Class: FROST::Signature

Inherits:
Object
  • Object
show all
Defined in:
lib/frost/signature.rb

Overview

A Schnorr signature over some prime order group (or subgroup).

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(context, r, s) ⇒ Signature

Constructor

Parameters:

  • context (FROST::Context)
  • r (ECDSA::Point) —

    Public nonce of signature.

  • s (Integer) —

    Scalar value of signature.

Raises:

  • (ArgumentError) 


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# File 'lib/frost/signature.rb', line 12

def initialize(context, r, s)
  raise ArgumentError, "r must be ECDSA::Point" unless r.is_a?(ECDSA::Point)
  raise ArgumentError, "s must be Integer" unless s.is_a?(Integer)
  raise ArgumentError, "context must be FROST::Context" unless context.is_a?(FROST::Context)

  @r = r
  @s = s
  @context = context
end

Instance Attribute Details

#context ⇒ Object (readonly)

Returns the value of attribute context.



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# File 'lib/frost/signature.rb', line 6

def context
  @context
end

#r ⇒ Object (readonly)

Returns the value of attribute r.



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# File 'lib/frost/signature.rb', line 4

def r
  @r
end

#s ⇒ Object (readonly)

Returns the value of attribute s.



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# File 'lib/frost/signature.rb', line 5

def s
  @s
end

Class Method Details

.decode(context, hex_value) ⇒ FROST::Signature

Decode hex value to FROST::Signature.

Parameters:

  • context (FROST::Context)
  • hex_value (String) —

    Hex value of signature.

Returns:

Raises:

  • (ArgumentError) 


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# File 'lib/frost/signature.rb', line 45

def self.decode(context, hex_value)
  raise ArgumentError, "context must be FROST::Context" unless context.is_a?(FROST::Context)
  raise ArgumentError, "hex value must be String" unless hex_value.is_a?(String)

  data = [hex_value].pack("H*")
  data = [0x02].pack('C') + data if context.taproot?
  len = context.group.byte_length + 1

  r = ECDSA::Format::PointOctetString.decode(data[0...len], context.group)
  s = ECDSA::Format::IntegerOctetString.decode(data[len..-1])
  Signature.new(context, r, s)
end

Instance Method Details

#encode ⇒ String

Encode signature to byte string.

Returns:

  • (String) 


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# File 'lib/frost/signature.rb', line 30

def encode
  if context.taproot?
    ECDSA::Format::IntegerOctetString.encode(r.x, context.group.byte_length) +
      ECDSA::Format::IntegerOctetString.encode(s, context.group.byte_length)
  else
    ECDSA::Format::PointOctetString.encode(r, compression: true) +
      ECDSA::Format::IntegerOctetString.encode(s, context.group.byte_length)
  end
end

#to_hex ⇒ String

Encode signature to hex string.

Returns:

  • (String) 


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# File 'lib/frost/signature.rb', line 24

def to_hex
  encode.unpack1("H*")
end