Class: H2C::Suite

Inherits:
Object
  • Object
show all
Defined in:
lib/h2c/suite.rb

Overview

Hash to curve suites

Constant Summary collapse

SECP256K1_XMDSHA256_SSWU_NU_ = 
"secp256k1_XMD:SHA-256_SSWU_NU_"
SECP256K1_XMDSHA256_SSWU_RO_ = 
"secp256k1_XMD:SHA-256_SSWU_RO_"
BLS12381G1_XMDSHA256_SSWU_NU_ = 
"BLS12381G1_XMD:SHA-256_SSWU_NU_"
BLS12381G1_XMDSHA256_SSWU_RO_ = 
"BLS12381G1_XMD:SHA-256_SSWU_RO_"
P256_XMDSHA256_SSWU_NU_ = 
"P256_XMD:SHA-256_SSWU_NU_"
P256_XMDSHA256_SSWU_RO_ = 
"P256_XMD:SHA-256_SSWU_RO_"
P384_XMDSHA384_SSWU_NU_ = 
"P384_XMD:SHA-384_SSWU_NU_"
P384_XMDSHA384_SSWU_RO_ = 
"P384_XMD:SHA-384_SSWU_RO_"
P521_XMDSHA512_SSWU_NU_ = 
"P521_XMD:SHA-512_SSWU_NU_"
P521_XMDSHA512_SSWU_RO_ = 
"P521_XMD:SHA-512_SSWU_RO_"

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(id, dst) ⇒ Suite

Initialize suite

Parameters:

  • id (String) —

    Suite id.

  • dst (String) —

    Domain separation tag.



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# File 'lib/h2c/suite.rb', line 21

def initialize(id, dst)
  @id = id
  @k = 128
  @m = 1
  case id
  when SECP256K1_XMDSHA256_SSWU_NU_, SECP256K1_XMDSHA256_SSWU_RO_
    @curve = ECDSA::Group::Secp256k1
    @exp = Expander.get(HashFunc::SHA256, dst, @k)
    @l = 48
    @map = M2C::SSWUAB0.new(H2C::M2C::ISOGeny::Secp256k1.new, -11)
    @ro = (id == SECP256K1_XMDSHA256_SSWU_RO_)
  when BLS12381G1_XMDSHA256_SSWU_NU_, BLS12381G1_XMDSHA256_SSWU_RO_
    @curve = BLS::Group::BLS12381G1
    @exp = Expander.get(HashFunc::SHA256, dst, @k)
    @l = 64
    @map = M2C::SSWUAB0.new(H2C::M2C::ISOGeny::BLS12381G1.new, 11)
    @ro = (id == BLS12381G1_XMDSHA256_SSWU_RO_)
  when P256_XMDSHA256_SSWU_NU_, P256_XMDSHA256_SSWU_RO_
    @curve = ECDSA::Group::Nistp256
    @exp = Expander.get(HashFunc::SHA256, dst, @k)
    @l = 48
    @map = M2C::SSWU.new(ECDSA::Group::Nistp256, -10)
    @ro = (id == P256_XMDSHA256_SSWU_RO_)
  when P384_XMDSHA384_SSWU_NU_, P384_XMDSHA384_SSWU_RO_
    @k = 192
    @curve = ECDSA::Group::Nistp384
    @exp = Expander.get(HashFunc::SHA384, dst, @k)
    @l = 72
    @map = M2C::SSWU.new(ECDSA::Group::Nistp384, -12)
    @ro = (id == P384_XMDSHA384_SSWU_RO_)
  when P521_XMDSHA512_SSWU_NU_, P521_XMDSHA512_SSWU_RO_
    @k = 256
    @curve = ECDSA::Group::Nistp521
    @exp = Expander.get(HashFunc::SHA512, dst, @k)
    @l = 98
    @map = M2C::SSWU.new(ECDSA::Group::Nistp521, -4)
    @ro = (id == P521_XMDSHA512_SSWU_RO_)
  else
    raise H2C::Error, "suite #{curve} unsupported."
  end
end

Instance Attribute Details

#curve ⇒ Object (readonly)

Returns the value of attribute curve.



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# File 'lib/h2c/suite.rb', line 5

def curve
  @curve
end

#exp ⇒ Object (readonly)

Returns the value of attribute exp.



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# File 'lib/h2c/suite.rb', line 5

def exp
  @exp
end

#id ⇒ Object (readonly)

Returns the value of attribute id.



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# File 'lib/h2c/suite.rb', line 5

def id
  @id
end

#k ⇒ Object (readonly)

Returns the value of attribute k.



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# File 'lib/h2c/suite.rb', line 5

def k
  @k
end

#l ⇒ Object (readonly)

Returns the value of attribute l.



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# File 'lib/h2c/suite.rb', line 5

def l
  @l
end

#m ⇒ Object (readonly)

Returns the value of attribute m.



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# File 'lib/h2c/suite.rb', line 5

def m
  @m
end

#map ⇒ Object (readonly)

Returns the value of attribute map.



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# File 'lib/h2c/suite.rb', line 5

def map
  @map
end

#ro ⇒ Object (readonly)

Returns the value of attribute ro.



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# File 'lib/h2c/suite.rb', line 5

def ro
  @ro
end