Identification of equivalent current source of cryptographic circuit based on impedance and current measurements at board level

Kaoru Okamoto, Tetsuo Amano, Kengo Iokibe, Yoshitaka Toyota

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)


Side-channel attacks are a kind of cryptanalytic attacks by means of the electric current in the range of radio frequency (RF) leaking out from a cryptographic integrated circuit (IC) and/or the electromagnetic radiation generated by the RF power current. The RF power current is caused by simultaneous switching activities of logic gates during an encryption process operated in the cryptographic IC. The RF power current is a major cause of the electromagnetic interference (EMI). To decrease the RF power current at PCB level can lead to decrease designing costs. As a preparation of applying LECCS models to a cryptographic IC for estimating the RF power current occurred during an encryption process, the model parameters were identified from measurements in this paper. The LECCS models were composed of a current source that expressed the RF power current occurred in the cryptographic circuit and a passive network. The current source identified grown in amplitude 200 ns after the beginning of the encryption process. This agreed to the beginning of the target round. In frequency domain, current spectra were seen at 24 MHz and its harmonics. The authors obtained waveforms of the RF power current from analog circuit simulations with the LECCS model identified, and validated the cryptographic device in security against the side-channel attacks by means of the correlation power analysis (CPA) method. Results of CPA with the simulated waveforms were consistent to CPA results with measured waveforms. These results means that model parameters were identified correctly, and suggests that the LECCS model is effective for validation of cryptographic devices with respect to side-channel attacks.

Original languageEnglish
Title of host publicationProceedings of the SICE Annual Conference
Number of pages6
Publication statusPublished - 2012
Event2012 51st Annual Conference on of the Society of Instrument and Control Engineers of Japan, SICE 2012 - Akita, Japan
Duration: Aug 20 2012Aug 23 2012


Other2012 51st Annual Conference on of the Society of Instrument and Control Engineers of Japan, SICE 2012



  • LECCS model
  • radio frequency (RF) power current
  • side-channel attack

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Control and Systems Engineering
  • Computer Science Applications

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