network profile
| bio | website | bramcohen.com |
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| location | ||
| age | ||
| visits | member for | 5 months |
| seen | Mar 18 at 23:28 | |
| stats | profile views | 1 |
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Jan 20 |
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Is a steganographic technique which has a universal decoder novel/secure? @Mok-KongShen Given that there's auto-complete, you could at least spell my name right. Your last comment prompted me to remember that you're Mok-Kong "Poor Man's Encryption" Shen, so I won't be making any further efforts to win your approval. |
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Jan 18 |
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Is a steganographic technique which has a universal decoder novel/secure? @Mok-KongShen The universal decoder feature does, in fact, demonstrably work, so I'm not sure what your skepticism of it can possibly mean. You emailstegano scheme can be easily reimplemented with my tool, and I think I'll go ahead and do that for illustration purposes. |
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Jan 18 |
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Is a steganographic technique which has a universal decoder novel/secure? @Mok-KongShen Yes this is a framework for allowing 'native' encodings to be built. It brings with it some features which to date I don't believe have been in any stego system: It has a universal decoder, which is never changed regardless of iteration on encoding, and it allows multiple messages to be encoded to multiple keys without even people with those keys being able to determine whether the other messages are in there. It also allows for much simpler development of stego encoding schemes. As for the correlation of bits, there simply isn't one. All bits of the covertext go into the message |
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Jan 18 |
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Is a steganographic technique which has a universal decoder novel/secure? @mhum Improving the state of the art in crypto libraries is beyond the scope of this project. |
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Jan 17 |
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Is a steganographic technique which has a universal decoder novel/secure? @mhum These are not obscure tools, nor are the libraries hard to install. |
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Jan 17 |
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Is a steganographic technique which has a universal decoder novel/secure? @Mok-KongShen In the case of the line endings encoder after encoding is done half the lines (basically randomly picked) will have trailing spaces. In the case of the tab encoder half the lines (again essentially randomly) will have their leading spaces be tabs. These are meant to be simple illustrations of the flexibility of the system, not hard to detect stego schemes themselves. |
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Jan 17 |
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Is a steganographic technique which has a universal decoder novel/secure? @Mok-KongShen There are instructions right there in the readme about how to use the two encoders which are included. They're simple command line tools which use source code files as covertext. |
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Jan 17 |
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Is a steganographic technique which has a universal decoder novel/secure? @Mok-KongShen You're missing the point. There is no single place in the file where the bits are hidden. Every bit of the covertext affects every bit of the hidden text. |
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Jan 16 |
awarded | Commentator |
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Jan 16 |
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Is a steganographic technique which has a universal decoder novel/secure? argh, well apparently it's impossible to format python code in comments properly here. Anyhow it's the partial_decode_message() method of this file: github.com/bramcohen/DissidentX/blob/master/… |
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Jan 16 |
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Is a steganographic technique which has a universal decoder novel/secure? The essential part of the reconstruction step is in this function, which should be completely unambiguous (x() is a bytewise xor function): def partial_decode_message(key, message, mylen): r = bytes([0] * mylen) for i in range(len(message) - 15): r = x(r, encrypt_ofb(key, message[i:i+16], bytes([0] * mylen))) return r |
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Jan 16 |
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Is a steganographic technique which has a universal decoder novel/secure? The input is a processed covertext with possible alternates and a message to encode and a key. By 'processed', I mean there are places specified in the covertext which can be replaced with an alternative value. The return value is a covertext with some of the alternates flipped and some of them left as normal. To get back the message you have to run recovery on the whole covertext and the key. Instead of the usual business of individual parts of the covertext corresponding to bits of the output, the entire covertext corresponds to the entire output. |
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Jan 16 |
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Is a steganographic technique which has a universal decoder novel/secure? If you were familiar with modern steganography you'd know that using keys and having the message be encrypted with those keys before being hidden is standard practice these days. |
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Jan 16 |
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Is a steganographic technique which has a universal decoder novel/secure? Do you actually know anything about steganography beyond the catchphrase 'steganography is security through obscurity'? That statement makes about as much sense as saying 'encryption is security through obscurity', although it seems to be popular for some reason, not sure where everybody gets it from. |
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Jan 16 |
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Is a steganographic technique which has a universal decoder novel/secure? The 'math' part of the whole thing is explained right there in my question, it's the part about row reduction. |
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Jan 16 |
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Is a steganographic technique which has a universal decoder novel/secure? Yes, I'm saying 'plaintext' in places where I really should be saying 'covertext'. As for what 'alternate' means, the covertext has to be transformed into alternating fixed strings and pairs of fixed strings. The pairs can be things like "" and " " or "is not" and "isn't" or "color" and "colour" or, well, you get the idea, any two strings will do. Each of those is what I mean by an 'alternate'. The output of doing the encoding will be filling in exactly one of the values from each alternate. |
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Jan 15 |
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Is a steganographic technique which has a universal decoder novel/secure? "If you want to use a strong encryption algorithm to encrypt the message first, before the steganograpic step, then I don't see why you would add the latter. It doesn't add extra security." - It's so you can send data down a plaintext channel where obviously encrypted messages are filtered out or deemed suspicious. |
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Jan 15 |
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Is a steganographic technique which has a universal decoder novel/secure? The basic API involves feeding in a key and a message to be hidden and a preprocessed message to hide that message in with alternate values in places - for example, having a trailing space at the end of each line of a source code file or not. Any alternates will do though, including multiple techniques for generating alternates in the same file, which is the whole point of the approach. |
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Jan 15 |
revised |
Is a steganographic technique which has a universal decoder novel/secure? edited tags |
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Jan 15 |
awarded | Student |
