- Visited Bauman Moscow State Technical University, Russia during July 2-8, 2017 and delivered the following invited talk on July 6, 2017.
The Title of the talk:
#### Visual Cryptography and DNA Secret Sharing: Two Simple ways to Store Secret Information in a Secure Way.

- Visited School of Computing Tokyo Institute of Technology, Japan June 23, 2016, and delivered the following Invited Talk on June 23, 2016. The Title of the talk:
- Visited University of Nagasaki, Japan June 22, 2016, and delivered the following Invited Talk on June 22, 2016.The Title of the talk:
- Visited University of Kyushu, Japan during June 19-21, 2016 as one of the researcher in the Indian Research Team of the Joint Research Project entitled "Computational Aspects of Mathematical Design and Analysis of Secure Communication Systems Based on Cryptographic Primitives", funded by DST-JSPS.
- Visited International Congress of Mathematicians (ICM 2014), Seoul, Korea August 13-18, 2014 as a recipient of NANUM Travel Grant from ICM . The Title of the presentation:
- Visited University of Putra Malaysia (UPM), Malaysia May 27-30, 2014, and presented the following talk at the International Conference and Workshop on Mathematical Analysis 2014 (ICWOMA2014), 27-30, May 2014. The Title of the talk:
- Visited Graduate School of Mathematical Sciences, University of Tokyo, Japan November 3-6, 2013 as an invited speaker of the JSPS-DST Asian Academic Seminar 2013 on Discrete Mathematics & its Applications, Sunday November 3 - Sunday November 10, 2013. The Title of the three invited talk:
- Visited University of Kyushu, Japan August 26-30, 2013 as an invited speaker of the International Conference entitled "Algebraic constructions as a fundamental keystone of a safe and secure society: Mathematics for guaranteeing the reliability of the cyber-society" organized by the Institute of Mathematics for Industry (IMI), Kyushu University during August 26-30, 2013. The Title of the three invited talks are:
- Visited University of Kyushu, Japan during May 19 to June 6, 2012 as one of the researcher in the Indian Research Team of the Joint Research Project entitled
- Invited and visited to the the Meijo University, Nagoya, Japan during June 3-4, 2012 and delivered a lecture on Micro Array Based DNA Secret Sharing.
Visited University of Kyushu, Japan during August 5 to August 20, 2011 as one of the researcher in the Indian Research Team of the Joint Research Project entitled

#### Analysis of Cryptographic Algorithms and Evaluation on Enhancing Network Security Based on Mathematical Science

- Invited and visited to the Tokyo Institute of Technology, Japan on July 5, 2010 and delivered a lecture on Interdisciplinary Secret Sharing Schemes.
- Invited and visited to the Institute of Industrial Science, the University of Tokyo, Japan on July 7, 2010 and delivered a lecture on
- Visited University of Kyushu, Japan during June 20 to July 10, 2010 as one of the researcher in the Indian Research Team of the Joint Research Project entitled
- Invited and visited to the the Meijo University, Nagoya, Japan on June 9, 2010 and delivered a lecture on
- Invited and visited to the the KDDI R&D Laboratories and had there fruitful discussions with Dr T Tanaka, Senior Manager, Information Security Laboratory, KDDI
- Visited University of Kyushu, Japan during May 24 to June 9, 2009 as one of the researcher in the Indian Research Team of the Joint Research Project entitled
- Visited National Institute of Advanced Industrial Science and Technology (AIST), Research center for information security (RCIS), Japan .
- Visited KDDI R&D Laboratories and had there fruitful discussions with Dr T Tanaka, Senior Manager, Information Security Laboratory, KDDI, Dr K Fukushima and J Kurihara, Associate Research Engineer, Information Security Laboratory, KDDI regarding the efficient implementation of our as well as their schemes of Secret Sharing Schemes.
- Visited Institute of Industrial Science, the University of Tokyo, Japan .
- Visited University of Nagoya, Japan.
- Visited
**University of Linkoping, Sweden**during July 21 to August 4, 2007 and attended a workshop on "DNA and its Related Topics" and delivered a series of Lectures on - Visited on invitation to Paris, France to participate in the Indo-French Workshop on
#### Recent Advances in Cryptography

organized and funded by Indo-French Centre for Promotion of Advanced Research during June 10-June 15, 2007. - Invited talk on "Application of Mathematics in DNA Secret Sharing" at
the
**University of Rajsahi, Bangladesh**on June 14, 2007. - Invited talk on
#### DNA Secret Sharing and its Application to Cryptography

at the Conference DNA and its Related Topics, May 19, 2006, organized by**University of Linkoping, Sweden**. - Invited talk on
#### Applications of Mathematics in Developing Visual Cryptographic Schemes

at the seminar**Laprochaine session du sminaire se tiendra le vendredi**November 4, 2005, organized by**ENSTA, France**. - Invited talk on
#### Application of Mathematics in Cryptography at the conference Mathematics and Its Applications

, 2005, June 22, 2005 organized by**University of Karlstad, Sweden**.

2. Applications of Algebraic Structure in Visual Cryptography (on August 28, 2013).

3. Plaintext Checkable Encryption with Designated Checker (on August 29, 2013).