A system for generating a security document includes a plurality of computing nodes forming a computing cluster, each computing node having a node identifier for uniquely identifying the node within the cluster, each node being capable of running multiple concurrent processes, and each process having a process identifier for uniquely identifying the process within the node, at least some of the processes on at least some of the nodes being adapted to perform the steps of: a. collecting information for inclusion in the document, the information including at least a subject identifier for uniquely identifying a subject of the document; b. generating a first random value and a second random value; c. concatenating the subject identifier and the second random value; d. applying a cryptographic hash function to the concatenation of the subject identifier and the second random value, resulting in a message digest value; e. truncating the message digest value; f. generating a document identifier comprising a concatenation of the node identifier, a first delimiter, the process identifier, the first delimiter, the first random value, a second delimiter, and the truncated message digest value; g. generating the security document, and applying the document identifier visibly to the document; and h. storing the document and the document identifier in a database, the document being retrievable from the database by means of the document identifier.