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<?php
namespace Aws\Signature;
/**
* Provides signature calculation for SignatureV4.
*/
trait SignatureTrait
{
/** @var array Cache of previously signed values */
private $cache = [];
/** @var int Size of the hash cache */
private $cacheSize = 0;
private function createScope($shortDate, $region, $service)
{
return "$shortDate/$region/$service/aws4_request";
}
private function getSigningKey($shortDate, $region, $service, $secretKey)
{
$k = $shortDate . '_' . $region . '_' . $service . '_' . $secretKey;
if (!isset($this->cache[$k])) {
// Clear the cache when it reaches 50 entries
if (++$this->cacheSize > 50) {
$this->cache = [];
$this->cacheSize = 0;
}
$dateKey = hash_hmac(
'sha256',
$shortDate,
"AWS4{$secretKey}",
true
);
$regionKey = hash_hmac('sha256', $region, $dateKey, true);
$serviceKey = hash_hmac('sha256', $service, $regionKey, true);
$this->cache[$k] = hash_hmac(
'sha256',
'aws4_request',
$serviceKey,
true
);
}
return $this->cache[$k];
}
}
|
