public byte[] hash(String text) throws SdkClientException {
        return AbstractAWSSigner.doHash(text);
    }
Hashes the string contents (assumed to be UTF-8) using the SHA-256
algorithm.

@param text
           The string to hash.

@return The hashed bytes from the specified string.

@throws SdkClientException
            If the hash cannot be computed.
aws-java-sdk-core/src/main/java/com/amazonaws/auth/AbstractAWSSigner.java