// I am trying to translate the following pseudo code to Apex ->
base64(hmac-sha256({accessKeySecret}, UTF8({stringToSign})))

String dateString = Datetime.now().formatGmt('EEE, dd MMM yyyy HH:mm:ss Z');
String stringtoSign = 'GETnnn'+dateString;string secretAccessKey = '9PK^:WAvBrl1?jz3^U{7+)){igpCG"Y;<.3DGy8gX+' +''' + '6p{|D2#MwI#It8{+@W?>*';
Blob mac = Crypto.generateMac('HMAC-SHA256', blob.valueOf(stringToSign),blob.valueOf(secretAccessKey));
String signature = EncodingUtil.base64Encode(mac);
system.debug(signature);