پروژه رمز نگاری 73353

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شرح پروژه

سلام وقت بخیر شماره شمارو از وب سایت پیدا کردم دو تا پروژه دانشگاهی رمزنگاری داشتم خواستم بدونم قبول زحمت میکنید؟

You sniffed the following Base64 string

ZZJ+BKJNdpXA2jaX8Zg5ItRola18hi95MG8fA/9RPvg=

You know it is an encrypted payload that has been ciphered with these parameters: key = "0123456789ABCDEF" iv = "0123456789ABCDEF" (Note: key and iv are not to be taken as hex strings)

Write a program (based for instance on dec1.c or a modification of enc4.c) to decrypt it and obtain decryptedcontent.

Then, take note of the following instruction in your decryption program if(!EVP_CipherInit(ctx,algorithm_name(), key, iv, ENCRYPT))

When you succeed, build the flag in this way (Python-style string concatenation)

"CRYPTO24{" + decryptedcontent + algorithm_name + "}"

You have found these data

00:9e:ee:82:dc:2c:d4:a0:0c:4f:5a:7b:86:63:b0:c1:ed:06:77:fc:eb:de:1a:23:5d:f4:c3:ff:87:6a:7d:ad:c6:07:fa:a8:35:f6:ae:05:03:57:3e:22:36:76:d5:0d:57:4f:99:f9:58:ad:63:7a:e7:45:a6:aa:fa:02:34:23:b6:9d:34:15:7b:11:41:b6:b1:ca:b9:1a:cd:29:55:bd:42:f5:04:ab:df:45:4a:9d:4e:ca:4e:01:f9:f8:74:59:67:ee:b6:a9:fb:96:b7:c0:94:00:17:8a:53:0e:b6:d8:31:c9:68:e6:64:38:d3:63:3a:04:d7:88:6b:f0:e1:ad:60:7f:41:bd:85:7b:d9:04:e1:97:5b:1f:9b:05:ce:ac:2c:c4:55:3f:b4:8b:89:4d:0a:50:9a:09:4e:5e:8f:5b:5f:55:69:72:5f:04:9b:3a:8a:09:b4:7f:8d:b2:ca:52:0e:5e:bf:f4:b0:ee:c9:ba:dc:93:4f:6d:d3:1f:82:1a:d9:fc:2c:a7:3f:18:23:0d:d7:44:c7:28:54:67:84:ee:73:92:65:f0:1c:e8:1e:6d:4d:95:65:b4:c8:4f:b8:04:62:58:2b:ee:32:64:a0:a7:dc:99:25:0e:50:53:76:bc:30:db:71:5e:93:d6:9f:1f:88:1c:76:5d:82:c8:59:39:51

00:d2:c6:01:32:6b:4c:4b:85:5f:52:7b:b7:8e:d6:8a:e4:c8:76:7e:6b:c9:24:9a:3e:ca:cd:2f:c9:b8:75:d4:f9:71:11:e1:cf:be:62:d3:2c:5f:f9:fd:9b:fa:ed:62:f3:df:44:c7:57:fb:ee:9b:b2:32:cb:54:49:29:6c:69:2e:30:1d:8c:1f:fa:b1:8e:e4:49:66:c1:fb:92:7c:82:ca:60:c9:40:a4:0a:b2:db:50:ec:f6:ff:98:a7:16:23:38:8d:06:d2:7c:a9:85:8a:c2:2b:4d:d4:e6:f1:89:e5:b0:42:54:a0:5f:3c:dd:c7:64:33:05:11:fb:ee:8b:26:07

Find the other missing parameter using BIGNUM primitives (you may have to manipulate these data a bit before).

Use the same representation (with a ':' every two digits). Surround it with CRYPTO24{} to have your flag. Add leading zeros if needed to equalize parameters...

این دو تا سوال دانشگاهی هست که داخل CTF باید جواب رو بزاریم و اگه درست باشه سبز رنگ در میاد

اگه این پروژه براتون مقدور هست ممنون میشم هزینشو اعلام کنید❤️

ترجیحا با سی ولی چون با CTF انجام میشه فقط فلگ واسه من مهمه که جواب درستو وارد کنم تو پرتال

زمان هم تا فردا متاسفانه

مهارت ها و تخصص های مورد نیاز

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