• On provably secure time-stamping schemesBuldas, Ahto; Saarepera, MärtAdvances in cryptology - ASIACRYPT 2004 : 10th International Conference on the Theory and Application of Cryptology and Information Security : Jeju Island, Korea, December 5-9, 2004 : proceedings2004 / p. 500-514 : ill https://link.springer.com/chapter/10.1007/978-3-540-30539-2_35