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panama.go
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panama.go
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package panama
import (
"strconv"
"crypto/cipher"
)
const NULL = 0
const WORDLENGTH = 32
const ONES = 0xffffffff
const PAN_STAGE_SIZE = 8
const PAN_STAGES = 32
const PAN_STATE_SIZE = 17
type KeySizeError int
func (k KeySizeError) Error() string {
return "cryptobin/panama: invalid key size " + strconv.Itoa(int(k))
}
type panamaCipher struct {
buffer PAN_BUFFER
stated PAN_STATE
wkeymat [8]uint32
keymat [32]byte
keymat_pointer int32
}
// NewCipher creates and returns a new cipher.Stream.
// key bytes and src bytes is use BigEndian
func NewCipher(key []byte) (cipher.Stream, error) {
k := len(key)
switch k {
case 32:
break
default:
return nil, KeySizeError(len(key))
}
c := new(panamaCipher)
c.buffer = PAN_BUFFER{}
c.stated = PAN_STATE{}
var in_key []uint32
keyints := bytesToUint32s(key[:16])
in_key = append(in_key, keyints[:]...)
keyints = bytesToUint32s(key[16:])
in_key = append(in_key, keyints[:]...)
c.expandKey(in_key, WORDLENGTH, nil, 0)
return c, nil
}
func (this *panamaCipher) expandKey(
in_key []uint32,
keysize int32,
init_vec []uint32,
vecsize int32,
) {
var keyblocks int32 = (8 * keysize) / (PAN_STAGE_SIZE * WORDLENGTH);
var vecblocks int32 = (8 * vecsize) / (PAN_STAGE_SIZE * WORDLENGTH);
/* initialize the Panama state machine for a fresh crypting operation */
this.pan_reset(&this.buffer, &this.stated)
this.pan_push(in_key, uint32(keyblocks), &this.buffer, &this.stated)
if len(init_vec) != 0 {
this.pan_push(init_vec, uint32(vecblocks), &this.buffer, &this.stated)
}
this.pan_pull(nil, nil, 32, &this.buffer, &this.stated);
wkeymat := this.pan_pull(nil, this.wkeymat[:], 1, &this.buffer, &this.stated)
copy(this.wkeymat[0:], wkeymat)
this.keymat_pointer = 0
this.keymat = keymatToBytes(this.wkeymat)
}
func (this *panamaCipher) XORKeyStream(dst, src []byte) {
if len(dst) < len(src) {
panic("cryptobin/panama: dst buffer is to small")
}
var i int32
/* initialize the Panama state machine for a fresh crypting operation */
for i = 0; i < int32(len(src)); i++ {
if this.keymat_pointer == 32 {
wkeymat := this.pan_pull(nil, this.wkeymat[:], 1, &this.buffer, &this.stated)
copy(this.wkeymat[0:], wkeymat)
this.keymat_pointer = 0
this.keymat = keymatToBytes(this.wkeymat)
}
dst[i] = src[i] ^ this.keymat[this.keymat_pointer]
this.keymat_pointer++
}
}
/**************************************************************************+
*
* pan_pull() - Performs multiple iterations of the Panama 'Pull' operation.
* The input and output arrays are treated as integer multiples
* of Panama's natural 256-bit block size.
*
* Input and output arrays may be disjoint or coincident but
* may not be overlapped if offset from one another.
*
* If 'In' is a NULL pointer then output is taken direct from
* the state machine (used for hash output). If 'Out' is a NULL
* pointer then a dummy 'Pull' is performed. Otherwise 'In' is
* XOR combined with the state machine to produce 'Out'
* (used for stream encryption / decryption).
*
+**************************************************************************/
func (this *panamaCipher) pan_pull(
In []uint32,
Out []uint32,
pan_blocks uint32,
buffer *PAN_BUFFER,
state *PAN_STATE,
) []uint32 {
/* 17-word finite-state machine */
var i uint32
data := NewData(17)
var tap_0 uint32
var ptap_0, ptap_25 *PAN_STAGE
var L, b *PAN_STAGE
var null_in = [PAN_STAGE_SIZE]uint32{ 0, 0, 0, 0, 0, 0, 0, 0 }
var dummy_out [PAN_STAGE_SIZE]uint32
var in_step, out_step uint32
in_step = PAN_STAGE_SIZE
out_step = PAN_STAGE_SIZE
if (len(In) == 0 || len(Out) == 0) {
In = null_in[:]
in_step = 0
}
if (len(Out) == 0) {
Out = dummy_out[:]
out_step = 0
}
/* copy buffer pointers and state to registers */
tap_0 = uint32(buffer.tap_0)
data.READ_STATE(state)
newOut := make([]uint32, len(Out))
/* rho, cascade of state update operations */
for i = 0; i < pan_blocks; i++ {
/* apply state output to crypto buffer */
Out[0] = In[0] ^ data.state[9]
Out[1] = In[1] ^ data.state[10]
Out[2] = In[2] ^ data.state[11]
Out[3] = In[3] ^ data.state[12]
Out[4] = In[4] ^ data.state[13]
Out[5] = In[5] ^ data.state[14]
Out[6] = In[6] ^ data.state[15]
Out[7] = In[7] ^ data.state[16]
copy(newOut[i*out_step:], Out[:8])
Out = Out[i*out_step:]
In = In[i*in_step:]
data.GAMMA() /* perform non-linearity stage */
data.PI() /* perform bit-dispersion stage */
data.THETA() /* perform diffusion stage */
/* calculate pointers to taps 4 and 16 for sigma based on current position of tap 0 */
L = &buffer.stage[(tap_0 + 4) & (PAN_STAGES - 1)]
b = &buffer.stage[(tap_0 + 16) & (PAN_STAGES - 1)]
/* move tap_0 left by one stage, equivalent to shifting LFSR one stage right */
tap_0 = (tap_0 - 1) & (PAN_STAGES - 1)
/* set tap pointers for use by lambda */
ptap_0 = &buffer.stage[tap_0]
ptap_25 = &buffer.stage[(tap_0 + 25) & (PAN_STAGES - 1)]
data.LAMBDA_PULL(i, ptap_25, ptap_0); /* update the LFSR buffer */
/* postpone sigma until after lambda in order to avoid extra temporaries for feedback path */
/* note that sigma gets to use the old positions of taps 4 and 16 */
data.SIGMA(L, b) /* perform buffer injection stage */
}
/* write buffer pointer and state back to memory */
buffer.tap_0 = int32(tap_0)
data.WRITE_STATE(state)
return newOut
}
/**************************************************************************+
*
* pan_push() - Performs multiple iterations of the Panama 'Push' operation.
* The input array is treated as an integer multiple of the
* 256-bit blocks which are Panama's natural input size.
*
+**************************************************************************/
func (this *panamaCipher) pan_push(
In []uint32,
pan_blocks uint32,
buffer *PAN_BUFFER,
state *PAN_STATE,
) {
/* 17-word finite-state machine */
var i uint32
data := NewData(17)
var tap_0 uint32
var ptap_0, ptap_25 *PAN_STAGE
var L []PAN_STAGE = make([]PAN_STAGE, 0)
var b *PAN_STAGE
/* copy buffer pointers and state to registers */
tap_0 = uint32(buffer.tap_0)
data.READ_STATE(state)
/* we assume pointer to input buffer is compatible with pointer to PAN_STAGE */
var pan_states [8]uint32
for i = 0; i < uint32(len(In)); i += PAN_STAGE_SIZE {
copy(pan_states[0:], In[i:])
L = append(L, PAN_STAGE{pan_states})
}
/* rho, cascade of state update operations */
for i = 0; i < pan_blocks; i++ {
data.GAMMA() /* perform non-linearity stage */
data.PI() /* perform bit-dispersion stage */
data.THETA() /* perform diffusion stage */
/* calculate pointer to tap 16 for sigma based on current position of tap 0 */
b = &buffer.stage[(tap_0 + 16) & (PAN_STAGES - 1)]
/* move tap_0 left by one stage, equivalent to shifting LFSR one stage right */
tap_0 = (tap_0 - 1) & (PAN_STAGES - 1)
/* set tap pointers for use by lambda */
ptap_0 = &buffer.stage[tap_0]
ptap_25 = &buffer.stage[(tap_0 + 25) & (PAN_STAGES - 1)]
data.LAMBDA_PUSH(i, ptap_25, ptap_0, &L[i]) /* update the LFSR buffer */
/* postpone sigma until after lambda in order to avoid extra temporaries for feedback path */
/* note that sigma gets to use the old positions of taps 4 and 16 */
data.SIGMA(&L[i], b) /* perform buffer injection stage */
/* In += PAN_STAGE_SIZE; */
}
/* write buffer pointer and state back to memory */
buffer.tap_0 = int32(tap_0)
data.WRITE_STATE(state)
}
/**************************************************************************+
*
* pan_reset() - Initializes an LFSR buffer and Panama state machine to
* all zeros, ready for a new hash to be accumulated or to
* re-synchronize or start up an encryption key-stream.
*
+**************************************************************************/
func (this *panamaCipher) pan_reset(buffer *PAN_BUFFER, state *PAN_STATE) {
var i, j int32
buffer.tap_0 = 0
for j = 0; j < PAN_STAGES; j++ {
for i = 0; i < PAN_STAGE_SIZE; i++ {
buffer.stage[j].word[i] = 0
}
}
for i = 0; i < PAN_STATE_SIZE; i++ {
state.word[i] = 0
}
}