Patent SG-11201805472R-A (SG)
Title: Determining a common secret for the secure exchange of information and hierarchical, deterministic cryptographic keys
IPC: H04L9/08
Filed: 2017-02-16
Abstract: INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (19) World Intellectual Property Organization IIIM141101110101011111 01011111011101011111 100111110111110111110111 III N International Bureau ... .... ..Yjd (10) International Publication Number (43) International Publication Date ..... ...r .....1 WO 2017/145016 Al 31 August 2017 (31.08.2017) WIPO I PCT (51) International Patent Classification: (81) Designated States (unless otherwise indicated, for every GO6Q 20/38 (2012.01) HO4L 9/32 (2006.01) kind of national protection available): AE, AG, AL, AM, H04L 9/30 (2006.01) H04L 9/08 (2006.01) AO, AT, AU, AZ, BA, BB, BG, BH, BN, BR, BW, BY, BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DJ, DK, DM, (21) International Application Number: DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, PCT/IB2017/050856 HN, HR, HU, ID, IL, IN, IR, IS, JP, KE, KG, KH, KN, (22) International Filing Date: KP, KR, KW, KZ, LA, LC, LK, LR, LS, LU, LY, MA, 16 February 2017 (16.02.2017) MD, ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, OM, PA, PE, PG, PH, PL, PT, QA, RO, RS, (25) Filing Language: English RU, RW, SA, SC, SD, SE, SG, SK, SL, SM, ST, SV, SY, (26) Publication Language: English TH, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW. (30) Priority Data: 1603117.1 23 February 2016 (23.02.2016) GB (84) Designated States (unless otherwise indicated, for every 1619301.3 15 November 2016 (15.11.2016) GB kind of regional protection available): ARIPO (BW, GH, GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, ST, SZ, (71) Applicant: NCHAIN HOLDINGS LIMITED [AG/AG]; TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU, Fitzgerald House, 44 Church Street, St. John's (AG). TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, (72) Inventors: WRIGHT, Craig Steven; c/o Urquhart-Dykes & Lord LLP, 7th Floor Churchill House, Churchill Way, LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, Cardiff CF10 2HH (GB). SAVANAH, Stephane; c/o Ur- quhart-Dykes & Lord LLP, 7th Floor Churchill House, GW, KM, ML, MR, NE, SN, TD, TG). = Churchill Way, Cardiff CF10 2HH (GB). [Continued on next page] = (54) Title: DETERMINING A COMMON SECRET FOR THE SECURE EXCHANGE OF INFORMATION AND HIERARCHIC- _ AL, DETERMINISTIC CRYPTOGRAPHIC KEYS _ (57) : A method (300) and system (1) of determining a common _ secret for two nodes (3, 7). Each node (3, 7) has a respective asymmetric = cryptography pair, each pair including a master private key and a master = _ = — = Third node lc is 111 IOW public key. Respective second private and public keys may be determ- fined based on the master private key, master public key and a determin- —19 istic key. A common secret may be determined at each of the nodes based on the second private and public keys. In one example, a node (3, 7) may determine the common secret based on (i) a second private key based on the node's own master private key and the deterministic key; 3 = and (ii) a second public key based on the other node's master public key = = and the deterministic key. The invention may be suited for use with, but = — 27 not limited to, digital wallets, blockchain (e.g. Bitcoin) technologies and personal device security. t ti - 23 Second First node node = — '-'-r--' L \, Is _ 1-1 .4 11 kin ii- ,-1 IN ,-1 © ei Mc . Pic . 1)1 = r 13 1 1 5 Fig. P is Eavesdropper 1 ii 17 lc O WO 2017/145016 Al 1#11101M01101DEIROIDEOM01011111001111101111MOVOIS Published: — with international search report (Art. 21(3))