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enter image description here

Based on this, it looks like something slightly wrong. What would need to be adjusted at the transmitter side to allow the receiver to decrypt the message/data?

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closed as unclear what you're asking by Ella Rose, e-sushi Aug 16 '18 at 22:32

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    $\begingroup$ A better question might be: "I don't understand this because ..." instead of something is wrong. What part do you not understand? $\endgroup$ – zaph Aug 14 '18 at 21:06
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There is nothing wrong. This is 3DES with two keys.

The Decryption operation precisely undoes the Encryption operation.

The right E in Encryption is undone by the left D in Decryption, the middle D in Encryption is undone by the middle E in Decryption, the left E in Encryption is undone by the right D in Decryption.

For a rigorous proof that using D in the encryption still allows decryption, see this. For an explanation of why the D in the encryption, see this. These are for 3DES with 3 keys, but the reasoning applies to 2 keys as well.

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  • $\begingroup$ The answer might be better if why EDE/DED was chosen and not EEE/DDD. The D in encrypt and E in decrypt might be what the OP is concerned about. $\endgroup$ – zaph Aug 14 '18 at 23:30
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    $\begingroup$ @zaph: if so they could look at crypto.stackexchange.com/questions/2060/… (and several others linked to it) $\endgroup$ – dave_thompson_085 Aug 15 '18 at 3:10

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