im trying to get a call to amazon web service and im stuck on getting the signature, looked at this but i still have a question on it. using this example what is the NSData *keyData; NSData *clearTextData ? what do i need to pass for these two values? /* inputs: NSData *keyData; NSData *clearTextData */ uint8_t digest[CC_SHA1_DIGEST_LENGTH] = {0}; CCHmacContext hmacContext; CCHmacInit(&hmacContext
![iPhone and HMAC-SHA-1 encoding](https://cdn-ak-scissors.b.st-hatena.com/image/square/98d6f053a97a87156775f60757c60865d0f2c47d/height=288;version=1;width=512/https%3A%2F%2Fcdn.sstatic.net%2FSites%2Fstackoverflow%2FImg%2Fapple-touch-icon%402.png%3Fv%3D73d79a89bded)