Project

cose

0.51
Low commit activity in last 3 years
No release in over a year
Ruby implementation of RFC 8152 CBOR Object Signing and Encryption (COSE)
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
 Dependencies

Development

~> 2.2.0
>= 1.17, < 3
~> 11.0
~> 13.0
~> 3.8
= 0.80.1

Runtime

 Project Readme

cose-ruby

Ruby implementation of RFC 8152 CBOR Object Signing and Encryption (COSE)

Gem Actions Build

Installation

Add this line to your application's Gemfile:

gem 'cose'

And then execute:

$ bundle

Or install it yourself as:

$ gem install cose

Usage

Key Objects

Deserialization (from CBOR to Ruby objects)

cbor_data = "..."

key = COSE::Key.deserialize(cbor_data)

Once you have a COSE::Key instance you can either access key parameters directly and/or convert it to an OpenSSL::PKey::PKey instance (if supported for the key type) for operating with it (encrypting/decrypting, signing/verifying, etc).

# Convert to an OpenSSL::PKey::PKey
if key.respond_to?(:to_pkey)
  openssl_pkey = key.to_pkey
end

# Access COSE key parameters
case key
when COSE::Key::OKP
  key.crv
  key.x
  key.d
when COSE::Key::EC2
  key.crv
  key.x
  key.y
  key.d
when COSE::Key::RSA
  key.n
  key.e
  key.d
  key.p
  key.q
  key.dp
  key.dq
  key.qinv
when COSE::Key::Symmetric
  key.k
end

If you already know which COSE key type is encoded in the CBOR data, then:

okp_key_cbor = "..."

cose_okp_key = COSE::Key::OKP.deserialize(okp_key_cbor)

cose_okp_key.crv
cose_okp_key.x
cose_okp_key.d
ec2_key_cbor = "..."

cose_ec2_key = COSE::Key::EC2.deserialize(ec2_key_cbor)

cose_ec2_key.crv
cose_ec2_key.x
cose_ec2_key.y
cose_ec2_key.d

# or

ec_pkey = cose_ec2_key.to_pkey # Instance of an OpenSSL::PKey::EC
symmetric_key_cbor = "..."

cose_symmetric_key = COSE::Key::Symmetric.deserialize(symmetric_key_cbor)

cose_symmetric_key.k
rsa_key_cbor = "..."

cose_rsa_key = COSE::Key::RSA.deserialize(rsa_key_cbor)

cose_rsa_key.n
cose_rsa_key.e
cose_rsa_key.d
cose_rsa_key.p
cose_rsa_key.q
cose_rsa_key.dp
cose_rsa_key.dq
cose_rsa_key.qinv

# or

rsa_pkey = cose_rsa_key.to_pkey # Instance of an OpenSSL::PKey::RSA

Serialization (from Ruby objects to CBOR)

ec_pkey = OpenSSL::PKey::EC.new("prime256v1").generate_key

cose_ec2_key_cbor = COSE::Key.serialize(ec_pkey)
rsa_pkey = OpenSSL::PKey::RSA.new(2048)

cose_rsa_key_cbor = COSE::Key.serialize(rsa_pkey)

Signing Objects

COSE_Sign

cbor_data = "..."

sign = COSE::Sign.deserialize(cbor_data)

# Verify by doing (key should be a COSE::Key):
sign.verify(key)

# or, if externally supplied authenticated data exists:
sign.verify(key, external_aad)

# Then access payload
sign.payload

COSE_Sign1

cbor_data = "..."

sign1 = COSE::Sign1.deserialize(cbor_data)

# Verify by doing (key should be a COSE::Key):
sign1.verify(key)

# or, if externally supplied authenticated data exists:
sign1.verify(key, external_aad)

# Then access payload
sign1.payload

MAC Objects

COSE_Mac

cbor_data = "..."

mac = COSE::Mac.deserialize(cbor_data)

# Verify by doing (key should be a COSE::Key::Symmetric):
mac.verify(key)

# or, if externally supplied authenticated data exists:
mac.verify(key, external_aad)

# Then access payload
mac.payload

COSE_Mac0

cbor_data = "..."

mac0 = COSE::Mac0.deserialize(cbor_data)

# Verify by doing (key should be a COSE::Key::Symmetric):
mac0.verify(key)

# or, if externally supplied authenticated data exists:
mac0.verify(key, external_aad)

# Then access payload
mac0.payload

Encryption Objects

COSE_Encrypt

cbor_data = "..."

encrypt = COSE::Encrypt.deserialize(cbor_data)

encrypt.protected_headers
encrypt.unprotected_headers
encrypt.ciphertext

encrypt.recipients.each do |recipient|
  recipient.protected_headers
  recipient.unprotected_headers
  recipient.ciphertext

  if recipient.recipients
    recipient.recipients.each do |recipient|
      recipient.protected_headers
      recipient.unprotected_headers
      recipient.ciphertext
    end
  end
end

COSE_Encrypt0

cbor_data = "..."

encrypt0 = COSE::Encrypt0.deserialize(cbor_data)

encrypt0.protected_headers
encrypt0.unprotected_headers
encrypt0.ciphertext

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/cedarcode/cose-ruby.

License

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