[1] He is the inventor of Keyless Signature Infrastructure, Co-Founder and Chief Scientist at Guardtime and Chair of the OpenKSI foundation.

After graduating from high school, he was conscripted in to the Soviet Army where he spent 2 years as an artillery officer in Siberia.

After being discharged, he started studies in Tallinn University of Technology, where he defended his MSc degree in 1993 and his PhD in 1999.

[2] Buldas was a leading contributor to the Estonian Digital Signature Act and ID-card from 1996 to 2002, currently the only national-level public-key infrastructure (PKI) which has achieved widespread adoption by a country's population for legally binding digital signatures.

His experience of implementing a national level PKI led him to invent Keyless Signature Infrastructure,[4] a digital signature/timestamping system for electronic data that uses only hash-function based cryptography.