online decryption not perform

[Jogi]

 We are having problem in decrypting the AES 128 CTR encrypted key. The key is encrypted using the example project provided in NRF5 SDK16 {aes_ctr}. The following is what is happening

- Raw String "Example string to demonstrate basic usage of AES CTR mode."
- Key "NORDIC SEMICONDUCTORAES&MAC TEST"
- Input iv "0000000000000000"
- Encrypted string Generated by the program : "12DDC3EEDF6E7E04C73BDD0DA3F58E7ECF6DA0A676608A630187A5F6F626B6863A07B3C0FED3E53E9495D505EA62E7234AF89A204C68B22CD6E5"


Then, we are using the encrypted string to be decoded in an online decrypter :
www.cryptogrium.com/aes-ctr.html

- string value as "12DDC3EEDF6E7E04C73BDD0DA3F58E7ECF6DA0A676608A630187A5F6F626B6863A07B3C0FED3E53E9495D505EA62E7234AF89A204C68B22CD6E5"
- Key "NORDIC SEMICONDUCTORAES&MAC TEST"
- OUTPUT : "Invalid Key"

If you notice, the above output is not correct. Can you please let me know why it is not getting decrypted here because I am using the same key and decryption type. What adjustment I need to do to make it work?

[Vidar Berg]

Hello,

The online tool you linked to require all inputs to be represented in binary form so you can't pass the key as text string like you did. Excerpt from the About us page at http://www.cryptogrium.com

"Remember, inputs are binary only (characters 0-9, a-f, or A-F) and two characters represent a byte."

You can use the online converter here to convert your key to a hex string: https://www.rapidtables.com/convert/number/hex-to-ascii.html

[Jogi]

Thanks for the reply. now working .