None of the major cryptographic hashes (MD5, SHA-*) have practical preimage attacks. It means pulling off what the author suggests (having a document hash to an

None of the major cryptographic hashes (MD5, SHA-*) have practical preimage attacks. It means pulling off what the author suggests (having a document hash to an illegal number) is impossible in practice, at least for now. It could be possible using a non-cryptographic hash (murmurhash, CRC,...).