pkeys are immutable on OpenSSL 3.0\e[0m (OpenSSL::PKey::PKeyError)

HI, how do I use the existing private key and public key to encrypt the message? The keys are immutable now.

Fastfile:821:in `private_key=': \e[31m[!] pkeys are immutable on OpenSSL 3.0\e[0m (OpenSSL::PKey::PKeyError)

Environment:

ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [arm64-darwin21]
openssl (3.1.0, default: 2.2.0)
fastlane | 2.212.2 | ✅ Up-To-Date

Sample Code:

def get_force_update_message
    message = "message"
    private_key = "sample_private_key"
    public_key = "sample_public_key"

    # encrypt
    group = OpenSSL::PKey::EC::Group.new('secp256k1')
    key = OpenSSL::PKey::EC.new(group)
    key.private_key = OpenSSL::BN.new(private_key, 16)

    signature = key.dsa_sign_asn1(message)
    signature_base64 = Base64.encode64(signature).gsub("\n", "")

    # verify
    public_key_bn = OpenSSL::BN.new(public_key, 16)
    key.public_key = OpenSSL::PKey::EC::Point.new(group, public_key_bn)
    key.dsa_verify_asn1(message, signature)

    return "#{message}&#{signature_base64}"
  end

Error:

[17:13:51]: Error in your Fastfile at line 821
[17:13:51]:     819:	    group = OpenSSL::PKey::EC::Group.new('secp256k1')
[17:13:51]:     820:	    key = OpenSSL::PKey::EC.new(group)
[17:13:51]:  => 821:	    key.private_key = OpenSSL::BN.new(private_key, 16)
[17:13:51]:     822:	
[17:13:51]:     823:	    signature = key.dsa_sign_asn1(message)
[17:13:51]: pkeys are immutable on OpenSSL 3.0

+------+----------------------+-------------+
|             fastlane summary              |
+------+----------------------+-------------+
| Step | Action               | Time (in s) |
+------+----------------------+-------------+
| 1    | default_platform     | 0           |
| 2    | xcodes               | 0           |
| 3    | ensure_env_vars      | 0           |
| 4    | set_info_plist_value | 0           |
| 5    | ensure_env_vars      | 0           |
+------+----------------------+-------------+

[17:13:51]: fastlane finished with errors

Looking for related GitHub issues on fastlane/fastlane...

Found no similar issues. To create a new issue, please visit:
https://github.com/fastlane/fastlane/issues/new
Run `fastlane env` to append the fastlane environment to your issue
Fastfile:821:in `private_key=': \e[31m[!] pkeys are immutable on OpenSSL 3.0\e[0m (OpenSSL::PKey::PKeyError)
	from Fastfile:821:in `get_force_update_message'
	from Fastfile:252:in `block (2 levels) in parsing_binding'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/fastlane-2.212.2/fastlane/lib/fastlane/lane.rb:33:in `call'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/fastlane-2.212.2/fastlane/lib/fastlane/runner.rb:49:in `block in execute'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/fastlane-2.212.2/fastlane/lib/fastlane/runner.rb:45:in `chdir'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/fastlane-2.212.2/fastlane/lib/fastlane/runner.rb:45:in `execute'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/fastlane-2.212.2/fastlane/lib/fastlane/lane_manager.rb:47:in `cruise_lane'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/fastlane-2.212.2/fastlane/lib/fastlane/command_line_handler.rb:36:in `handle'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/fastlane-2.212.2/fastlane/lib/fastlane/commands_generator.rb:110:in `block (2 levels) in run'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/commander-4.6.0/lib/commander/command.rb:187:in `call'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/commander-4.6.0/lib/commander/command.rb:157:in `run'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/commander-4.6.0/lib/commander/runner.rb:444:in `run_active_command'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/fastlane-2.212.2/fastlane_core/lib/fastlane_core/ui/fastlane_runner.rb:124:in `run!'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/commander-4.6.0/lib/commander/delegates.rb:18:in `run!'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/fastlane-2.212.2/fastlane/lib/fastlane/commands_generator.rb:354:in `run'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/fastlane-2.212.2/fastlane/lib/fastlane/commands_generator.rb:43:in `start'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/fastlane-2.212.2/fastlane/lib/fastlane/cli_tools_distributor.rb:123:in `take_off'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/gems/fastlane-2.212.2/bin/fastlane:23:in `<top (required)>'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/bin/fastlane:25:in `load'
	from /opt/homebrew/Cellar/fastlane/2.212.2/libexec/bin/fastlane:25:in `<main>'

Start with the sample in Fastfile:821 and reproduce the failure at OpenSSL::PKey::EC#private_key= using Ruby 3.0 and OpenSSL 3.1. Read the OpenSSL::PKey::EC key-construction and signing APIs to determine the supported way to use the supplied private and public key values. Done means the reported signing and verification flow no longer raises the immutability error, with coverage for the OpenSSL 3 behavior.