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I need to send large files from a Linux machine to another using cryptography. The sender machine knows the recipient IP but not vice-versa. I don't need strong cryptography and prefer higher-speed less-secure solutions.

There are no problems with presharing crypto keys but I'd prefer not dealing with SSH users creation.

I think to HTTP PUT over TLS, but I never had experience with it and I prefer to hear which are the possible solutions.

Ah, I need some kind of authentication to avoid abuse.

What about rsync? I know that it can listen as a daemon but I don't know anything about cryptography. So pipeing with OpenSSL may be a solution.

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The receiver can always know the senders IP address, unless you use a proxy server. – Keith Aug 28 '11 at 20:00
Please elaborate on why you cannot use SSH. That is the canonical solution. – Keith Aug 28 '11 at 20:02
@Keith Yeah, I know that, simply I don't want to store the sender IP on the receiver, so that if the transfers stop there is no way to get to the sender from the receiver. – FiloSottile Aug 28 '11 at 20:11
@Keith I want to avoid SSH both because of its heavy log traces and because it gives a too wide access to the machine. I know that I can restrict the use of a specific key, but it remains an overkill. I prefer so a specific service than something wide, heavy and system-user related like SSH. – FiloSottile Aug 28 '11 at 20:17
Actually, the ssh server is very configurable. See man sshd_config for more information. – Keith Aug 29 '11 at 0:08
up vote 0 down vote accepted

How about just sending an encrypted Zip file? Its uses AES-256 encryption and you can send it via a copy/ftp/whatever.

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That's similar to using some OpenSSL on the two sides but what interests me most is the transfer way. Setting up an FTP server seems a great idea, but what do you mean for "copy"? – FiloSottile Aug 28 '11 at 20:20
Just a generic term. Since the file itself is encrypted, you could use any method for transfer. You said security wasnt a priority... – Keltari Aug 28 '11 at 20:22
Yeah, exact. Now I am looking with interest to FTPS (not SFTP) – FiloSottile Aug 28 '11 at 20:25
Went with FTPS, thanks all – FiloSottile Aug 29 '11 at 19:19

Have a look at SCP (Secure Copy).

It is a fairly standard method of securely copying files from one machine to another.

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No, it is SSH based. If I can avoid it I want to, said above. Too much logs and system users stuff. – FiloSottile Aug 28 '11 at 19:33
I'm not at all convinced by your objections to SSH. As Keith said in comments on the question, you can configure it pretty much however you want, e.g. disabling all logging and only accepting connections for a single unprivileged user. – David Z Aug 29 '11 at 19:18

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