Security 如何使用给定的Hashfunction和一些参数计算MAC的密钥?
我正在尝试计算消息身份验证码(MAC)的密钥。 现提供以下资料:Security 如何使用给定的Hashfunction和一些参数计算MAC的密钥?,security,key,ascii,Security,Key,Ascii,我正在尝试计算消息身份验证码(MAC)的密钥。 现提供以下资料: c_i = h(c_i-1, x_i) = c_i-1 xor x_i for i from 1 to z. Furthermore MAC_k(m) = c_z + key mod 2^8 And now I have These values: m = KINOSAAL (ASCII 8 Bit) MAC_k(m) = 01101011 and c_0 = 11111111 现在我尝试了这种方法,但我确信它一定是错的:(但
c_i = h(c_i-1, x_i) = c_i-1 xor x_i for i from 1 to z.
Furthermore MAC_k(m) = c_z + key mod 2^8
And now I have These values: m = KINOSAAL (ASCII 8 Bit)
MAC_k(m) = 01101011 and c_0 = 11111111
现在我尝试了这种方法,但我确信它一定是错的:(但也许有些方法是正确的,所以如果你们能帮我的话,我会很高兴
K = 4B
I = 49
N = 4E
O = 4F
S = 53
A = 41
A = 41
L = 4C
? = 3F
c0 = 11111111 = FF
MAC_k(m) = 01101011 = 6B
c1 = c0 xor x1 = FF xor 4B = B4
c2 = c1 xor x2 = B4 xor 49 = FD
c3 = c2 xor x3 = FD xor 4E = B3
c4 = c3 xor x4 = B3 xor 4F = FC
c5 = c4 xor x5 = FC xor 53 = AF
c6 = c5 xor x6 = AF xor 41 = EE
c7 = c6 xor x7 = EE xor 41 = AF
c8 = c7 xor x8 = AF xor 4C = E3
c9 = c8 xor x9 = E3 xor 3F = DC => c_z = DC (hex)
=> k = m xor cz = 6B xor DC = B7 (HEX)
这是我的方法。提前谢谢你,并致以亲切的问候