CODEWITHSUNDEEP
encryptionopensslbase64aes
Magick.M
Magick.M

Reputation: 655

Decrypting AES encrypted base64 string

so I have a AES-256-ecb base64 string which I decoded using an online tool. However, I'm more of a command line guy so I'm trying to use command line to decode it.

echo "nzE+iKr82Kh8BOQg0k/LViTZJup+9DReAsXd/PCtFZP5FHM7WtJ9Nz1NmqMi9G0i7rGIvhK2jRcGnFyWDT9MLoJvY1gZKI2xsUuS3nJ/n3T1Pe//4kKId+B3wfDW/TgqX6Hg/kUj8JO08wGe9JxtOEJ6XJA3cO/cSna9v3YVf/ssHTbXkb+bFgY7WLdHJyvF6lD/wfpY2ZnA1787ajtm+/aWWVMxDOwKuqIT1ZZ0Nw4=" | openssl enc -aes-256-ecb -d -a -K 366a74cb3c959de17d61db30591c39d1

this is what i've tried but i get bad decrypt error

nzE+iKr82Kh8BOQg0k/LViTZJup+9DReAsXd/PCtFZP5FHM7WtJ9Nz1NmqMi9G0i7rGIvhK2jRcGnFyWDT9MLoJvY1gZKI2xsUuS3nJ/n3T1Pe//4kKId+B3wfDW/TgqX6Hg/kUj8JO08wGe9JxtOEJ6XJA3cO/cSna9v3YVf/ssHTbXkb+bFgY7WLdHJyvF6lD/wfpY2ZnA1787ajtm+/aWWVMxDOwKuqIT1ZZ0Nw4=

is the encrypted base64 text

-aes-256-ecb is the encryption cipher

and 366a74cb3c959de17d61db30591c39d1 is the key

The result is supposed to be another base64 string:

RG9udCB3b3JyeSBzYWtldCBvbmUgZGF5IHdlIHdpbGwgcmVhY2ggdG8Kb3VyIGRlc3RpbmF0aW9uIHZlcnkgc29vbi4gQW5kIGlmIHlvdSBmb3JnZXQgCnlvdXIgdXNlcm5hbWUgdGhlbiB1c2UgeW91ciBvbGQgcGFzc3dvcmQKPT0+ICJ0cmlidXRlX3RvX2lwcHNlYyIKClZpY3Rvciw=

Upvotes: 1

Views: 668

Answers (1)

Joseph Sible-Reinstate Monica
Joseph Sible-Reinstate Monica

Reputation: 48662

What you thought was the hex key was actually the binary key. We know this because if it were the hex representation, then the key would only be 128 bits, but AES-256 needs a key that's 256 bits. The real hex key is effectively a double layer of hex then, so passing 3336366137346362336339353964653137643631646233303539316333396431 as the key instead of 366a74cb3c959de17d61db30591c39d1 makes it work:

$ echo "nzE+iKr82Kh8BOQg0k/LViTZJup+9DReAsXd/PCtFZP5FHM7WtJ9Nz1NmqMi9G0i7rGIvhK2jRcGnFyWDT9MLoJvY1gZKI2xsUuS3nJ/n3T1Pe//4kKId+B3wfDW/TgqX6Hg/kUj8JO08wGe9JxtOEJ6XJA3cO/cSna9v3YVf/ssHTbXkb+bFgY7WLdHJyvF6lD/wfpY2ZnA1787ajtm+/aWWVMxDOwKuqIT1ZZ0Nw4=" | openssl enc -aes-256-ecb -d -a -K 3336366137346362336339353964653137643631646233303539316333396431 | base64
RG9udCB3b3JyeSBzYWtldCBvbmUgZGF5IHdlIHdpbGwgcmVhY2ggdG8Kb3VyIGRlc3RpbmF0aW9u
IHZlcnkgc29vbi4gQW5kIGlmIHlvdSBmb3JnZXQgCnlvdXIgdXNlcm5hbWUgdGhlbiB1c2UgeW91
ciBvbGQgcGFzc3dvcmQKPT0+ICJ0cmlidXRlX3RvX2lwcHNlYyIKClZpY3RvciwPDw8PDw8PDw8P
Dw8PDw8=
$

Upvotes: 1

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