in main/src/main/java/org/apache/james/jdkim/tagvalue/SignatureRecordImpl.java [253:263]
public CharSequence getHashAlgo() {
String a = getValue("a").toString();
int pHyphen = a.indexOf('-');
if (pHyphen == -1)
throw new IllegalStateException("Invalid hash method: " + a);
if (a.length() > pHyphen + 3 && a.charAt(pHyphen + 1) == 's'
&& a.charAt(pHyphen + 2) == 'h' && a.charAt(pHyphen + 3) == 'a') {
return "sha-" + a.subSequence(pHyphen + 4, a.length());
} else
return a.subSequence(pHyphen + 1, a.length());
}