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Security on the Line: Modern Curve-based Cryptography Joost Renes - PowerPoint PPT Presentation

Security on the Line: Modern Curve-based Cryptography Joost Renes SCA Workshop 18 June 2019 Modern curve-based cryptography Modern curve-based cryptography 1 / 11 Modern curve-based cryptography Internet of Things Size & speed


  1. Security on the Line: Modern Curve-based Cryptography Joost Renes SCA Workshop 18 June 2019

  2. Modern curve-based cryptography “Modern” curve-based cryptography 1 / 11

  3. Modern curve-based cryptography Internet of Things Size & speed ... Genus 2 Kummer varieties “Modern” curve-based cryptography 1 / 11

  4. Modern curve-based cryptography Classical setting (Ben Smith’s talk) Internet of Things Size & speed ... Genus 2 Kummer varieties “Modern” curve-based cryptography 1 / 11

  5. Modern curve-based cryptography Classical setting (Ben Smith’s talk) Internet of Things Size & speed ... Genus 2 Kummer varieties “Modern” curve-based cryptography Isogeny-based cryptography 1 / 11

  6. Elliptic curves in cryptography Discrete-log-based elliptic-curve cryptography [Mil86; Kob87] 2 / 11

  7. Elliptic curves in cryptography Discrete-log-based elliptic-curve cryptography [Mil86; Kob87] Ordinary isogeny-based group actions [Cou06; RS06; DKS18] 2 / 11

  8. Elliptic curves in cryptography Discrete-log-based elliptic-curve cryptography [Mil86; Kob87] Ordinary isogeny-based group actions [Cou06; RS06; DKS18] Supersingular isogeny-based cryptography / F p 2 [CLG09; JF11] 2 / 11

  9. Elliptic curves in cryptography Discrete-log-based elliptic-curve cryptography [Mil86; Kob87] Ordinary isogeny-based group actions [Cou06; RS06; DKS18] Supersingular isogeny-based cryptography / F p 2 [CLG09; JF11] Supersingular isogeny-based group actions / F p [Cas+18] 2 / 11

  10. Elliptic curves & isogenies (1) Fixed: prime p E a , b : y 2 = x 3 + ax + b 3 / 11

  11. Elliptic curves & isogenies (1) Fixed: prime p E c , d : y 2 = x 3 + cx + d E a , b : y 2 = x 3 + ax + b 3 / 11

  12. Elliptic curves & isogenies (1) Fixed: prime p  isogeny    x �→ f ( x ) / g ( x ) , y �→ . . .      E c , d : y 2 = x 3 + cx + d E a , b : y 2 = x 3 + ax + b 3 / 11

  13. Elliptic curves & isogenies (1) Fixed: prime p  ℓ -isogeny    x �→ f ( x ) / g ( x ) , y �→ . . .  with deg ( f ) = ℓ     and deg ( g ) = ℓ − 1 E c , d : y 2 = x 3 + cx + d E a , b : y 2 = x 3 + ax + b 3 / 11

  14. Elliptic curves & isogenies (1) Fixed: prime p  1-isogeny    x �→ f ( x ) / g ( x ) , y �→ . . .  with deg ( f ) = 1     and deg ( g ) = 0 E c , d : y 2 = x 3 + cx + d E a , b : y 2 = x 3 + ax + b 3 / 11

  15. Elliptic curves & isogenies (1) Fixed: prime p  2-isogeny    x �→ f ( x ) / g ( x ) , y �→ . . .  with deg ( f ) = 2     and deg ( g ) = 1 E c , d : y 2 = x 3 + cx + d E a , b : y 2 = x 3 + ax + b 3 / 11

  16. Elliptic curves & isogenies (1) Fixed: prime p  3-isogeny    x �→ f ( x ) / g ( x ) , y �→ . . .  with deg ( f ) = 3     and deg ( g ) = 2 E c , d : y 2 = x 3 + cx + d E a , b : y 2 = x 3 + ax + b 3 / 11

  17. Elliptic curves & isogenies (1) Fixed: prime p  5-isogeny    x �→ f ( x ) / g ( x ) , y �→ . . .  with deg ( f ) = 5     and deg ( g ) = 4 E c , d : y 2 = x 3 + cx + d E a , b : y 2 = x 3 + ax + b 3 / 11

  18. Elliptic curves & isogenies (1) Fixed: prime p  7-isogeny    x �→ f ( x ) / g ( x ) , y �→ . . .  with deg ( f ) = 7     and deg ( g ) = 6 E c , d : y 2 = x 3 + cx + d E a , b : y 2 = x 3 + ax + b 3 / 11

  19. Elliptic curves & isogenies (1) Fixed: prime p  11-isogeny    x �→ f ( x ) / g ( x ) , y �→ . . .  with deg ( f ) = 11     and deg ( g ) = 10 E c , d : y 2 = x 3 + cx + d E a , b : y 2 = x 3 + ax + b 3 / 11

  20. Elliptic curves & isogenies (1) Fixed: prime p  13-isogeny    x �→ f ( x ) / g ( x ) , y �→ . . .  with deg ( f ) = 13     and deg ( g ) = 12 E c , d : y 2 = x 3 + cx + d E a , b : y 2 = x 3 + ax + b 3 / 11

  21. Elliptic curves & isogenies (1) Fixed: prime p , End F p ( E a , b ) = O Q ( π ) 3 / 11

  22. Elliptic curves & isogenies (1) Fixed: prime p , End F p ( E a , b ) = O Q ( π ) , ℓ = 2 3 / 11

  23. Elliptic curves & isogenies (1) Fixed: prime p , End F p ( E a , b ) = O Q ( π ) , ℓ = 2 3 / 11

  24. Elliptic curves & isogenies (1) Fixed: prime p , End F p ( E a , b ) = O Q ( π ) , ℓ = 2 3 / 11

  25. Elliptic curves & isogenies (1) Fixed: prime p , End F p ( E a , b ) = O Q ( π ) , ℓ = 3 3 / 11

  26. Elliptic curves & isogenies (1) Fixed: prime p , End F p ( E a , b ) = O Q ( π ) , ℓ = 5 3 / 11

  27. Elliptic curves & isogenies (1) Fixed: prime p , End F p ( E a , b ) = O Q ( π ) , ℓ = 7 3 / 11

  28. Elliptic curves & isogenies (1) Fixed: prime p , End F p ( E a , b ) = O Q ( π ) , ℓ = 11 3 / 11

  29. Elliptic curves & isogenies (1) Fixed: prime p , End F p ( E a , b ) = O Q ( π ) , ℓ = 13 3 / 11

  30. Elliptic curves & isogenies (2) 2 4 / 11

  31. Elliptic curves & isogenies (2) 2 4 / 11

  32. Elliptic curves & isogenies (2) 2 4 / 11

  33. Elliptic curves & isogenies (2) 2 4 / 11

  34. Elliptic curves & isogenies (2) 2 4 / 11

  35. Elliptic curves & isogenies (2) 3 4 / 11

  36. Elliptic curves & isogenies (2) 3 4 / 11

  37. Elliptic curves & isogenies (2) 3 4 / 11

  38. Elliptic curves & isogenies (2) 3 4 / 11

  39. Elliptic curves & isogenies (2) 3 4 / 11

  40. Elliptic curves & isogenies (2) 5 4 / 11

  41. Elliptic curves & isogenies (2) 7 4 / 11

  42. Isogeny volcanoes 2 3 5 7 11 13 5 / 11

  43. Isogeny-based cryptography (1) 2 6 / 11

  44. Isogeny-based cryptography (1) 2 6 / 11

  45. Isogeny-based cryptography (1) 3 6 / 11

  46. Isogeny-based cryptography (1) 3 6 / 11

  47. Isogeny-based cryptography (1) 5 6 / 11

  48. Isogeny-based cryptography (1) 5 6 / 11

  49. Isogeny-based cryptography (1) 2 3 5 7 11 13 6 / 11

  50. Isogeny-based cryptography (1) 6 / 11

  51. Isogeny-based cryptography (1) # primes: 1 Work (per prime): ≤ t Work (total): ≤ t Entropy: t 6 / 11

  52. Isogeny-based cryptography (1) # primes: 1 Work (per prime): ≤ t Work (total): ≤ t Entropy: t 6 / 11

  53. Isogeny-based cryptography (1) # primes: 1 Work (per prime): ≤ t Work (total): ≤ t Entropy: t 6 / 11

  54. Isogeny-based cryptography (1) # primes: 2 Work (per prime): ≤ t Work (total): ≤ 2 · t t 2 Entropy: 6 / 11

  55. Isogeny-based cryptography (1) # primes: 3 Work (per prime): ≤ t Work (total): ≤ 3 · t t 3 Entropy: 6 / 11

  56. Isogeny-based cryptography (1) # primes: 4 Work (per prime): ≤ t Work (total): ≤ 4 · t t 4 Entropy: 6 / 11

  57. Isogeny-based cryptography (1) # primes: 5 Work (per prime): ≤ t Work (total): ≤ 5 · t t 5 Entropy: 6 / 11

  58. Isogeny-based cryptography (1) # primes: 6 Work (per prime): ≤ t Work (total): ≤ 6 · t t 6 Entropy: 6 / 11

  59. Isogeny-based cryptography (1) # primes: L Work (per prime): ≤ t Work (total): ≤ L · t t L Entropy: 6 / 11

  60. OIDH & CSIDH Two different ways to instantiate; 1. Ordinary isogeny Diffie–Hellman (OIDH) 2. Supersingular isogeny Diffie–Hellman (CSIDH) The idea for OIDH first by Couveignes in ’96 [Cou06] = ⇒ Post-quantum security with very small keys [DKS18] = ⇒ CSIDH almost identical but easier to instantiate [Cas+18] 7 / 11

  61. State of CSIDH ( ∼ NIST level I security) 1. CSIDH key exchange ◮ Non-interactive with 64-byte public keys ◮ ∼ 80 ms for full exchange (not constant-time) 8 / 11

  62. State of CSIDH ( ∼ NIST level I security) 1. CSIDH key exchange ◮ Non-interactive with 64-byte public keys ◮ ∼ 80 ms for full exchange (not constant-time) 2. Constant-time implementations [MCR18] (at ∼ 246 ms) 8 / 11

  63. State of CSIDH ( ∼ NIST level I security) 1. CSIDH key exchange ◮ Non-interactive with 64-byte public keys ◮ ∼ 80 ms for full exchange (not constant-time) 2. Constant-time implementations [MCR18] (at ∼ 246 ms) 3. SeaSign signatures [DG19] large and/or slow 8 / 11

  64. State of CSIDH ( ∼ NIST level I security) 1. CSIDH key exchange ◮ Non-interactive with 64-byte public keys ◮ ∼ 80 ms for full exchange (not constant-time) 2. Constant-time implementations [MCR18] (at ∼ 246 ms) 3. SeaSign signatures [DG19] large and/or slow 4. CSI-FiSh signatures [BKV19] smaller and faster (small p ) 8 / 11

  65. State of CSIDH ( ∼ NIST level I security) 1. CSIDH key exchange ◮ Non-interactive with 64-byte public keys ◮ ∼ 80 ms for full exchange (not constant-time) 2. Constant-time implementations [MCR18] (at ∼ 246 ms) 3. SeaSign signatures [DG19] large and/or slow 4. CSI-FiSh signatures [BKV19] smaller and faster (small p ) 5. Bunch of cryptanalysis [BS18; Ber+19] ◮ Quantum subexponential attacks! 8 / 11

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