Ruby library implementing GOST 34.10-2012 ECC signature and VKO algorithms. Forked from github.com/wilddima/crypto_gost.

Add this line to your application’s Gemfile:

gem 'crypto_gost3410'

And then execute:

$ bundle

Or install it yourself as:

$ gem install crypto_gost3410

Or install it locally from source crypto_gost3410 project directory

$ bundle exec rake install

# All input and output data for CryptoGost3410 are big numbers only, not byte arrays nor strings.
# As so, input CryptoGost3411 message digest should be converted to big number too.
# We removed SecureRandom random number generations out of module to use any external generator.
# In version 0.2.1 tests we use crypto_gost3411 gem instead of stribog gem for digest generation.

require 'securerandom'
require 'crypto_gost3411'
require 'crypto_gost3410'

group = CryptoGost3410::Group::Gost256tc26a
puts group.opts[:name]
puts group.opts[:id]
puts group.opts[:oid]

coord_size = group.opts[:coord_size] # in bytes

generator = CryptoGost3410::Generator.new(group)  # for sign and for vko
verifier = CryptoGost3410::Verifier.new(group)    # for verify

# private_key is random number 0<n<group.order
# you can use fixed number for debugging
private_key = SecureRandom.random_number(1..group.order-1) 
puts "private_key: #{private_key.to_s(16)}"

public_key = group.generate_public_key private_key
puts "public_key.x: #{public_key.x.to_s(16)}"
puts "public_key.y: #{public_key.y.to_s(16)}"

# Signature:

message = 'ruby'
digest = CryptoGost3411::Gost3411.new(coord_size).update(message).final
CryptoGost3410::Converter.printBytes(digest, coord_size * 2)   
digest_num = CryptoGost3410::Converter.bytesToBignum(digest.reverse)
puts "digest_num: #{digest_num.to_s(16)}"

# rnd_val is random number 0<n<group.order so as private_key
# you can use fixed number for debugging
rand_val = SecureRandom.random_number(1..group.order-1)
puts "rand_val: #{rand_val.to_s(16)}"

signature = generator.sign(digest_num, private_key, rand_val)
puts "signature.x: #{signature.x.to_s(16)}"   # x stands for r
puts "signature.y: #{signature.y.to_s(16)}"   # y stands for s

signature_ok = verifier.verify(digest_num, public_key, signature)
puts "signature_ok: #{signature_ok}"

# VKO:

receiver_private_key = SecureRandom.random_number(1..group.order-1) 
puts "receiver_private_key: #{receiver_private_key.to_s(16)}"

receiver_public_key = group.generate_public_key receiver_private_key
puts "receiver_public_key.x: #{receiver_public_key.x.to_s(16)}"
puts "receiver_public_key.y: #{receiver_public_key.y.to_s(16)}"

# ukm is random number 2**(coord_size*2)<=ukm<2**(coord_size*8)
ukm = SecureRandom.random_number(2**(coord_size*2)..2**(coord_size*8)-1)
puts "ukm: #{ukm.to_s(16)}"

sender_vko = generator.vko(ukm, private_key, receiver_public_key)
puts "sender_vko.x: #{sender_vko.x.to_s(16)}"
puts "sender_vko.y: #{sender_vko.y.to_s(16)}"

receiver_vko = generator.vko(ukm, receiver_private_key, public_key)
puts "receiver_vko.x: #{receiver_vko.x.to_s(16)}"
puts "receiver_vko.y: #{receiver_vko.y.to_s(16)}"

puts "vko_ok: #{(sender_vko.x == receiver_vko.x) && (sender_vko.y == receiver_vko.y)}"

require 'crypto_gost3411'
require 'crypto_gost3410'

group = CryptoGost3410::Group::Gost256tc26test
coord_size = group.opts[:coord_size] # in bytes

# get tbs, signer public_key and signature byte strings from x509 certificate
# ...
# generate digest
digest32 = CryptoGost3411::Gost3411.new(coord_size).update(tbs).final
# little-endian digest32 -> reverse -> big-endian -> BigNum
digest32_num = CryptoGost3410::Converter.bytesToBignum(digest32.reverse)
# public key x||y little-endian -> reverse -> big-endian -> Point(x_num, y_num)
public_key_x_num = CryptoGost3410::Converter.bytesToBignum(public_key[0...coord_size].reverse)
public_key_y_num = CryptoGost3410::Converter.bytesToBignum(public_key[coord_size..-1].reverse)
public_key_point = CryptoGost3410::Point.new(group, [public_key_x_num, public_key_y_num])
# signature s||r big-endian -> Point(r_num, s_num)
signature_s_num = CryptoGost3410::Converter.bytesToBignum(signature[0...coord_size])
signature_r_num = CryptoGost3410::Converter.bytesToBignum(signature[coord_size..-1])
signature_point = CryptoGost3410::Point.new(group, [sig_r_num, sig_s_num]) 

signature_point_ok = CryptoGost3410::Verifier.new(group).verify(digest32_num, public_key_point, signature_point)
puts "signature_point_ok: #{signature_point_ok}"

# Converting signature point to byte string ( s||r, big-endian):
signature_bytes_s = CryptoGost3410::Converter.bignumToBytes(signature_point.x, coord_size)
signature_bytes_r = CryptoGost3410::Converter.bignumToBytes(signature_point.y, coord_size)
signature_bytes = signature_bytes_s + signature_bytes_r
# Print signature bytes in hex (64 symbols in line)
CryptoGost3410::Converter.printBytes(signature_bytes, coord_size * 2)

Gost256tc26test - id-tc26-gost-3410-2012-256-paramSetTest (former id-GostR3410-2001-TestParamSet). Use for testing only!
Gost256tc26a    - id-tc26-gost-3410-2012-256-paramSetA (Edwards twisted curve)
Gost256tc26b    - id-tc26-gost-3410-2012-256-paramSetB (former id-GostR3410-2001-CryptoPro-A-ParamSet)
Gost256tc26c    - id-tc26-gost-3410-2012-256-paramSetC (former id-GostR3410-2001-CryptoPro-B-ParamSet)
Gost256tc26d    - id-tc26-gost-3410-2012-256-paramSetD (former id-GostR3410-2001-CryptoPro-C-ParamSet)
Gost512test     - id-tc26-gost-3410-2012-512-paramSetTest. Use for testing only!
Gost512tc26a    - id-tc26-gost-3410-2012-512-paramSetA
Gost512tc26b    - id-tc26-gost-3410-2012-512-paramSetB
Gost512tc26c    - id-tc26-gost-3410-2012-512-paramSetC (Edwards twisted curve)

You can find group by name, by id, by oid and by der_oid:

name = 'Gost256tc26test'
group = CryptoGost3410::Group.findByName(name)

id = 'id-tc26-gost-3410-2012-256-paramSetTest'
group = CryptoGost3410::Group.findById(id)

oid = '1.2.643.7.1.2.1.1.0'
group = CryptoGost3410::Group.findByOid(oid)

der_oid = "\x06\x09\x2a\x85\x03\x07\x01\x02\x01\x01\x00"
group = CryptoGost3410::Group.findByDerOid(der_oid)

Run spec test from crypto_gost3410 source project directory:

$ bundle exec rake spec

Thanks to WildDima for root crypto_gost project on GitHub at github.com/wilddima/crypto_gost.

Bug reports and pull requests are welcome on GitHub at github.com/vblazhnovgit/crypto_gost3410. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](contributor-covenant.org) code of conduct.

The gem is available as open source under the terms of the [MIT License](opensource.org/licenses/MIT).