Decrypt PKCS#8 Ruby OpenSSL - ruby-on-rails

Question

I need to use the OpenSSL ruby gem to decrypt a file. I've tried what every post told me to do. I've tried using this code from: Load PKCS#8 binary key into Ruby
def box(tag, lines)
lines.unshift "-----BEGIN #{tag}-----"
lines.push "-----END #{tag}-----"
lines.join("\n")
end
def der_to_pem(tag, der)
box tag, Base64.strict_encode64(der).scan(/.{1,64}/)
end
pem = der_to_pementer code here('ENCRYPTED PRIVATE KEY', File.read('./file.key'))
key = OpenSSL::PKey::RSA.new(pem, 'passkey')
puts key
puts pem
And I get this:
-----BEGIN RSA PRIVATE KEY-----
MIIEpQIBAAKCAQEAzxy...
...ECYUOVC3zgw23aGcFA8z9ghI=
-----END RSA PRIVATE KEY-----
-----BEGIN ENCRYPTED PRIVATE KEY-----
MIIFDjBABgk...
...Y948X9Zop7aCnxmWI7vHNts=
-----END ENCRYPTED PRIVATE KEY-----
But I need something like this:
-----BEGIN PRIVATE KEY-----
MIIEvwIBADA...
...ZwUDzP2CEg==
-----END PRIVATE KEY-----
This is the console code that works, but as I said I need to use the ruby gem:
openssl pkcs8 -inform DER -in "./file.key" -passin pass:passkey -out "./file.key.pem"

Answer 1

Unfortunately, there is no way to decrypt on PKCS#8 format by openssl gem. But there are some hacky ways.
Execute the OpenSSL command from ruby.
Install the following gem (https://github.com/twg/openssl_pkcs8)