in src/main/java/com/amazonaws/codepipeline/jenkinsplugin/Validation.java [117:122]
private static boolean credentialsAreValid(final String awsAccessKey, final String awsSecretKey) {
return awsAccessKey != null
&& awsSecretKey != null
&& ((awsAccessKey.isEmpty() && awsSecretKey.isEmpty())
|| (!awsAccessKey.isEmpty() && !awsSecretKey.isEmpty()));
}