Assange met Leigh to hand him the passphrase, and salt in one meeting, then again to help Leigh unzip the file. Why the hell didn't Assange copy the file across himself using a portable drive, with the file encrypted, then decrypt it himself. If Assange had done that then he would not have had to write the passphrase on a piece of paper, or tell Leigh the salt. Leigh would have gotten his files. The destination computer could have been verified as being offline from the internet. Encryption is only really needed when storing files where others' may have access, or when transfering files, again, where others' may have access, so it would make perfect sense for Assange to dump the encrypted file on say an external drive, copy the file over to Leigh's computer, and decrypt it himself. However, if Assange used the method mentioned above to distribute the same file (with the same encryption) to other journalists then yes, downloading from a server would be the most efficient as Assange wouldn't have to physically meet each of them. But I do suspect he had to in order to give them the passphrase. Whether Assange thought about this as an option (him copying over the encrypted file and decrypting it himself) or not is a mystery, and will probably never be known, but in my experience the safest form of ever transfering encrypted files from A to B is to do it yourself. That way you don't have to