201208031720 xn1xq

explained decrypted filler

seed 75

Metadata

Post ID: xn1xq
Title: 201208031720 → 2012-08-03 17:20 on A858's clock
Posted (UTC): 2012-08-03 21:17:41
Timezone: UTC−4 · title 17:20 against posted 21:17 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 2,192 hex characters · 1,096 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9A858DE45F56D9BC9) = 0dcc4bd9e114ebc42078977dc9125404 (name+name)
GUIDs: 34
Filler GUID seed: new Random(75).Next(9) ✓ verified
Run: Run 22 (seed 528,385,484) (seed)
Draw: 9 · predicted N = 34 ✓
Machine boot: 2012-07-27 19:02–19:13 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 8 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listkey: name+namerun: seed

From the post to its content

As posted (encrypted)

3A1E55F5CCC1D968 DB8A2736856CA444 6FF91C947D69A4DB 7F1892B85F8DEB4B 5399E13206FE7E86 CC2A4E1ABEBC7DF5 95ED4BB5F996B140 4CB36125266FA8BE 8A9439B849EC9AD1 47137D968DE4B7B3 2890E6268DA59D68 A4467A25885253D4 E5BB7EBDAC87754B 2BD6376BDC2321DC 408A81462C4195B0 389E72C98406D10E CBC8905640BD2820 DA5E2731B195E48D A47DF41E672A29FC AD7D20F857D60607 6D71D46BF75FF1C3 FC80BB40AE4B3E12 266A14773B46B46A C16F5CBF56B56934 84E335F839D69BC5 83E510670739F3F4 61593E6C70CB081C FD07DDF459F248D1 4C9E66CACB564628 C8FB5C106DDC244D 2040C3B4CED3EA7B 26E8D3D2F08E2124 7738941A77303602 EEA671B0EE492EF9 CAD5A4E194C7E47E 29E7B57A9E418CD3 7520B9E42A6B29AA 6163200127C2445D 85052C76DEEDF40F 554EF41F6AD28BA7 DD35A278DB683DA7 614DC7DC65D47359 31E5E057584E8B12 83F24B0C0A8087A0 CCFA01B8E0470700 A93DB39610DA7CC1 0204437E177F989F 765D9D823334AC8C E777086A35AC922F B6FF52EC5E1E2AB5 A735B8AAF54F3CD3 37F3D4AFB4B28D9F 8974A78A1E1B0BC5 F40D794C9C2D9E5C 0C8644C97282D702 94AA9148D6D7F1C1 8D98E1504D654AB7 C8814DB4ED7988A5 8070CB94DD96FD72 28A55DCDF3611C53 5FF55B8D791A8E0C 9117D7AA19F3E9A0 91FB92FA6BE21358 0BF6CF05B60E24CB 616990EC3B2CEBFE C46A7C371F0826DE 076FCBF90E7DA2F8 8D2FBC3400AD2239 E65268CE88E0DB25 447D7B58F0FE8672 56F7268075352F04 90F7015181C9C996 8D3E28D7C271A16B 289967ABFD776CEC 1E3ED0564CC69CD5 1EA2B1951523619F 63622C31305DAF8E EA27A4C772306891 EB9E801DE3F81064 815310173F60FEC3 BD9AC092D209E58A 67570BB524AF74D2 4A6BEA84F6C497CB B2DDBF28F709083A 8ED9EFB4A9C58B6C 40EA4A8FB11CDB7F 3E5E890BC042B110 E0EAD15BD7006506 18D2CA7DD4BEB06F A6B9E56B3C78E33C 7C542926E33B413C 9AD5303A274CD9A4 13F824313C670829 939CD1972E491870 4053BE81F95E40C2 6166A1B530ED0393 84B13AB4E0958FF0 2B6EEAA45C82DBE4 9D12FD20E3EF473B DAA635536CB5CD61 CCB13BF7CABC414C 4BE9046153ED332B B1B4A8ABEBEEE45E 918DCBA6FC41DB1A 4E5AF3C98597F7AA 4F05D1A7833554D3 4EEA694601CAE547 1434453A840BDA61 0A42B31AEF30BCE1 C451814974E36973 E3AAFA68096D75A8 2B570E2E5D11C996 C8E6763D00E944B5 8C50805D6A6EEC2B 084A536F77923DC7 F859958EE358BB5B 2F0EBB59A14E3BD1 EDE291AC6E751975 FCD1C2D8DDB95FCE A6D113F2FC192904 64A79AC912F44ACC F4C810D6539AACF7 A4AF329898E75225 8E192502F1C27189 C7618E21CAFAFF94 6C0E80B700182E1C 1AADE02D348BDECA 28D799FC40ADCEB0 F66B850EE395867C B89B274AABAD8F27 447420FCBDA34EF7 E51343A7DC7234C9 76E84CB78B74392D 29139D6D991D9E7F 9C0E058DF9B2949D 0E9992C4C05868D7 12ECFFDF2899BD4C

Read the ciphertext. Strip whitespace: 2,192 hex characters = 1,096 bytes = 137 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9A858DE45F56D9BC9 (name+name). Key = MD5(password) = 0dcc4bd9e114ebc42078977dc9125404, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 34 GUIDs as hex (shown below).

Decrypted: GUID list

  1 35fe31ad-42a8-85fb-b7a2-7957f040aa37
  2 22689c18-b663-7b6a-9f7f-13349593a700
  3 825add39-4e14-1843-9b0f-cb2ca4664918
  4 5f13d4e7-afa4-5327-9cc7-212a24dc7419
  5 9853f6c4-c6e6-096c-8b70-d7afa72dca55
  6 275cf800-0cd5-0fff-9892-205f200514dc
  7 6510937f-6e09-469e-ac73-7641af491aa7
  8 3eb055b6-628c-0c20-95f6-d864b1939b33
  9 0cc949fd-ff84-2ac5-a1e0-055c450711fd
 10 27278b38-feb5-812b-a933-80980239d8fb
 11 9d08c4d2-ac27-4efe-b7ae-a0370a930fdc
 12 4fb936e4-fe5a-0f45-b83e-bfa6a31e0b51
 13 93fb5c35-c28e-131d-ae2e-58af4b61b51b
 14 b0ae0231-98f5-49d3-91fa-e6e03bb5e363
 15 a8764bcd-f3c5-4b1b-b178-48c037205f41
 16 a95a52be-76ef-76f9-902a-fd16ea3e7897
 17 3967a990-94da-36f6-a2e4-b31e7344b616
 18 093ad8bb-2b90-4bc9-8605-db9a26a462fd
 19 db7e0aef-21db-685f-a660-d91628db6d95
 20 ae86cfb2-e76b-34d7-b42c-319fcb5def90
 21 1ce1fd1a-d670-738a-8602-82316437f907
 22 a6a436de-aef6-2bb2-9987-beb072442d0e
 23 a729f15a-b746-6718-82ba-1be7f2ccc431
 24 a005d5c0-ec61-2d5e-a94e-3fc738f13053
 25 12464ad7-d291-0060-bd8f-818115bd80ee
 26 55377a90-e590-6044-be3b-428f859bd4a8
 27 1bf138ed-c4cd-3ccf-9aae-cee0faa4fabc
 28 32e90131-deb1-1b5c-a6cc-82bf7c7f097b
 29 5b44ec5c-1b81-2166-b04c-d177283a1719
 30 ff871ae6-376d-4d2e-bd6f-4e224ecde38d
 31 0e71b283-dbbd-7363-8301-83e0c0ecbc40
 32 20944ff8-04a5-11f7-b670-773fdfbba3f1
 33 9b65e1d3-9b43-4361-b936-7d7b5c221143
 34 ee0b604b-ad66-7cd0-a48d-9792bd8e7164

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 8715004028401447346372620631247147. Exactly this sequence comes out of new Random(75).Next(9): the per-post millisecond seed of the mask generator. The other 30 hex digits of each GUID are Guid.NewGuid() output and carry no message.
Explain the count. This post is draw 9 of Run 22 (seed 528,385,484): new Random(528385484), Next(8,64) per post. The RNG predicts N = 34; the post has N = 34 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-07-27 19:02–19:13).
Conclusion. Filler. The content is fully explained by the two RNGs.

Metadata

From the post to its content

As posted (encrypted)

Decrypted: GUID list

Explanation

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