Class: BlockIo::Key

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

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(privkey = nil, compressed = true) ⇒ Key

Returns a new instance of Key.



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# File 'lib/block_io.rb', line 166

def initialize(privkey = nil, compressed = true)
  # the privkey must be in hex if at all provided

  @group = ECDSA::Group::Secp256k1
  @private_key = privkey.to_i(16) || 1 + SecureRandom.random_number(group.order - 1)
  @public_key = @group.generator.multiply_by_scalar(@private_key)
  @compressed = compressed

end

Class Method Details

.from_passphrase(passphrase) ⇒ Object

Raises:

  • (Exception) 


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# File 'lib/block_io.rb', line 206

def self.from_passphrase(passphrase)
  # create a private+public key pair from a given passphrase
  # think of this as your brain wallet. be very sure to use a sufficiently long passphrase
  # if you don't want a passphrase, just use Key.new and it will generate a random key for you
  
  raise Exception.new('Must provide passphrase at least 8 characters long.') if passphrase.nil? or passphrase.length < 8
  
  hashed_key = Helper.sha256([passphrase].pack("H*")) # must pass bytes to sha256

  return Key.new(hashed_key)
end

.from_wif(wif) ⇒ Object 



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# File 'lib/block_io.rb', line 218

def self.from_wif(wif)
  # returns a new key extracted from the Wallet Import Format provided
  # TODO check against checksum

  hexkey = Helper.decode_base58(wif)
  actual_key = hexkey[2...66]

  compressed = hexkey[2..hexkey.length].length-8 > 64 and hexkey[2..hexkey.length][64...66] == '01'

  return Key.new(actual_key, compressed)

end

Instance Method Details

#deterministicGenerateK(data, privkey, group = ECDSA::Group::Secp256k1) ⇒ Object 



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# File 'lib/block_io.rb', line 237

def deterministicGenerateK(data, privkey, group = ECDSA::Group::Secp256k1)
  # returns a deterministic K  -- RFC6979

  hash = data.bytes.to_a

  x = [privkey.to_s(16)].pack("H*").bytes.to_a
  
  k = []
  32.times { k.insert(0, 0) }
  
  v = []
  32.times { v.insert(0, 1) }
  
  # step D
  k = OpenSSL::HMAC.digest(OpenSSL::Digest.new('sha256'), k.pack("C*"), [].concat(v).concat([0]).concat(x).concat(hash).pack("C*")).bytes.to_a
  
  # step E
  v = OpenSSL::HMAC.digest(OpenSSL::Digest.new('sha256'), k.pack("C*"), v.pack("C*")).bytes.to_a
  
  #  puts "E: " + v.pack("C*").unpack("H*")[0]
  
  # step F
  k = OpenSSL::HMAC.digest(OpenSSL::Digest.new('sha256'), k.pack("C*"), [].concat(v).concat([1]).concat(x).concat(hash).pack("C*")).bytes.to_a
  
  # step G
  v = OpenSSL::HMAC.digest(OpenSSL::Digest.new('sha256'), k.pack("C*"), v.pack("C*")).bytes.to_a
  
  # step H2b (Step H1/H2a ignored)
  v = OpenSSL::HMAC.digest(OpenSSL::Digest.new('sha256'), k.pack("C*"), v.pack("C*")).bytes.to_a
  
  h2b = v.pack("C*").unpack("H*")[0]
  tNum = h2b.to_i(16)
  
  # step H3
  while (!isPositive(tNum) or tNum >= group.order) do
    # k = crypto.HmacSHA256(Buffer.concat([v, new Buffer([0])]), k)
    k = OpenSSL::HMAC.digest(OpenSSL::Digest.new('sha256'), k.pack("C*"), [].concat(v).concat([0]).pack("C*")).bytes.to_a
    
    # v = crypto.HmacSHA256(v, k)
    v = OpenSSL::HMAC.digest(OpenSSL::Digest.new('sha256'), k.pack("C*"), v.pack("C*")).bytes.to_a
    
    # T = BigInteger.fromBuffer(v)
    tNum = v.pack("C*").unpack("H*")[0].to_i(16)
  end
  
  return tNum
end

#isPositive(i) ⇒ Object 



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# File 'lib/block_io.rb', line 231

def isPositive(i)
  sig = "!+-"[i <=> 0]
  
  return sig.eql?("+")
end

#private_key ⇒ Object 



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# File 'lib/block_io.rb', line 176

def private_key
  # returns private key in hex form
  return @private_key.to_s(16)
end

#public_key ⇒ Object 



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# File 'lib/block_io.rb', line 181

def public_key
  # returns the compressed form of the public key to save network fees (shorter scripts)

  return ECDSA::Format::PointOctetString.encode(@public_key, compression: @compressed).unpack("H*")[0]
end

#sign(data) ⇒ Object 



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# File 'lib/block_io.rb', line 187

def sign(data)
  # signed the given hexadecimal string

  nonce = deterministicGenerateK([data].pack("H*"), @private_key) # RFC6979
  
  signature = ECDSA.sign(@group, @private_key, data.to_i(16), nonce)

  # BIP0062 -- use lower S values only
  r, s = signature.components

  over_two = @group.order >> 1 # half of what it was                     
  s = @group.order - s if (s > over_two)

  signature = ECDSA::Signature.new(r, s)

  # DER encode this, and return it in hex form
  return ECDSA::Format::SignatureDerString.encode(signature).unpack("H*")[0]
end