Charles Guillemet

CTO at Ledger

Charles Guillemet Bio

Charles Guillemet is a French engineer and cryptography expert. He holds a Master of Science in Cryptography and Security from the Engineering School ENSIMAG, where he graduated as valedictorian. He also served as a lecturer at ENSIMAG.

Early Career

Guillemet began his career at Tiempo, an innovative startup in the secure industry, where he was responsible for designing the security of EAL5+ secure integrated circuits. His work at Tiempo laid the foundation for his expertise in hardware security and cryptography.

Career at CEA

Following his tenure at Tiempo, Guillemet worked as a Technical Manager at an Information Technology Security Evaluation Facility (ITSEF) within the CEA, a French research organization specializing in energy, defense and security, information technologies, and health technologies. In this role, he focused on the evaluation and validation of security technologies.


In 2017, Guillemet joined Ledger, a leading company in the field of cryptocurrency hardware wallets, as Chief Security Officer. His extensive background in cryptography and hardware security played a crucial role in enhancing Ledger’s security protocols. In 2019, he was promoted to Chief Technology Officer, where he continues to oversee the development of secure and innovative technologies for cryptocurrency storage and management.

Contributions and Impact

As CTO of Ledger, Guillemet has been instrumental in advancing the company’s technological capabilities, ensuring the highest standards of security for its products. His leadership and expertise have significantly contributed to Ledger’s reputation as a trusted name in the cryptocurrency industry.

Charles Guillemet’s career reflects his deep commitment to cryptography and security, making him a key figure in the development of secure technologies for the digital age.

Charles Guillemet News

Charles Guillemet Current Work

Charles Guillemet Previous Work

  • Ledger Chief Security Officer Dec 2017 - July 2019
  • CEA - Commissariat à l'énergie atomique et aux énergies alternatives Technical Manager (Apr 2015 - Dec 2017), CESTI - Cryptography & Security Evaluator (Feb 2014 - Apr 2015)
  • Grenoble INP - Ensimag Teaching - SmartCard Security - Master II Oct 2015 - Oct 2017
  • Tiempo S.A.S. Cryptosystems Design Expert Oct 2009 - Feb 2014

Charles Guillemet Education

  • National School of Computer Science and Applied Mathematics of Grenoble, Mathematics and Computer Science, 2007 - 2009
  • Université Joseph Fourier (Grenoble I), Master 2, Security , Cryptology and Coding of Information systems, 2009 - 2010
  • Université montpellier 2, Maitrise (Master 1), Mathematics, 2003 - 2007

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