An identity-based multisignature scheme and an identity-based aggregate signature scheme are proposed in this paper. They are both from m-torsion groups on super-singular elliptic curves or hyper-elliptic curves and b...An identity-based multisignature scheme and an identity-based aggregate signature scheme are proposed in this paper. They are both from m-torsion groups on super-singular elliptic curves or hyper-elliptic curves and based on the recently proposed identity-based signature scheme of Cha and Cheon. Due to the sound properties of m-torsion groups and the base scheme, it turns out that our schemes are very simple and efficient. Both schemes are proven to be secure against adaptive chosen message attack in the random oracle model under the normal security notions with the assumption that the Computational Diffie-Hellman problem is hard in the m-torsion groups.展开更多
Threshold blind signature is playing an important role in cryptography as well as in practical applications such as e-cash and e-voting systems, etc. In this paper, we present an efficient and practical threshold bind...Threshold blind signature is playing an important role in cryptography as well as in practical applications such as e-cash and e-voting systems, etc. In this paper, we present an efficient and practical threshold bind signature from Weil pairing on super-singular elliptic curves or hyper-elliptic curves over finite field and prove that our scheme is provably secure in the random oracle model.展开更多
LetE=E σ :y 2 =x(x+σp)(x+σq) be elliptic curves, where σ= ±1,p andq are prime numbers withp + 2= q. (i) Selmer groups S2(E/Q), S03D5(E/Q), and $S^{\widehat{(\varphi )}} \left( {E/Q} \right)$ are explicitly de...LetE=E σ :y 2 =x(x+σp)(x+σq) be elliptic curves, where σ= ±1,p andq are prime numbers withp + 2= q. (i) Selmer groups S2(E/Q), S03D5(E/Q), and $S^{\widehat{(\varphi )}} \left( {E/Q} \right)$ are explicitly determined, e.g. S2(E+1/Q)= (Z/2Z)2, (Z/2Z)3, and (Z/2Z)4 when p ≡ 5, 1 (or 3), and 7(mod 8), respectively. (ii) Whenp ≡ 5 (3, 5 for σ= ?1) (mod 8), it is proved that the Mordell-Weil group E(Q) ? Z/2Z ⊕ Z/2Z, rankE(Q) = 0, and Shafarevich-Tate group III (E/Q)[2]= 0. (iii) In any case, the sum of rankE(Q) and dimension of III (E/Q)[2] is given, e.g. 0, 1, 2 whenp ≡ 5, 1 (or 3), 7 (mod 8) for σ= 1. (iv) The Kodaira symbol, the torsion subgroup E(K)tors for any number fieldK, etc. are also obtained.展开更多
We prove the existence and nonexistence of elliptic curves having good reduction everywhere over certain real quadratic fields Q(m) for m≤200. These results of computations give best-possible data including structure...We prove the existence and nonexistence of elliptic curves having good reduction everywhere over certain real quadratic fields Q(m) for m≤200. These results of computations give best-possible data including structures of Mordell-Weil groups over some real quadratic fields via two-descent. We also prove similar results for the case of certain cubic fields. Especially, we give the first example of elliptic curve having everywhere good reduction over a pure cubic field using our method.展开更多
In this work, we use the finiteness of the Mordell-weil group and the Riemann Roch spaces to give a geometric parametrization of the set of algebraic points of any given degree over the field of rational numbers Q on ...In this work, we use the finiteness of the Mordell-weil group and the Riemann Roch spaces to give a geometric parametrization of the set of algebraic points of any given degree over the field of rational numbers Q on curve C<sub>3 </sub>(11): y<sup>11</sup> = x<sup>3</sup> (x-1)<sup>3</sup>. This result is a special case of quotients of Fermat curves C<sub>r,s </sub>(p) : y<sup>p</sup> = x<sup>r</sup>(x-1)<sup>s</sup>, 1 ≤ r, s, r + s ≤ p-1 for p = 11 and r = s = 3. The results obtained extend the work of Gross and Rohrlich who determined the set of algebraic points on C<sub>1</sub>(11)(K) of degree at most 2 on Q.展开更多
In this paper,we calculate the ()-Selmer groups S()(E/Q) and S()(E/Q) of elliptic curves y2 = x(x + εpD)(x + εqD) via the descent method.In particular,we show that the Selmer groups of several families of such ellip...In this paper,we calculate the ()-Selmer groups S()(E/Q) and S()(E/Q) of elliptic curves y2 = x(x + εpD)(x + εqD) via the descent method.In particular,we show that the Selmer groups of several families of such elliptic curves can be arbitrary large.展开更多
基金Supported by the National 973 Project of China (No.G1999035803), the National Natural Science Foundation of China (No.60373104) and the National 863 Project of China (No.2002AA143021).
文摘An identity-based multisignature scheme and an identity-based aggregate signature scheme are proposed in this paper. They are both from m-torsion groups on super-singular elliptic curves or hyper-elliptic curves and based on the recently proposed identity-based signature scheme of Cha and Cheon. Due to the sound properties of m-torsion groups and the base scheme, it turns out that our schemes are very simple and efficient. Both schemes are proven to be secure against adaptive chosen message attack in the random oracle model under the normal security notions with the assumption that the Computational Diffie-Hellman problem is hard in the m-torsion groups.
文摘Threshold blind signature is playing an important role in cryptography as well as in practical applications such as e-cash and e-voting systems, etc. In this paper, we present an efficient and practical threshold bind signature from Weil pairing on super-singular elliptic curves or hyper-elliptic curves over finite field and prove that our scheme is provably secure in the random oracle model.
基金This work ws supported by the National Natural Science Foundation of China(Grant No.10071041).
文摘LetE=E σ :y 2 =x(x+σp)(x+σq) be elliptic curves, where σ= ±1,p andq are prime numbers withp + 2= q. (i) Selmer groups S2(E/Q), S03D5(E/Q), and $S^{\widehat{(\varphi )}} \left( {E/Q} \right)$ are explicitly determined, e.g. S2(E+1/Q)= (Z/2Z)2, (Z/2Z)3, and (Z/2Z)4 when p ≡ 5, 1 (or 3), and 7(mod 8), respectively. (ii) Whenp ≡ 5 (3, 5 for σ= ?1) (mod 8), it is proved that the Mordell-Weil group E(Q) ? Z/2Z ⊕ Z/2Z, rankE(Q) = 0, and Shafarevich-Tate group III (E/Q)[2]= 0. (iii) In any case, the sum of rankE(Q) and dimension of III (E/Q)[2] is given, e.g. 0, 1, 2 whenp ≡ 5, 1 (or 3), 7 (mod 8) for σ= 1. (iv) The Kodaira symbol, the torsion subgroup E(K)tors for any number fieldK, etc. are also obtained.
文摘We prove the existence and nonexistence of elliptic curves having good reduction everywhere over certain real quadratic fields Q(m) for m≤200. These results of computations give best-possible data including structures of Mordell-Weil groups over some real quadratic fields via two-descent. We also prove similar results for the case of certain cubic fields. Especially, we give the first example of elliptic curve having everywhere good reduction over a pure cubic field using our method.
基金supported by the Natural Science Foundation of Jiangsu Province(Nos.BK20181427,BK20211305)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX22_3180)。
文摘In this work, we use the finiteness of the Mordell-weil group and the Riemann Roch spaces to give a geometric parametrization of the set of algebraic points of any given degree over the field of rational numbers Q on curve C<sub>3 </sub>(11): y<sup>11</sup> = x<sup>3</sup> (x-1)<sup>3</sup>. This result is a special case of quotients of Fermat curves C<sub>r,s </sub>(p) : y<sup>p</sup> = x<sup>r</sup>(x-1)<sup>s</sup>, 1 ≤ r, s, r + s ≤ p-1 for p = 11 and r = s = 3. The results obtained extend the work of Gross and Rohrlich who determined the set of algebraic points on C<sub>1</sub>(11)(K) of degree at most 2 on Q.
文摘In this paper,we calculate the ()-Selmer groups S()(E/Q) and S()(E/Q) of elliptic curves y2 = x(x + εpD)(x + εqD) via the descent method.In particular,we show that the Selmer groups of several families of such elliptic curves can be arbitrary large.
