def decrypt(field)
      return if field !~ /\S/
      iv, encrypted_aes_key, encrypted_text = parse(field)
      private_key = OpenSSL::PKey::RSA.new(File.read(private_key_filepath))
      decrypted_aes_key = private_key.private_decrypt(Base64.decode64(encrypted_aes_key))
      decrypted_field = decrypt_data(iv, decrypted_aes_key, encrypted_text)
      decrypted_field.force_encoding(encoding)
    end
def decrypt(field)
      return if field !~ /\S/
      iv, encrypted_aes_key, encrypted_text = parse(field)
      private_key = OpenSSL::PKey::RSA.new(File.read(private_key_filepath))
      decrypted_aes_key = private_key.private_decrypt(Base64.decode64(encrypted_aes_key))
      decrypted_field = decrypt_data(iv, decrypted_aes_key, encrypted_text)
      decrypted_field.force_encoding(encoding)
    end
Decrypt the provided cipher text, and return the plaintext
 Return nil if whitespace