pksig_waters05

Naccache Identity-Based Signature (N04)

Authors: D. Naccache

Title: “Secure and Practical Identity-Based Encryption”

Published in: IET Information Security, 2005

Available from: http://eprint.iacr.org/2005/369.pdf

Notes: Section 4. Optimized with pre-computed pairings and swapped g1/g2.

Scheme Properties

• Type: signature (identity-based)

• Setting: bilinear groups (asymmetric)

• Assumption: DBDH

Implementation

Authors:

Gary Belvin (original), Fan Zhang (improvements)

Date:

06/2011 (original), 3/2013 (improvements)

class pksig_waters05.IBE_N04_Sig(groupObj)

Bases: PKSig

>>> from charm.toolbox.pairinggroup import PairingGroup
>>> group = PairingGroup('SS512')
>>> waters = Waters(group)
>>> ibe = IBE_N04_Sig(group)
>>> (public_key, secret_key) = ibe.keygen()
>>> ID = "bob@example.com"
>>> msg = waters.hash("This is a test.")    
>>> signature = ibe.sign(public_key, secret_key, msg)
>>> ibe.verify(public_key, msg, signature)
True

keygen(l=32)

l is the security parameter with l = 32, and the hash function at 256 bits = n * l with n = 8

sign(pk, sk, m)

v = (v1, .., vn) is an identity

verify(pk, msg, sig)

pksig_waters05.main()