讲解XJCO1212程序语言、辅导Python，Java程序、algorithms编程辅导
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Computer Processors (COMP1212/XJCO1212)
You should follow the instructions below on how to prepare your submission. Late submissions
are not accepted without mitigating circumstances. Feedback on late submissions
may not be provided within 3 weeks of submission.
Submission You must submit your work via Gradescope.
Deadline See Gradescope.
Weighting This piece of summative coursework is worth 25% of the module grade.
The Feistel cipher is a symmetric block cipher encryption framework which is the basis
of many modern day encryption algorithms. In this coursework you will implement a
Feistel cipher system as a hardware component and as a software implementation. In a
Feistel cipher the plaintext, P, to be encrypted is split into two equal size parts L0 and
R0 such that P = L0R0. A function F is applied to one half of the plaintext, combined
with a key, and the result is XOR’d with the other half of the plaintext. Feistel ciphers
often employ multiple rounds of this scheme. In general the scheme works as follows, for
all i = 0, . . . , n,
Li+1 = Ri
Ri+1 = Li ⊕ F(Ri
, Ki)
To decrypt an encrypted message using this cipher we can apply the same procedure
in reverse. For i = n, n − 1, . . . , 0,
Ri = Li+1
Li = Ri+1 ⊕ F(Li+1, Ki)
For this coursework we are interested in the 16-bit Feistel cipher which uses 4 rounds.
The function F(A, B) = A⊕B. The keys are derived from a single 8-bit key K0 such that,
K0 = b7b6b5b4b3b2b1b0
K1 = b6b5b4b3b2b1b0b7
K2 = b5b4b3b2b1b0b7b6
K3 = b4b3b2b1b0b7b6b5
1
1. Produce an implementation, in HDL, of the described Feistel encryption scheme. The
chip should have the following preamble.
CHIP FeistelEncryption {
IN plaintext[16], key[8];
OUT ciphertext[16];
PARTS:
}
2. Write a program in HACK assembly, without using symbols, that implements the
described Feistel encryption system. The initial key, K0, will be stored in RAM[1],
and the 16-bit plaintext will be stored in RAM[2]. The result of the encryption
should be stored in RAM[0]. Your solution should be submitted in a file called
“FeistelEncryption.asm”.
You may use any RAM locations not specified in the description for intermediate
variables.
Question 1 is worth 10 marks, and Question 2 is worth 15 marks.
2
Computer Processors (COMP1212/XJCO1212)
You should follow the instructions below on how to prepare your submission. Late submissions
are not accepted without mitigating circumstances. Feedback on late submissions
may not be provided within 3 weeks of submission.
Submission You must submit your work via Gradescope.
Deadline See Gradescope.
Weighting This piece of summative coursework is worth 25% of the module grade.
The Feistel cipher is a symmetric block cipher encryption framework which is the basis
of many modern day encryption algorithms. In this coursework you will implement a
Feistel cipher system as a hardware component and as a software implementation. In a
Feistel cipher the plaintext, P, to be encrypted is split into two equal size parts L0 and
R0 such that P = L0R0. A function F is applied to one half of the plaintext, combined
with a key, and the result is XOR’d with the other half of the plaintext. Feistel ciphers
often employ multiple rounds of this scheme. In general the scheme works as follows, for
all i = 0, . . . , n,
Li+1 = Ri
Ri+1 = Li ⊕ F(Ri
, Ki)
To decrypt an encrypted message using this cipher we can apply the same procedure
in reverse. For i = n, n − 1, . . . , 0,
Ri = Li+1
Li = Ri+1 ⊕ F(Li+1, Ki)
For this coursework we are interested in the 16-bit Feistel cipher which uses 4 rounds.
The function F(A, B) = A⊕B. The keys are derived from a single 8-bit key K0 such that,
K0 = b7b6b5b4b3b2b1b0
K1 = b6b5b4b3b2b1b0b7
K2 = b5b4b3b2b1b0b7b6
K3 = b4b3b2b1b0b7b6b5
1
1. Produce an implementation, in HDL, of the described Feistel encryption scheme. The
chip should have the following preamble.
CHIP FeistelEncryption {
IN plaintext[16], key[8];
OUT ciphertext[16];
PARTS:
}
2. Write a program in HACK assembly, without using symbols, that implements the
described Feistel encryption system. The initial key, K0, will be stored in RAM[1],
and the 16-bit plaintext will be stored in RAM[2]. The result of the encryption
should be stored in RAM[0]. Your solution should be submitted in a file called
“FeistelEncryption.asm”.
You may use any RAM locations not specified in the description for intermediate
variables.
Question 1 is worth 10 marks, and Question 2 is worth 15 marks.
2