crypto_gost3410

== CryptoGost3410

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

=== Installation

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

=== Usage

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_size2)<=ukm<2**(coord_size8)

ukm = SecureRandom.random_number(2**(coord_size2)..2**(coord_size8)-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)}"

=== Converting GOST digest, public_key and signature strings to big numbers and vise versa

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)

=== List of TC 26 GOST 34.10-2012 elliptic curves:

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)

=== Testing

Run spec test from crypto_gost3410 source project directory:

$ bundle exec rake spec

=== Thanks

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

=== Contributing

Bug reports and pull requests are welcome on GitHub at https://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 code of conduct.

=== License

The gem is available as open source under the terms of the MIT License.