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Actually, because of DESX works, the meet-in-the-middle attack can be optimized to take $2^{119}$ $DES$ (and no $DES^{-1}$ operations), and no additional storage. Here is how it works: let us assume that we have three known plaintext/ciphertext pairs $(P_1, C_1)$, $(P_2, C_2)$ and $(P_3, C_3)$. We know that: $$C_1 = K_2 \oplus DES( K, K_1 \oplus P_1 )$$ ...

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The key space for DES is far too small (56 bits). Therefore, any use of DES is not secure. It doesn't matter what mode you use. If the attacker has one plaintext, ciphertext pair, they can brute force the key space and recover the key in a feasible amount of time (24 hours using the cloud). But most importantly, how it could be made secure? Will change ...

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It is not at all secure if you fix the key and IV in the code, no matter what language you use. Ideally you should generate the key from a password based key derivative function like PBKDF2 or SCRYPT or provision the key from an external key management server. You also need to chose a encryption mode along with the scheme. The modes are picked based on the ...

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In general, the key length and number of rounds are the dominant factors in deciding cipher strength. But you need to consider how the rounds are constructed and how the key is used. Substitution and permutation are the bread and butter of DES. That's literally all it is - substitution, permutation, and XOR. Here is a diagram of the DES fiestel function ...

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I assume you are asking how the password a user enters to unlock their saved user data is translated into the keys used by 3DES? According to this link DES-EDE-CBC, which is only two-key 3DES. The first and third keys are set equal to each other, resulting in two keys of 56 bits or a total size of 112 bits. To get that key material from a password, a ...

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