Shitð-ðNeedðKeyð%d\n",ði+1);ððððððreturnð0;ððððð}ðððððððððcss_titlekey(tkey,ðpretkey,ð0xff);ðððððððððreturnð1;ðððð}ðððððððð/*ððððð*ððððð*ðthisðfunctionðdoesðtheðactualðdesc
ramblingððððð*ððððð*ðsec:ðencryptedðsectorð(2048ðbytes)ððððð*ðkey:ðdecryptedðtitleðkeyðobtainedðfromðcss_decrypttitlekeyððððð*ððððð*/ððððvoidðcss_descramble(byteð*sec,byteð*key)ðððð{ðððððunsignedðintðlf
sr1_lo,lfsr1_hi,lfsr0,combined;ðððððunsignedðcharðo_lfsr0,ðo_lfsr1;ðððððunsignedðcharð*endð=ðsecð+ð0x800;ðððð#defineðSALTED(i)ð(key[i]ð^ðsec[0x54ð+ð(i)])ðððððððððlfsr1_loð=ðSALTED(0)ð|ð0x100;ðððððlfsr1_
hið=ðSALTED(1);ðððððððððlfsr0ð=ð((SALTED(4)ð((ð17)ð|ð(SALTED(3)ð((ð9)ð|ð(SALTED(2)ð((ð1))ð+ð8ð-ð(SALTED(2)&7);ðððððlfsr0ð=ð(bit_reverse[lfsr0&0xff]((24)ð|ð(bit_reverse[(lfsr0))8)&0xff]ð((ð16)ðððððððð|ð(
bit_reverse[(lfsr0))16)&0xff]((8)ð|ðbit_reverse[(lfsr0))24)&0xff];ðððððððððsec+=0x80;ðððððcombinedð=ð0;ðððððwhileð(secð!=ðend)ð{ððððððo_lfsr1ðð=ðlfsr1_bits0[lfsr1_hi]ð^ðlfsr1_bits1[lfsr1_lo];ððððððððlfs
r1_hið=ðlfsr1_lo))1;ððððððððlfsr1_loð=ð((lfsr1_lo&1)((8)ð^ðo_lfsr1;ððððððo_lfsr1ðð=ðbit_reverse[o_lfsr1];ðððððððððð/*o_lfsr0ð=ð(lfsr0))7)^(lfsr0))10)^(lfsr0))11)^(lfsr0))19);*/ððððððo_lfsr0ð=ð(((((((lfs
r0))8)^lfsr0)))1)^lfsr0)))3)^lfsr0)))7);ððððððððlfsr0ð=ð(lfsr0))8)|(o_lfsr0((24);ððððððððððcombinedð+=ðo_lfsr0ð+ð(byte)~o_lfsr1;ðððððð*sec++ð=ðcsstab1[*sec]ð^ð(combined&0xff);ððððððcombinedð))=ð8;ððððð}
ðððð}/*ð###############################################################################################################################################################################################ð*/
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DVD Copying and Encryption
Ilya Beylin
Larry Estrada
Seth Hallem
Tyron Stading
Steven Stegman
For Eric Roberts, CS201
Stanford University
History
The DVD encryption was initially hacked by a group of Norwegian hackers, CORE,
who released their decryption program, called DeCSS, onto the Internet.
DeCSS was the first program to break one of the universal DVD keys, allowing
the program to play DVDs that were encoded for any geographic region. The
hackers reverse-engineered XingDVD,
Realnetworks' DVD player, to get their algorithm.
The Motion Picture Association of America (MPAA) responded by sending
"cease and desist" letters to website operators who posted DeCSS,
also bringing Êlawsuits against specific
webmasters. The Electronic Frontier Foundation (EFF) came to the defense
of these website operators by providing free legal defense. The EFF
claimed that preventing the operators from posting the code was an illegal
censorship of free speech and that the algorithm was valuable for scientific
and educational purposes. The MPAA claimed that providing access to DeCSS
was a violation of the Digital Millennium copyright Act.
The judge ruled in favor of the MPAA, setting a precedent whereby ISPs could potentially be liable for material posted on home pages they give to their users unless they can prove they did not know that their users had posted that material (this is a more stringent argument than merely Common Carrier). Other lawsuits have been filed by the DVD Copy Control Association against website operators (under appeal after plaintiffâs success).
Analysis
We think that rulings in favor of the plaintiffs would, in our opinion, set a dangerous precedent of potential suppression of controversial information. The contents of DVDs are clearly protected by copyrights. The algorithm is a mathematical formula, and therefore, it cannot be copyrighted÷it must be held as a trade secret. Fair Use must also be supported as well, if for no reason other than to protect the rights of researchers and academics.