201108042016 j95o6
best-guess decrypted manual
A quotation framed in ASCII art that spells USA. 3DES, key MD5(name). Best guess: the 32-byte hex tail is two masked GUIDs (filler); the seed is not identified.
From the post to its content
As posted (encrypted)
64C6BF1DAD DE78254B34 D26306D7C6 6E35F53545 C3650E12DB 84E9E943F8 A815EFF9AC 61E990989F 4743648D21 BEB61EAC82 45F6E07E8C 0BA8C209DB EB442D0560 72740D3E7D 5138217E2E 80AFD30C2A 0689D292A9 E567F40445 6D3950428C D14D019266 8CD43B7028 AD2125D2CF 74AD2B673B F99816C6E4 79FD7288EC 6DBC54595A 2B894F85D0 0F977FF960 A7A37BB44E BF7D73824A 92ED53A2E9 ED90239F80 C3EDB78839 E0F853D95B C52FD51388 FF217E2E80 AFD30C2A5B BCB3D70464 E6C19C699F 9F45358EB9 21E3AB8CF5 15CEBDA463 535D6C634F 6F94CF215F AD7C6C476C 87BF66FF95 4264DF8010 BB1C238F2E 9FAF62E417 C6BA90C4CA 7CA56A8D21 C7CDFF730D FE377D8954 3A4DC84F00 C90FCC079D A9AC3B5400 28E9DCA6BE EC2A5F0E44 7001BB14A7 CA0ABC9098 AFD8D357F5 6FD61B0F96 A233CCCD52 EE04BCAD25 865F2BD731 4A5229C3CC EB03E3B5C0 71D74299EE B6B16C3CA7 DDCA6F1C91 2148CEDD99 423560B21B 5795343C13 354D54AAAC EAE809F23B DCA3ECF9F3 D4F6253F10 FC6BFBD5BA 417C1FE543 9BD2A057DA AC5DE7D044 D76A740345 ED7FE1D206 6B8F152B7E C85A1BCED1 138C22088C 333F13BC6D 49E8D918EB CE84D870F7 F595AADFC0 E8FA68E2B1 2CC2DF9808 14CF14531D 2A451C7CE9 0FFAF1BF2D A927A4307F 639BB36D3D 2CA7D4DE94 FE9A8FBC75 A997ED600F BF8A1F6263 F787FADFB2 207F8F68BB DE8D252BE2 A5AC985F7B 78D5D01E68 723EAB934F FCB4BE9692 F63524A434 A39DE050B5 7B06A14815 EA42EC46BB 2D12D299B0 B8A9B39D4F D38A92618D E7B70E21DD 8E1F631765 CED6B2FCEC E989E1DBFA 1A15889059
- Decrypt. Key: MD5(name) ECB. 3DES-EDE2, then strip the PKCS7 padding.
Decrypted
. | / \ "Since, in the long run, every planetary | | civilization will be endangered by impacts | U | from space, every surviving civilization | | is obliged to become spacefaring--not | S | because of exploratory or romantic zeal, | | but for the most practical reason | A | imaginable: staying alive... If our | | long-term survival is at stake, we have |___| a basic responsibility to our species H H to venture to other worlds." /v\ /v\ V V f83fbd3b 57667e87 981db071 6ea91900 6d60c781 63784024 82447a34 19c7b0af
Explanation
201108042016 — DES-EDE ECB quotation
Status: verified decryption; the trailing 32 bytes are a best guess.
This is one of six 2011 posts that use the same recipe (the others: igg5w, j7525, j7xpy, jb62l, jbnny):
- Decode the body from hexadecimal.
- Use DES-EDE (two-key Triple DES) in ECB mode with the 16-byte key MD5(
A858DE45F56D9BC9). - Remove the PKCS#7 padding.
The SHA-256 of the plaintext, for checking a decryption byte for byte:
4d4a314bd088772cf0bc99e1ff567aaa981e454e3c6b73d9972cc00475db21e4
The output contains a spacefaring-survival quotation, ASCII art spelling USA, and this trailing hex-looking material:
f83fbd3b 57667e87 981db071 6ea91900
6d60c781 63784024 82447a34 19c7b0af
The quotation and the art are solved. The trailing 32-byte value is a best guess. Its two 16-byte lines have the shape of masked GUIDs: each has a version digit from 0 to 8, the range the mask-digit generator produces, and a variant digit from 8 to B, as a GUID has. That shape is about 50 times more likely than for random bytes. But no seed from 0 to 999 reproduces the version digits more often than chance, so the seed that made the lines is not identified. The tail did not decode, decrypt or match any hash or key that was tested, which is why this post is marked best guess rather than solved.
Solution summary
- Method
- 3DES-ECB, key MD5(name)
- Result
- ASCII-framed quotation, then a 32-byte hex tail
- Explanation
- Quotation decrypted; the tail is a best guess that it is two masked GUIDs (filler): version nibbles 7 and 4 fit Random(seed).Next(9) (12 of 1,000 seeds at offset 0, chance), variant bits 9 and 8, seed not identified; no hash or key found