# While using onetime encryption is it possible that one can deduce the key of a message if the contents of the message are already known?

Let's say we have a randomly encrypted message and I pasted the contents of that message on a blog for some reason I do not share the key.

Would you be able to figure out the key?

This is the message not encrypted:

This is the message.


This is the encrypted message:

 -----BEGIN OneTime MESSAGE-----

Version: OneTime 1.122

Offset: 0

QlpoOTFBWSZTWUyTjxYAAAJ+gAgCA4FKYABwSAEoAQAQIAAigA0xMEKBpoZGTEHGQdDBjUXXyo7R
HxdyRThQkEyTjxY=

-----END OneTime MESSAGE-----


The package will not let you use keys twice. Its protocol follows this rule especially for communicating to two computers over telnet, nc, ssh, etc. The protocol can be found here in this link https://www.red-bean.com/onetime/ .

• A quick search shows that OneTime is some kind of Linux package. I'm however not aware of any particular protocol that it adheres to. Do you have any reference to the protocol used? Note that analyzing ciphertext is off topic; we need to have some idea of the protocol used to give a meaningful answer. Without that we'll have to put the question on hold. Jan 29 '19 at 2:33
• I'm not asking to analyze the ciphertext. I'm asking if its possible for an attacker could get the key for some unpractical arbitrary reason just by already knowing the contents of the message. The package will not let you use keys twice. Its protocol follows this rule especially for communicating to two computers over telnet, nc, ssh, etc. The protocol can be found here in this link red-bean.com/onetime Jan 29 '19 at 3:32
• Thanks for the followup and the protocol indication. Exactly what was needed. One minor remark: additional info is best placed in the question. I'll do that for now and then I'll delete these comments tomorrow. Jan 29 '19 at 23:19