def first_3SPboxes(reg, round_value):
# we need an additional register because we can't work on r28 r29 r30 r31
wk_reg, wk_reg2 = init_working(
) # additional registers used for computation : r24 - r31
reg = spbox(0, reg, wk_reg, wk_reg2)
wk_reg, wk_reg2 = init_working(
) # additional registers used for computation : r24 - r31
reg = spbox(3, reg, wk_reg, wk_reg2)
reg = small_swap(reg)
if round_value != 0:
AVR.LDI32(wk_reg, round_value) # load into the third register
AVR.EOR32(reg[0], wk_reg) # xor only the third register
wk_reg, wk_reg2 = init_working(
) # additional registers used for computation : r24 - r31
reg = spbox(3, reg, wk_reg, wk_reg2)
wk_reg, wk_reg2 = init_working(
) # additional registers used for computation : r24 - r31
reg = spbox(3, reg, wk_reg, wk_reg2)
wk_reg, wk_reg2 = init_working(
) # additional registers used for computation : r24 - r31
reg = spbox(0, reg, wk_reg, wk_reg2)
wk_reg, wk_reg2 = init_working(
) # additional registers used for computation : r24 - r31
reg = spbox(0, reg, wk_reg, wk_reg2)
return reg
def spbox(idx,reg, t0, t1):
x = reg[idx]
y = reg[idx+1]
z = reg[idx+2]
AVR.comment('START SPBOX')
AVR.comment('rotate x by 16: no register renaming')
AVR.PUSH(x[0])
AVR.MOV(x[0],x[3])
AVR.MOV(x[3],x[2])
AVR.MOV(x[2],x[1])
AVR.POP(x[1])
# 24 + 2 = 26
AVR.comment('rotate y by 9 : 1 + register renaming')
AVR.CLR0(t0)
AVR.ROL32(y,t0)
AVR.PUSH(y[0])
AVR.MOV(y[0],y[1])
AVR.MOV(y[1],y[2])
AVR.MOV(y[2],y[3])
AVR.POP(y[3])
AVR.comment('compute x')
AVR.MOVW32(t1,x)
AVR.MOVW32(t0,z)
AVR.LSL32(t0)
AVR.MOVW32(x,y)
AVR.AND32(x,z)
AVR.LSL32(x)
AVR.LSL32(x)
AVR.EOR32(x,t0)
AVR.EOR32(x,t1)
AVR.comment('compute y')
AVR.MOVW32(t0,y)
AVR.MOVW32(y,t1)
AVR.OR32(y,z)
AVR.LSL32(y)
AVR.EOR32(y,t1)
AVR.EOR32(y,t0)
AVR.comment('compute z')
AVR.AND32(t1,t0)
AVR.LSL32(t1)
AVR.LSL32(t1)
AVR.LSL32(t1)
AVR.EOR32(t0,t1)
AVR.EOR32(z,t0)
AVR.comment('swap x and z')
AVR.PUSH32(z)
AVR.MOV(z[0],x[0])
AVR.MOV(z[1],x[1])
AVR.MOV(z[2],x[2])
AVR.MOV(z[3],x[3])
AVR.POP32(x)
return reg
def spbox(idx, reg, t0, t1):
x = reg[idx]
y = reg[idx + 1]
z = reg[idx + 2]
AVR.comment('START SPBOX')
AVR.comment('rotate x by 16: register renaming')
# AVR.CLR0(t0)
# AVR.ROL32(x,t0)
# AVR.ROL32(x,t0)
AVR.rotate8(x) # rotate by 8
AVR.rotate8(x) # rotate by 8
AVR.rotate8(x) # rotate by 8
# 24 + 2 = 26
AVR.comment('rotate y by 9 : 1 + register renaming')
AVR.CLR0(t0)
AVR.ROL32(y, t0)
AVR.rotate8(y) # rotate by 8
# 8 + 1 = 9
AVR.comment('compute x')
AVR.MOVW32(t1, x)
AVR.MOVW32(t0, z)
AVR.LSL32(t0)
AVR.MOVW32(x, y)
AVR.AND32(x, z)
AVR.LSL32(x)
AVR.LSL32(x)
AVR.EOR32(x, t0)
AVR.EOR32(x, t1)
AVR.comment('compute y')
AVR.MOVW32(t0, y)
AVR.MOVW32(y, t1)
AVR.OR32(y, z)
AVR.LSL32(y)
AVR.EOR32(y, t1)
AVR.EOR32(y, t0)
AVR.comment('compute z')
AVR.AND32(t1, t0)
AVR.LSL32(t1)
AVR.LSL32(t1)
AVR.LSL32(t1)
AVR.EOR32(t0, t1)
AVR.EOR32(z, t0)
reg[idx], reg[idx + 2] = reg[idx + 2], reg[idx]
AVR.comment('END SPBOX')
return reg