unknown
plain_text
2 years ago
14 kB
37
Indexable
Never
```-----------------------------------------------------------------------------------------------
1. AES-V parameters: p=317, [a,b]=[13, 15], T=[1, 11, 31, 4]. The key K=[194, 210, 279, 102]

Decrypt the cipher C=[[280, 287, 72, 201], [80, 193, 17, 307], [92, 67, 307, 205], [199, 250, 186, 273], [60, 192, 59, 259], [258, 275, 197, 276], [23, 30, 23, 270], [228, 108, 22, 270], [24, 15, 307, 285], [165, 107, 311, 102], [30, 196, 40, 82], [30, 144, 167, 12], [154, 44, 238, 161], [219, 122, 168, 196], [134, 112, 63, 14], [275, 262, 66, 88], [251, 50, 245, 261], [101, 12, 234, 152], [108, 134, 173, 251], [220, 260, 291, 144], [67, 149, 90, 224], [292, 291, 251, 118]]
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2. The message block M=[240, 285, 239, 43] was encrypted twice  with AES-V using the keys K1=['?', 185, 276, 260], K2=[290, '?', 268, 190]

Find the key using the meet-in-the middle attack, if the cipher is  [208, 59, 195, 38]
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1. The plaintext starts with  TH
The text is encrypted using the keystream generated by system with 8 registers.Decrypt the cipher
[40, 230, 45, 217, 109, 50, 204, 188, 29, 104, 232, 204, 169, 41, 217, 135, 184, 10, 136, 105, 3, 132, 74, 180, 245, 50, 29, 94, 136, 152, 111, 211, 179, 235, 235, 57, 239, 214, 84, 186, 10, 175, 216, 114, 249, 247, 4, 95, 183, 60, 9, 180, 0, 76, 78, 164, 208, 158, 109, 35, 57, 43, 218, 88, 152, 171, 200, 161, 206, 65, 81, 144, 120, 244, 23, 137, 152, 136, 79, 106, 219, 132, 84, 136, 77, 93, 126, 254, 47, 49, 252, 252, 249, 219, 123, 22, 106, 212, 106, 203, 74, 105, 62, 26, 156, 172, 41, 62, 12, 119, 59, 247, 22, 96, 31, 91, 124, 1, 176, 237, 206, 145, 143, 166, 254, 13, 179, 62, 251, 58, 219, 105, 53, 200, 179, 23, 126, 230, 200, 160, 46, 212, 144, 189, 25, 149, 105, 19, 132, 71, 174, 238, 50, 15, 94, 142, 152, 106, 201, 183, 253, 241, 44, 243, 215, 68, 161, 25, 188, 211, 120, 243, 230, 15, 78, 162, 54, 22, 188, 2, 74, 78, 184, 212, 132, 105, 33, 34, 35, 195, 86, 159, 181, 192, 172, 193, 69, 94, 129, 123, 255, 21, 159, 130, 128, 95, 124, 212, 131, 87, 137, 69, 93, 118, 254, 34, 48, 245, 242, 238, 199, 117, 26, 101, 206, 102, 222, 81, 111, 49, 7, 155, 185, 51, 55, 18, 97, 52, 252, 14, 119, 14, 68, 100, 1, 183, 231, 218, 135, 149, 162, 247, 30, 164, 62, 235, 58, 202, 122, 33, 207, 185, 28, 125, 227, 223, 168, 34, 210, 138, 180, 21, 157, 117, 4, 128, 81, 163, 239, 57, 31, 94, 150, 149, 106, 194, 183, 247, 225, 61, 245, 202, 78, 166, 27, 175, 197, 99, 253, 247, 0, 89, 160, 50, 16, 180, 16, 80, 77, 184, 220, 156, 103, 59, 35, 54, 193, 66, 141, 174, 192, 172, 197, 90, 70, 133, 103, 251, 22, 159, 154, 144, 79, 102, 198, 132, 93, 132, 88, 88, 112, 255, 52, 53, 255, 249, 244, 215, 121, 13, 120, 219, 105, 206, 85, 111, 45, 17, 143, 170, 32, 52, 9, 96, 57, 240, 16, 96, 0, 92, 121, 19, 170, 230, 207, 155, 135, 184, 242, 9, 183, 53, 234, 35, 223, 96, 46]
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2. The plaintext is encrypted using three identical LFBR as in 1 assignment.
Encryption performed as in a5/1 scheme; the  1,2,3  registers are controlling.
The registers are indexed starting with 0.
The initial states of registers are the same as the vectors of coefficients.
Decrypt the cipher
[126, 83, 170, 130, 176, 19, 121, 150, 35, 233, 63, 6, 73, 150, 113, 137, 72, 144, 102, 209, 167, 233, 20, 201, 190, 244, 179, 94, 50, 114, 27, 2, 171, 206, 103, 250, 225, 14, 69, 162, 39, 12, 180, 14, 69, 76, 162, 208, 147, 109, 59, 34, 43, 192, 68, 157, 174, 192, 161, 206, 64, 94, 145, 127, 255, 28, 138, 153, 157, 84, 106, 209, 159, 86, 156, 74, 69, 108, 235, 33, 50, 240, 244, 255, 223, 121, 11, 106, 210, 102, 216, 81, 105, 49, 23, 129, 167, 55, 41, 26, 119, 36, 233, 22, 103, 28, 92, 127, 20, 183, 231, 202, 157, 148, 186, 242, 31, 160, 46, 231, 60, 214, 109, 33, 197, 176, 26, 105, 228, 193, 185, 53, 194, 144, 182, 19, 156, 126, 2, 142, 72, 191, 225, 50, 25, 86, 155, 151, 109, 196, 164, 248, 238, 59, 238, 198, 66, 166, 13, 160, 210, 103, 249, 243, 30, 78, 161, 50, 10, 184, 14, 84, 64, 184, 205, 156, 98, 59, 57, 43, 194, 82, 131, 168, 218, 167, 208, 77, 77, 148, 127, 244, 25, 136, 151, 133, 89, 97, 210, 140, 84, 128, 65, 85, 113, 254, 52, 48, 228, 239, 228, 220, 127, 11, 99, 223, 112, 203, 74, 110, 48, 0, 143, 171, 47, 34, 18, 106, 52, 251, 3, 113, 12, 64, 121, 14, 185, 228, 220, 152, 137, 164, 241, 13, 179, 49, 239, 38, 205, 103, 50, 213, 180, 22, 104, 236, 195, 185, 35, 197, 138, 188, 18, 158, 110, 4, 137, 80, 191, 231, 35, 3, 90, 142, 149, 102, 193, 166, 246, 246, 48, 228, 192, 70, 161, 24, 162, 211, 100, 250, 244, 3, 68, 162, 52, 1, 163, 1, 69, 65, 161, 216, 147, 104, 37, 62, 48, 194, 86, 132, 162, 200, 177, 210, 64, 90, 151, 97, 243, 12, 151, 133, 129, 90, 99, 208, 136, 71, 146, 77, 67, 108, 239, 41, 32, 254, 232, 249, 198, 119, 22, 101, 206, 98, 216, 91, 101, 47, 0, 154, 161, 38, 54, 19, 107, 39, 251, 1, 113, 29, 93, 100, 19, 179, 230, 206, 134, 143, 187, 230, 7, 179, 40, 239, 38, 202, 107, 47, 207, 169, 1, 114, 231, 216, 185, 37, 222, 140, 174, 29, 130, 108, 2, 142, 65, 187, 228, 59, 18, 82, 148, 157, 102, 198, 160, 224, 242, 44, 232, 204, 64, 161, 4, 171, 204, 126, 248, 255, 2, 89, 168, 50, 10, 191, 23, 65, 67, 175, 222, 143, 109, 34, 42, 39, 207, 85, 134, 163, 207, 176, 201, 69, 75, 157, 118, 253, 29, 140, 155, 136, 82, 105, 218, 159, 86, 140, 75, 94, 112, 236, 33, 61, 242, 248, 254, 215, 118, 11, 125, 211, 102, 221, 89, 115, 55, 29, 128, 174, 55, 52, 21, 112, 63, 247, 3, 103, 14, 89, 114, 1, 173, 250, 220, 150, 137, 164, 254, 13, 168, 50, 252, 33, 221, 96, 54, 206, 179, 22, 120, 238, 204, 191, 40, 197, 139, 183, 17, 148, 100, 25, 130, 76, 173, 238, 62, 8, 83, 138, 149, 98, 220, 183, 253, 227, 53, 224, 200, 72, 167, 28, 175, 196, 99, 252, 252, 5, 89, 172, 61, 3, 184, 13, 67, 91, 162, 220, 136, 98, 38, 63, 33, 202, 68, 158, 167, 221, 167, 213, 65, 81, 129, 124, 238, 16, 155, 129, 136, 78]
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1. Coefficients and initial state [1, 0, 1, 0, 1, 0, 1, 1]
Plaintext
I cipher
[142, 66, 32, 153, 80, 57, 151, 78, 43, 146, 67, 34, 149, 84, 39, 157, 83, 34, 153, 74, 43, 136, 78, 41, 157, 75, 41, 149, 87, 34, 153, 85, 40, 137, 85, 47, 157, 82, 41, 147, 75, 38, 153, 70, 45, 137, 66, 57, 150, 66, 56, 134, 94, 56, 133, 68, 33, 149, 70, 36, 152, 79, 47, 146, 85, 51, 151, 93, 51, 155, 70, 38, 143, 76, 35, 159, 72, 36, 136, 78, 36, 137, 66, 46, 142, 66, 43, 152, 78, 36, 155, 66, 36, 149, 64, 39, 157, 70, 36, 152, 76, 47, 153, 87, 35, 146, 64, 58, 157, 68, 47, 139, 78, 62, 148, 83, 34, 153, 66, 60, 147, 75, 63, 136, 78, 37, 146, 72, 44, 136, 79, 47, 155, 66, 56, 145, 70, 36, 157, 85, 39, 133, 74, 43, 159, 79, 35, 146, 66, 57, 159, 72, 39, 140, 72, 36, 153, 73, 62, 143, 70, 36, 152, 66, 36, 159, 78, 58, 148, 66, 56, 145, 66, 36, 136, 87, 56, 147, 68, 47, 152, 82, 56, 153, 84, 43, 143, 83, 34, 153, 87, 37, 144, 66, 57, 142, 66, 57, 147, 82, 56, 159, 66, 57, 158, 66, 41, 157, 74, 47, 143, 83, 56, 157, 78, 36, 153, 67, 40, 133, 83, 34, 153, 68, 34, 157, 73, 45, 153, 84, 40, 153, 78, 36, 155, 78, 36, 136, 85, 37, 152, 82, 41, 153, 67, 40, 133, 83, 34, 153, 64, 47, 142, 74, 43, 146, 84, 43, 146, 67, 43, 143, 80, 43, 142, 75, 37, 147, 74, 47, 152, 83, 34, 153, 68, 35, 140, 79, 47, 142, 69, 63, 142, 66, 43, 137, 72, 36, 136, 79, 47, 140, 72, 38, 149, 84, 34, 155, 66, 36, 153, 85, 43, 144, 84, 62, 157, 65, 44, 143, 78, 36, 143, 83, 56, 137, 68, 62, 149, 72, 36, 143, 72, 36, 150, 82, 38, 133, 70, 62, 139, 70, 56, 143, 70, 61, 149, 73, 35, 136, 78, 43, 136, 66, 46, 154, 85, 47, 146, 68, 34, 157, 73, 46, 158, 85, 35, 136, 78, 57, 148, 78, 36, 136, 66, 38, 144, 78, 45, 153, 73, 41, 153, 85, 47, 140, 85, 47, 143, 66, 36, 136, 70, 62, 149, 81, 47, 143, 78, 36, 136, 72, 62, 148, 66, 57, 153, 68, 56, 153, 83, 57, 147, 65, 47, 146, 78, 45, 145, 70, 46, 153, 68, 56, 133, 87, 62, 149, 72, 36]
II cipher
[175, 64, 79, 64, 82, 86, 78, 76, 68, 75, 65, 77, 76, 86, 72, 68, 81, 77, 64, 72, 68, 81, 76, 70, 68, 73, 70, 76, 85, 77, 64, 87, 71, 80, 87, 64, 68, 80, 70, 74, 73, 73, 64, 68, 66, 80, 64, 86, 79, 64, 87, 95, 92, 87, 92, 70, 78, 76, 68, 75, 65, 77, 64, 75, 87, 92, 78, 95, 92, 66, 68, 73, 86, 78, 76, 70, 74, 75, 81, 76, 75, 80, 64, 65, 87, 64, 68, 65, 76, 75, 66, 64, 75, 76, 66, 72, 68, 68, 75, 65, 78, 64, 64, 85, 76, 75, 66, 85, 68, 70, 64, 82, 76, 81, 77, 81, 77, 64, 64, 83, 74, 73, 80, 81, 76, 74, 75, 74, 67, 81, 77, 64, 66, 64, 87, 72, 68, 75, 68, 87, 72, 92, 72, 68, 70, 77, 76, 75, 64, 86, 70, 74, 72, 85, 74, 75, 64, 75, 81, 86, 68, 75, 65, 64, 75, 70, 76, 85, 77, 64, 87, 72, 64, 75, 81, 85, 87, 74, 70, 64, 65, 80, 87, 64, 86, 68, 86, 81, 77, 64, 85, 74, 73, 64, 86, 87, 64, 86, 74, 80, 87, 70, 64, 86, 71, 64, 70, 68, 72, 64, 86, 81, 87, 68, 76, 75, 64, 65, 71, 92, 81, 77, 64, 70, 77, 68, 75, 66, 64, 86, 71, 64, 76, 75, 66, 76, 75, 81, 87, 74, 65, 80, 70, 64, 65, 71, 92, 81, 77, 64, 66, 64, 87, 72, 68, 75, 86, 68, 75, 65, 68, 86, 82, 68, 87, 73, 74, 74, 72, 64, 65, 81, 77, 64, 70, 76, 85, 77, 64, 87, 71, 80, 87, 64, 68, 80, 74, 75, 81, 77, 64, 85, 74, 73, 76, 86, 77, 66, 64, 75, 64, 87, 68, 73, 86, 81, 68, 67, 67, 86, 76, 75, 86, 81, 87, 80, 70, 81, 76, 74, 75, 86, 74, 75, 79, 80, 73, 92, 68, 81, 82, 68, 87, 86, 68, 82, 76, 75, 76, 81, 76, 68, 81, 64, 65, 67, 87, 64, 75, 70, 77, 68, 75, 65, 71, 87, 76, 81, 76, 86, 77, 76, 75, 81, 64, 73, 73, 76, 66, 64, 75, 70, 64, 87, 64, 85, 87, 64, 86, 64, 75, 81, 68, 81, 76, 83, 64, 86, 76, 75, 81, 74, 81, 77, 64, 86, 64, 70, 87, 64, 81, 86, 74, 67, 64, 75, 76, 66, 72, 68, 65, 64, 70, 87, 92, 85, 81, 76, 74, 75]
Convert the plaintext and ciphertext to bitstreams and apply the statistical tests.
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1. The knapsack cryptosystem public key is [v_1,...,v_8,p]  [45520925, 32675006, 50435685, 61248038, 66145386, 21175683, 51863800, 10339236, 90041003].
The first weight of private key is w_1=659792.
Decrypt the knapsack cipher
[47655442, 52552790, 16140523, 80390757, 14245371, 50435685, 54317726, 24584607, 3408924, 55272724, 24584607]
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2. The Graham-Shamir knapsack cryptosystem public key is [v_1,...,v_8,p]  [23707590458, 40701543144, 33252647798, 59198994592, 265712981, 109548959808, 13414055034, 115122611251, 120872500953].
The first weight of private key is w_1=20104740989.
The message is hidden as 11-18 bits (counting from the end of string).
Decrypt the knapsack cipher
[26479759, 69554310, 688990, 54317726, 80390757, 69554310, 55272724, 69554310, 75493409, 40761345]
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The key for verification of Alice signatures and encryption in ElGamal scheme is
[p,g,bt]=[4640650289117164100520051333566036654627, 2, 942747977147748786689896236690690442282]
Alice signed the message= citizenship. Signature:
[gamma, delta_1]=[1755363083651359377081276458980567304289, 1244781112948510837058403742426223178764]
Alice signed the message= educated people. Signature:
[gamma, delta_2]=[1755363083651359377081276458980567304289, 4043286555096320270616409318387824541589]

1. Verify the signatures.
2. Find the private key of Alice.
3. Decrypt the cipher send to Alice
[C_1,C_2]=[2883202309325208963244057668236002339264, 2564995139027898118803765088005826380379]
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1. Given the elliptic curve G = EllipticCurve(GF(3001),[-7,2]) and the point P[21 : 2819] of prime order p=509.

The private key of Menezes-Vanstone cryptosystem is r=400.
Decrypt the cipher
[[[1558, 1314], 185, 321], [[2885, 523], 231, 6], [[73, 2873], 19, 395], [[851, 1870], 180, 159], [[1924, 2113], 66, 35], [[536, 2198], 422, 103], [[1382, 1734], 65, 59], [[1473, 2541], 451, 27]]
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2. Sign the message m=100 using El Gamal signature with the elliptic curve and the private key given.
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