NoMethodError: undefined method `group' for <xxxxx>

[mackeee-orange]

Versions:

jwt (2.1.0)
rails (5.1.5)
  actioncable (= 5.1.5)
  actionmailer (= 5.1.5)
  actionpack (= 5.1.5)
  actionview (= 5.1.5)
  activejob (= 5.1.5)
  activemodel (= 5.1.5)
  activerecord (= 5.1.5)
  activesupport (= 5.1.5)
  bundler (>= 1.3.0)
  railties (= 5.1.5)
  sprockets-rails (>= 2.0.0)

I got a error when JWT.encode or JWT.decode with ES256 algorithm.
When I exec them with 'none' algorithm, it spit success.

I show my pry:

[1] pry(main)>     JWT.decode("xxxx.xxxx.xxxx.", "one_pub_key", true, {varify_iat: true, algorithm: 'ES256'})
NoMethodError: undefined method `group' for #<String:0x00007ff408ba7238>
from /Users/mackeee/.rbenv/versions/2.4.2/lib/ruby/gems/2.4.0/gems/jwt2.1.0/lib/jwt/algos/ecdsa.rb:26:in `verify'
[2] pry(main)> payload = {"admin?" => true, "exp" => 182329552, "iat" => 1523295527, "sid" => "hogehoge_mackeee", "tki" => 0, "uid" => "hogehoge"}
=> {"admin?"=>true, "exp"=>182329552, "iat"=>1523295527, "sid"=>"hogehoge_mackeee", "tki"=>0, "uid"=>"hogehoge"}
[3] pry(main)> token = JWT.encode payload, "one_priv_key", 'ES256'
NoMethodError: undefined method `group' for #<String:0x00007ff408a56f50>
from /Users/mackeee/.rbenv/versions/2.4.2/lib/ruby/gems/2.4.0/gems/jwt-2.1.0/lib/jwt/algos/ecdsa.rb:15:in `sign'
[4] pry(main)> token = JWT.encode payload.to_s, "one_priv_key", 'ES256'
NoMethodError: undefined method `group' for #<String:0x00007ff4089ff840>
from /Users/mackeee/.rbenv/versions/2.4.2/lib/ruby/gems/2.4.0/gems/jwt-2.1.0/lib/jwt/algos/ecdsa.rb:15:in `sign'
[5] pry(main)> token = JWT.encode payload, nil, 'none'
=> "yyyy.yyyyy.yyyy."

How can I modify this problem??

[mackeee-orange]

And I use ruby-v2.4.2

[excpt]

Hey @mackeee-orange,

Thanks for the detailed reporting.

Please try to give the JWT.encode and JWT.decode methods the raw key object instead of an string.

Example:

pub_key = OpenSSL::PKey.read(File.read('path_to_my_pub_key.pem'))

JWT.decode(payload, pub_key, true, my_options)

[mackeee-orange]

@excpt Thank you for comment.

Sorry, there is misunderstanding.
I don't have a PEM nor RSA, but only the hex string "04xxx...yyy..." representing the public key.

[ab320012]

@mackeee-orange you can generate a public key object from the string in the following way...

# substitute public_key_octet_string with your string
ec = OpenSSL::PKey::EC.new('prime256v1')
key_bn = OpenSSL::BN.new(public_key_octet_string, 2)  # 2 means binary
ec.public_key = OpenSSL::PKey::EC::Point.new(ec.group, key_bn)
#ec.public_key can be passed to JWT.decode

source:
https://stackoverflow.com/questions/22293864/ruby-openssl-convert-elliptic-curve-point-octet-string-into-opensslpkeyec?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa

[mackeee-orange]

thank you @ab320012
I got it by refer your code

hex_string = "04xxxxx.....yyyyy......"
ec = OpenSSL::PKey::EC.new('prime256v1')
key_bn = OpenSSL::BN.new(hex_string, 16)
ec.public_key = OpenSSL::PKey::EC::Point.new(ec.group, key_bn)
JWT.decode @bearer_token, ec, true, { algorithm: 'ES256' }