Securinets CTF Quals 2019 Writeup Misc EZ

EZ

Welcome to Securinets, this one is an easy one.

Please make sure you hash the WORD with sha1 (lowercase hash letter)

The final flag is : Securinets{the_hash_of_the_word}

与えられたzipを解凍すると↓の画像が出てくる。

pic.png f:id:Yunolay:20190325093711p:plain

strings, steghide, foremostとかしたけど気になることは特にない。 stegsolveとかカチカチしてたらRGB LSB0ビットを抽出したときに文字列が出てきた。

f:id:Yunolay:20190325094326p:plain

--START--
"The fact is that upon his entrance I had instantly recognized the extreme
personal danger in which I lay. The only conceivable escape for him lay in silencing
my tongue. In an instant I had slipped the revolver from the drawer into my
pocket and was covering him through the cloth. At his remark I drew the weapon
out and laid it cocked upon the table. He still smiled and blinked, but there was
something about his eyes which made me feel very glad that I had it there,
"You evidently don't know me,' said he.
"'On the contrary,' I answered, 'I think it is fairly evident that I do. Pray take
a chair. I can spare you five minutes if you have anything to say.'
"'All that I have to say has already crossed your mind,' said he.
"'Then possibly my answer has crossed yours,' I replied.
"'You stand fast?'
"'Absolutely.'
"He clapped his hand into his pocket, and I raised the pistol from the table.
But he merely drew out a <DETELED_WORD> in which he had scribbled some
dates.
"You crossed my path on the fourth of January,' said he. 'On the twenty-third
you incommoded me; by the middle of February I was seriously inconvenienced
by you; at the end of March I was absolutely hampered in my plans; and now, at
the close of April, I find myself placed in such a position through your continual
persecution that I am in positive danger of losing my liberty. The situation is
becoming an impossible one.'
"'Have you any suggestion to make?' I asked.
"'You must drop it, Mr. Holmes,' said he, swaying his face about. 'You really
must, you know.'"
--END--

英語が分からないのでWhat's thisって感じ。Google翻訳に頼る癖がいけない。 とりあえず縦読みとか会話の先頭だけとかをRotとかしてみたけど特に何もない。 大変困っていたところ<DETELED_WORD>が目に入った。

"He clapped his hand into his pocket, and I raised the pistol from the table. ぐぐった

www.pagebypagebooks.com

"He clapped his hand into his pocket, and I raised the pistol from the table. But he merely drew out a memorandum-book in which he had scribbled some dates.

memorandum-bookがわかったのでsha1でハッシュする。

FLAG : Securinets{b47f0d2a8866a75696f94a515d0cdf54c7ea3174}