library/Garp/Mail/Transport/AmazonSes.php
private function _buildAuthKey($date){
        return sprintf('AWS3-HTTPS AWSAccessKeyId=%s,Algorithm=HmacSHA256,Signature=%s', $this->_accessKey, base64_encode(hash_hmac('sha256', $date, $this->_privateKey, TRUE)));
    }
private function _buildAuthKey($date){
        return sprintf('AWS3-HTTPS AWSAccessKeyId=%s,Algorithm=HmacSHA256,Signature=%s', $this->_accessKey, base64_encode(hash_hmac('sha256', $date, $this->_privateKey, TRUE)));
    }
private function _buildAuthKey ( $ date ) { return sprintf ( 'AWS3-HTTPS AWSAccessKeyId=%s,Algorithm=HmacSHA256,Signature=%s' , $ this -> _accessKey , base64_encode ( hash_hmac ( 'sha256' , $ date , $ this -> _privateKey , TRUE ) ) ) ; }
Returns header string containing encoded authentication key

@param   date $date
@return  string
Returns header string containing encoded authentication key