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encryptionopensslhexaes

Encrypt to AES 128 ECB in HEX

I'm trying to use openssl to encrypt plain text into AES 128 ECB in HEX.

Using plain text 11111111111111111111111111111111 and raw key 00000000000000000000000000000000 I'm trying to use:

echo -n "11111111111111111111111111111111" | openssl enc -aes-128-ecb -K 00000000000000000000000000000000 -nosalt | xxd -p

But this gives me:

b6de54f9a78637d1eb523ca7201589f4b6de54f9a78637d1eb523ca72015
89f40143db63ee66b0cdff9f69917680151e

And I'm supposed to get:

FFA3C7ED04710B98067DAE6815E2751F

What am I doing wrong?

Solution

  • You forget to hex decode your plaintext. Furthermore, OpenSSL defaults to PKCS#7 padding, so you should disregard the last block of 16 bytes / 32 hex chars if you need a 16 byte output for a 16 byte input.