azure-storage-common/src/Common/Internal/Authentication/SharedKeyAuthScheme.php
public function getAuthorizationHeader(
        array $headers,
        $url,
        array $queryParams,
        $httpMethod
    ) {
        $signature = $this->computeSignature(
            $headers,
            $url,
            $queryParams,
            $httpMethod
        );

        return 'SharedKey ' . $this->accountName . ':' . base64_encode(
            hash_hmac('sha256', $signature, base64_decode($this->accountKey), true)
        );
    }
public function getAuthorizationHeader(
        array $headers,
        $url,
        array $queryParams,
        $httpMethod
    ) {
        $signature = $this->computeSignature(
            $headers,
            $url,
            $queryParams,
            $httpMethod
        );

        return 'SharedKey ' . $this->accountName . ':' . base64_encode(
            hash_hmac('sha256', $signature, base64_decode($this->accountKey), true)
        );
    }
Returns authorization header to be included in the request.

@param array  $headers     request headers.
@param string $url         reuqest url.
@param array  $queryParams query variables.
@param string $httpMethod  request http method.

@see Specifying the Authorization Header section at
http://msdn.microsoft.com/en-us/library/windowsazure/dd179428.aspx

@return string