Method: Oydid.decode_private_key

Defined in:

lib/oydid/basic.rb

.decode_private_key(key_encoded, options = {}) ⇒ Object

# File 'lib/oydid/basic.rb', line 802

def self.decode_private_key(key_encoded, options = {})
    code, length, digest = multi_decode(key_encoded).first.unpack('SCa*')
    case Multicodecs[code].name
    when 'ed25519-priv'
        private_key = Ed25519::SigningKey.new(digest).to_bytes
    when 'p256-priv'
        group = OpenSSL::PKey::EC::Group.new('prime256v1')
        pub_key = group.generator.mul(OpenSSL::BN.new(digest, 2))
        pub_oct = pub_key.to_bn.to_s(2)

        parameters = OpenSSL::ASN1::ObjectId("prime256v1")
        parameters.tag = 0
        parameters.tagging = :EXPLICIT
        parameters.tag_class = :CONTEXT_SPECIFIC

        public_key_bitstring = OpenSSL::ASN1::BitString(pub_oct)
        public_key_bitstring.tag = 1
        public_key_bitstring.tagging = :EXPLICIT
        public_key_bitstring.tag_class = :CONTEXT_SPECIFIC

        ec_private_key_asn1 = OpenSSL::ASN1::Sequence([
            OpenSSL::ASN1::Integer(1),
            OpenSSL::ASN1::OctetString(digest),
            parameters,
            public_key_bitstring
        ])
        private_key = OpenSSL::PKey.read(ec_private_key_asn1.to_der)

    else
        return [nil, "unsupported key codec"]
    end
    return [private_key, nil]

end