def compute_session_key(self, salt, server_B):
'''Calculates client's session key and evidence message.'''
self.session_key = compute_hash(self.premaster_secret)
self.M = compute_M(self.g, self.N, self.username, salt, self.A,
server_B, self.session_key)
self.hashed_AMK = compute_hash(self.A, self.M, self.session_key)
return self.M
def apply_torque(self, u, dt=None):
if dt is None:
dt = self.dt
C2 = np.cos(self.theta[1][0])
S2 = np.sin(self.theta[1][0])
M11 = (self.K1 + self.K2 * C2)
M12 = (self.K3 + self.K4 * C2)
M21 = M12
M22 = self.K3
H1 = (-self.K2 * S2 * self.dtheta[0][0] * self.dtheta[1][0] -
1 / 2.0 * self.K2 * S2 * self.dtheta[1][0]**2.0)
H2 = 1. / 2. * self.K2 * S2 * self.dtheta[0][0]**2.0
ddq1 = ((H2 * M11 - H1 * M21 - M11 * u[1][0] + M21 * u[0][0]) /
(M12**2.0 - M11 * M22))
ddq0 = (-H2 + u[1][0] - M22 * ddq1) / M21
M = utils.compute_M(self.alpha, self.beta, self.delta, self.theta)
C = utils.compute_C(self.alpha, self.beta, self.delta, self.theta,
self.dtheta)
ddtheta = utils.fwd_dynamics(M, C, u, self.dtheta)
print ddtheta
print np.array([[ddtheta[0][0]], [ddtheta[1][1]]])
self.dtheta += np.array([[ddtheta[0][0]], [ddtheta[1][1]]]) * dt
self.theta += self.dtheta * dt
#self.dtheta += np.array([[ddq0], [ddq1]]) * dt
#self.theta += self.dtheta * dt
# move to next timestep
self.t += dt
def compute_session_key(self, username, salt, client_A):
'''
Calculates server's session key and evidence message.
M = H(H(N) XOR H(g) | H(U) | s | A | B | K)
H(A | M | K)
'''
self.session_key = compute_hash(self.premaster_secret)
self.M = compute_M(self.g, self.N, username, salt, client_A, self.B,
self.session_key)
self.hashed_AMK = compute_hash(client_A, self.M, self.session_key)
return self.M
def __init__(self):
# set up links and masses
self.l1 = 1.0
self.l2 = 1.0
self.m1 = 1.5
self.m2 = 1.5
# set starting configuration
self.theta[0] = 0.0
self.theta[1] = 0.0
# set dtheta as default 0 to begin with
self.dtheta[0] = 0.0
self.dtheta[1] = 0.0
# set (x,y) ee and elbow position
self.ee[0] = self.l1 * cos(self.theta[0])
self.ee[1] = self.l1 * sin(self.theta[0])
self.elbow[0] = self.ee[0] + self.l2 * cos(self.theta[0] +
self.theta[1])
self.elbow[1] = self.ee[1] + self.l2 * sin(self.theta[0] +
self.theta[1])
# compute constants
self.alpha = self.m1 * self.l1**2 + self.m2 * (self.l1**2 + self.l2**2)
self.beta = self.m2 * self.l1 * self.l2
self.delta = self.m2 * self.l2**2
# update M and C matrices given theta, dtheta information
self.M = utils.compute_M(self.alpha, self.beta, self.delta, self.theta)
self.C = utils.compute_C(self.alpha, self.beta, self.delta, self.theta,
self.dtheta)
self.t = 0.0
self.dt = 0.001
# compute non changing constants
self.K1 = ((1 / 3.0 * self.m1 + self.m2) * self.l1**2.0 +
1 / 3.0 * self.m2 * self.l2**2.0)
self.K2 = self.m2 * self.l1 * self.l2
self.K3 = 1 / 3.0 * self.m2 * self.l2**2.0
self.K4 = 1 / 2.0 * self.m2 * self.l1 * self.l2