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A comment on A JPEG that becomes a PNG after AES encryption and a PDF after 3DES decryption. Parent comment

Re:A JPEG that becomes a PNG after AES encryption and a PDF ... by cbsmith on Friday September 12, 2014 @01:50AM (#8306744)
There is a difference between "symmetric key encryption" and "symmetric encryption".
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Re:A JPEG that becomes a PNG after AES encryption and a PDF ... by dlitz on Friday September 12, 2014 @04:25AM (#8307084)
Is there? The usual term for what you're describing is a "stream cipher" or a "streaming-mode cipher".
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Re:A JPEG that becomes a PNG after AES encryption and a PDF ... by zamalek on Friday September 12, 2014 @05:02AM (#8307183)
I think the objection here comes from not stating that it's AES in CTR mode.

AES is not a symmetric algorithm, AES in CTR mode is.

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Re:A JPEG that becomes a PNG after AES encryption and a PDF ... by cbsmith on Friday September 12, 2014 @06:24AM (#8307352)
The other poster was talking about a stream cipher...

However, I'd point out that DES is a block cipher (thought it can be turned in to streaming cipher much like AES), and its decryption is encryption is with the keys in reverse order. This is how triple-DES can work as it does.

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