chamhash_adm05

Ateniese-Medeiros Chameleon Hash (ADM05)

Authors: Giuseppe Ateniese, Breno de Medeiros

Title: “On the Key Exposure Problem in Chameleon Hashes”

Published in: SCN 2004

Notes: Section 4, Schnorr group-based construction

Scheme Properties

• Type: chameleon hash function

• Setting: Schnorr groups

• Assumption: DL

Implementation

Authors:

10. Ayo Akinyele

Date:

4/2011

class chamhash_adm05.ChamHash_Adm05(p=0, q=0)

Bases: ChamHash

>>> from charm.core.math.integer import integer
>>> p = integer(141660875619984104245410764464185421040193281776686085728248762539241852738181649330509191671665849071206347515263344232662465937366909502530516774705282764748558934610432918614104329009095808618770549804432868118610669336907161081169097403439689930233383598055540343198389409225338204714777812724565461351567)
>>> q = integer(70830437809992052122705382232092710520096640888343042864124381269620926369090824665254595835832924535603173757631672116331232968683454751265258387352641382374279467305216459307052164504547904309385274902216434059305334668453580540584548701719844965116691799027770171599194704612669102357388906362282730675783)
>>> chamHash = ChamHash_Adm05(p, q)
>>> (public_key, secret_key) = chamHash.paramgen()
>>> msg = "hello world this is the message"
>>> c = chamHash.hash(public_key, msg)
>>> c == chamHash.hash(public_key, msg, c[1], c[2])
True

find_collision(pk, sk, C, new_message)

hash(pk, m, r=0, s=0)

paramgen(secparam=1024)

chamhash_adm05.main()