$data = "1422368544GET/accounts"

$sign = base64_encode(hash_hmac("sha256", $data, base64_decode($this->_secret)));

$headers = array(
          'CB-ACCESS-KEY: '.$this->_key,
          'CB-ACCESS-SIGN: '.$sign,
          'CB-ACCESS-TIMESTAMP: 1422368544',
          'CB-ACCESS-PASSPHRASE: coinigy',
          'Content-Type: application/json'
);