Intro to Application-level Security Using the ECB Peripheral

RE: Intro to Application-level Security Using the ECB Peripheral

Embedded_Engineer — Thu, 19 Mar 2020 14:07:35 GMT

is this supported on nrf52840, as in the product specification it mentions section 6.7 ECB-AES " (encryption only, not decryption)"

RE: Intro to Application-level Security Using the ECB Peripheral

Abhishek Chauhan — Fri, 27 Apr 2018 07:13:19 GMT

nrf_delay_us(RNG_BYTE_WAIT_US * remaining); Does delay depend on the no of remaining bytes. If yes then how..

RE: Intro to Application-level Security Using the ECB Peripheral

Abhishek Chauhan — Fri, 27 Apr 2018 07:11:55 GMT

nrf_delay_us(RNG_BYTE_WAIT_US * remaining);

RE: Intro to Application-level Security Using the ECB Peripheral

Abhishek Chauhan — Fri, 27 Apr 2018 07:11:44 GMT

nrf_delay_us(RNG_BYTE_WAIT_US * remaining);

RE: Intro to Application-level Security Using the ECB Peripheral

Raghav Iyer — Thu, 22 Feb 2018 10:47:50 GMT

Hi,

Thanks for the great article. I was wondering if we can use nrf_crypto_ecdh_shared_secret_compute for generating the shared secret keys?

The shared secret generated using above function is 32 bytes but the above requires only 16 bytes for key. Is it safe to use only the first or last 16 bytes to encrypt the nonce?

Thanks,

Raghav

RE: Intro to Application-level Security Using the ECB Peripheral

Jebakumar — Thu, 18 May 2017 08:33:31 GMT

Hi Daniel,

Good article and explained well.

Thanks a lot.

RE: Intro to Application-level Security Using the ECB Peripheral

adriand — Wed, 28 Dec 2016 08:31:05 GMT

Hello,

thanks for a nice tutorial. However, I've got a hard fault when nrf_ecb_hal_data_t m_ecb_datawas not aligned. To fix this in Keil I used attribute: static nrf_ecb_hal_data_t m_ecb_data __attribute__((aligned (4)));

I also have a question, what if two devices (with the same pre-shared private key) went out of sync with their counters?

What would be safe to inform each other about that and set a new common counter value by unencrypted channel? Is it very unsafe if someone (possible hijacker) could guess the counter values for following encrypted messages? Or without private key this is useless for him?

Thanks!

RE: Intro to Application-level Security Using the ECB Peripheral

Daniel Veilleux — Wed, 31 Aug 2016 23:01:10 GMT

Hello Kacem,

The cleartext ([COUNTER][NONCE]) buffer is encrypted to create the ciphertext. The ciphertext is then XOR'd, one byte at a time, with the message that Alice and Bob want to trade. Applying the XOR function twice yields the original buffer so Alice and Bob just need to have the same NONCE and keep their counters in sync.

RE: Intro to Application-level Security Using the ECB Peripheral

Jeong Hyun Seok — Tue, 16 Aug 2016 04:38:10 GMT

Thank you.

RE: Intro to Application-level Security Using the ECB Peripheral

Kacemox — Thu, 04 Feb 2016 09:00:45 GMT

Great artical !

the clear text contains the nonce value; 12 random bytes starting at index 4 and the counter value starting at index 0.

but I didn't understand what the cipher text contains ? what I understand is that the buf contains the message and the ciphertext contains the result of the xor operation with output buffer from the ECB, but this line of code "buf[i] ^= m_ecb_data.ciphertext[i];" doesn't fit with Alice's and Bob's e.g.

Best regards,

Kacem.

RE: Intro to Application-level Security Using the ECB Peripheral

Eirik Midttun — Mon, 27 Jul 2015 07:08:13 GMT

Great article! Where is the "Like" button?

RE: Intro to Application-level Security Using the ECB Peripheral

syntroniks — Fri, 24 Jul 2015 14:29:57 GMT

Great writeup, next up: ECDH! Great explanation using CBC.

RE: Intro to Application-level Security Using the ECB Peripheral

David Edwin — Thu, 23 Jul 2015 08:07:13 GMT

Good intro Thanks for sharing.