signature := calculateSignatureV2(stringToSign, cred.SecretKey)
	return signature
}

// compareSignatureV2 returns true if and only if both signatures
// are equal. The signatures are expected to be base64 encoded strings
// according to the AWS S3 signature V2 spec.
func compareSignatureV2(sig1, sig2 string) bool {
	// Decode signature string to binary byte-sequence representation is required