in main/src/main/java/org/apache/james/jdkim/tagvalue/SignatureRecordImpl.java [281:289]
public void setBodyHash(byte[] newBodyHash) {
String bodyHash = new String(Base64.encodeBase64(newBodyHash));
setValue("bh", bodyHash);
// If a t=; parameter is present in the signature, make sure to
// fill it with the current timestamp
if (getValue("t") != null && getValue("t").toString().trim().isEmpty()) {
setValue("t", "" + (System.currentTimeMillis() / 1000));
}
}