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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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.
fgrieu
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