{
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{
"cell_type": "code",
"execution_count": 1,
"id": "054915e4",
"metadata": {},
"outputs": [
{
"data": {
"text/html": [
"\n"
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"text/plain": [
""
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"metadata": {},
"output_type": "display_data"
}
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"source": [
"%%HTML\n",
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{
"cell_type": "code",
"execution_count": 11,
"id": "62243eff",
"metadata": {
"jupyter": {
"source_hidden": true
}
},
"outputs": [
{
"data": {
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"execution_count": 11,
"metadata": {},
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"source": [
"def id2bit(ls: list):\n",
" \"\"\"\n",
" Converts a list of indices into a binary representation (bit vector).\n",
"\n",
" Given a list of indices (ls), this function returns a list of bits where\n",
" the bit positions corresponding to the indices in the list are set to 1,\n",
" and all other positions are set to 0. The resulting list is reversed.\n",
"\n",
" Args:\n",
" ls (list): A list of indices to be converted to bits.\n",
"\n",
" Returns:\n",
" list: A list of bits representing the binary values.\n",
" \"\"\"\n",
" if len(ls) == 0:\n",
" return [0, 0, 0, 0, 0, 0, 0, 0] # Return a default 8-bit array\n",
" aa = [0 for _ in range(max(ls) + 1)]\n",
" for i in ls:\n",
" aa[i] = 1\n",
" return aa[::-1]\n",
"\n",
"\n",
"def bit2id(ls: list, log=False):\n",
" \"\"\"\n",
" Converts a binary list (bit vector) back to a list of indices.\n",
"\n",
" Given a list of bits (ls), this function returns the indices of the bits\n",
" that are set to 1. The binary list is reversed during the conversion.\n",
"\n",
" Args:\n",
" ls (list): A list of bits representing a binary value.\n",
" log (bool, optional): Whether to log intermediate steps (default is False).\n",
"\n",
" Returns:\n",
" list: A list of indices where the bits are set to 1.\n",
" \"\"\"\n",
" ls = ls[::-1]\n",
" aa = []\n",
"\n",
" for i in range(len(ls)):\n",
" if ls[i] == 1:\n",
" aa.append(i)\n",
" return aa[::-1]\n",
"\n",
"\n",
"def bit2mul(a, b, log=False):\n",
" \"\"\"\n",
" Multiplies two binary numbers represented as lists of bits.\n",
"\n",
" This function multiplies two binary numbers by performing a bitwise\n",
" multiplication and addition over Galois Field (GF(2)).\n",
"\n",
" Args:\n",
" a (list): A list of bits representing the first binary number.\n",
" b (list): A list of bits representing the second binary number.\n",
" log (bool, optional): Whether to log intermediate steps (default is False).\n",
"\n",
" Returns:\n",
" list: The resulting binary number (list of bits).\n",
" \"\"\"\n",
" ai = bit2id(a)\n",
" bi = bit2id(b)\n",
" a, b = a[::-1], b[::-1]\n",
"\n",
" if ai == []:\n",
" return a\n",
" elif bi == []:\n",
" return b\n",
"\n",
" addn = [[ai[i] + bi[j] for j in range(len(bi))][::-1] for i in range(len(ai))][::-1]\n",
" addn = [id2bit(i) for i in addn]\n",
"\n",
" maxsiz = max([len(i) for i in addn])\n",
" for i in range(len(addn)):\n",
" if len(addn[i]) < maxsiz:\n",
" addn[i] = [0 for _ in range(maxsiz - len(addn[i]))] + addn[i]\n",
"\n",
" smm = []\n",
" for i in range(maxsiz):\n",
" t = 0\n",
" for j in addn:\n",
" t += j[i]\n",
" smm.append(t % 2)\n",
"\n",
" return smm\n",
"\n",
"\n",
"def bit2add(a, b):\n",
" \"\"\"\n",
" Adds two binary numbers represented as lists of bits (bitwise addition).\n",
"\n",
" This function adds two binary numbers by performing a bitwise addition over GF(2).\n",
"\n",
" Args:\n",
" a (list): A list of bits representing the first binary number.\n",
" b (list): A list of bits representing the second binary number.\n",
"\n",
" Returns:\n",
" list: The resulting binary number after addition (list of bits).\n",
" \"\"\"\n",
" a, b = list(a), list(b)\n",
" a, b = a[::-1], b[::-1]\n",
" maxsiz = max(len(a), len(b))\n",
"\n",
" if len(a) < maxsiz:\n",
" a = a + [0 for _ in range(maxsiz - len(a))]\n",
" if len(b) < maxsiz:\n",
" b = b + [0 for _ in range(maxsiz - len(b))]\n",
"\n",
" smm = []\n",
" for i in range(maxsiz):\n",
" smm.append((a[i] + b[i]) % 2)\n",
"\n",
" return smm[::-1]\n",
"\n",
"\n",
"def bit2str(bit: list):\n",
" \"\"\"\n",
" Converts a list of bits into a string.\n",
"\n",
" This function converts a list of binary bits (0s and 1s) into a string of characters.\n",
"\n",
" Args:\n",
" bit (list): A list of bits (0s and 1s).\n",
"\n",
" Returns:\n",
" str: The string representation of the binary bits.\n",
" \"\"\"\n",
" s = \"\"\n",
" for i in bit:\n",
" s += str(i)\n",
" return s\n",
"\n",
"\n",
"def str2bit(s: str):\n",
" \"\"\"\n",
" Converts a string of '0's and '1's into a list of bits.\n",
"\n",
" This function converts a string containing '0's and '1's into a list of integer bits.\n",
"\n",
" Args:\n",
" s (str): A string containing '0's and '1's.\n",
"\n",
" Returns:\n",
" list: A list of bits (integers).\n",
"\n",
" Raises:\n",
" ValueError: If the string contains characters other than '0' and '1'.\n",
" \"\"\"\n",
" if set(s).issubset(set(\"01\")):\n",
" bit = [int(i) for i in s]\n",
" return bit\n",
" else:\n",
" print(\"bit string should contain 1s and 0s\")\n",
"\n",
"\n",
"def modgf(dsr: list, dnt=[1, 0, 0, 0, 1, 1, 0, 1, 1]):\n",
" \"\"\"\n",
" Performs polynomial division over Galois Field (GF(2)).\n",
"\n",
" This function divides the binary polynomial `dsr` by the binary polynomial `dnt`\n",
" and returns the quotient and remainder.\n",
"\n",
" Args:\n",
" dsr (list): The dividend as a list of bits (binary polynomial).\n",
" dnt (list, optional): The divisor as a list of bits (default is a predefined irreducible polynomial).\n",
"\n",
" Returns:\n",
" tuple: The remainder and quotient as lists of bits.\n",
" \"\"\"\n",
" dsr = bit2id(dsr)\n",
" dnt = bit2id(dnt)\n",
" qtnt = []\n",
"\n",
" while len(dnt) != 0 and len(dsr) != 0 and (max(dnt) - max(dsr) >= 0):\n",
" ml = max(dnt) - max(dsr)\n",
" qtnt.append(ml)\n",
" plus = id2bit(dnt)\n",
" minus = id2bit([ml + i for i in dsr])\n",
" rem = bit2add(plus, minus)\n",
" dnt = bit2id(rem)\n",
"\n",
" return id2bit(dnt), id2bit(qtnt)\n",
"\n",
"\n",
"def ext_eucld(a, b, log=False):\n",
" \"\"\"\n",
" Extended Euclidean algorithm for binary polynomials.\n",
"\n",
" This function computes the extended Euclidean algorithm for binary polynomials `a` and `b`,\n",
" returning the coefficients of the linear combination of `a` and `b` that equals the greatest common divisor (GCD).\n",
"\n",
" Args:\n",
" a (list): A list of bits representing the first binary polynomial.\n",
" b (list): A list of bits representing the second binary polynomial.\n",
" log (bool, optional): Whether to log intermediate steps (default is False).\n",
"\n",
" Returns:\n",
" list: The coefficients of the linear combination of `a` and `b` (as lists of bits).\n",
" \"\"\"\n",
" ai, bi = bit2id(a), bit2id(b)\n",
" if len(ai) != 0 and len(bi) != 0:\n",
" if max(max(ai), max(bi)) == max(bi):\n",
" a, b = b, a\n",
" elif len(ai) == 0 and len(bi) != 0:\n",
" a, b = b, a\n",
"\n",
" def eucld(a, b, log=False):\n",
" a, b = a[::-1], b[::-1]\n",
"\n",
" if set(b) == set([0]) or (b[0] == 1 and (set(b[1:]) == set([0]))):\n",
" return []\n",
"\n",
" ls = []\n",
"\n",
" while not (b[0] == 1 and (set(b[1:]) == set([0]))):\n",
" r, idx = modgf(b[::-1], dnt=a[::-1])\n",
" r, idx = r[::-1], idx[::-1]\n",
"\n",
" if set(r) == set([0]):\n",
" return ls\n",
"\n",
" ls.append(idx[::-1])\n",
" a = b\n",
" b = r\n",
" return ls\n",
"\n",
" row = [\n",
" [[0, 0, 0, 0, 0, 0, 0, 1], [0, 0, 0, 0, 0, 0, 0, 0]],\n",
" [[0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 1]],\n",
" ]\n",
"\n",
" ls = eucld(a, b)\n",
" for i in ls:\n",
" r10, r11 = row[-1][0], row[-1][1]\n",
" r20, r21 = row[-2][0], row[-2][1]\n",
" r0 = bit2add(r20, bit2mul(r10, i))\n",
" r1 = bit2add(r21, bit2mul(r11, i))\n",
" rowl = [r0, r1]\n",
" row.append(rowl)\n",
"\n",
" return row[-1]\n",
"\n",
"\n",
"def Gfinv(bit, irrpoly=[1, 0, 0, 0, 1, 1, 0, 1, 1]):\n",
" \"\"\"\n",
" Computes the multiplicative inverse of a binary polynomial over GF(2).\n",
"\n",
" This function uses the extended Euclidean algorithm to compute the inverse of a binary polynomial `bit`\n",
" with respect to a predefined irreducible polynomial `irrpoly`.\n",
"\n",
" Args:\n",
" bit (list): A list of bits representing the binary polynomial to be inverted.\n",
" irrpoly (list, optional): The irreducible polynomial used for the field (default is a predefined polynomial).\n",
"\n",
" Returns:\n",
" list: The multiplicative inverse of the polynomial `bit` (list of bits).\n",
" \"\"\"\n",
" if set(bit) == set(\"0\"):\n",
" return \"--\"\n",
"\n",
" ans = ext_eucld(irrpoly, bit)\n",
" ans = ans[-1][-len(bit) :]\n",
" return ans\n",
"\n",
"\n",
"# Example call\n",
"Gfinv([0, 0, 0, 0, 0, 1, 0, 0], irrpoly=[0, 0, 0, 1, 0, 0, 1, 1])"
]
},
{
"cell_type": "code",
"execution_count": 4,
"id": "0c2b9aab",
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"[0, 0, 0, 0, 1, 1, 0, 1]\n"
]
}
],
"source": [
"def id2bit(ls: list):\n",
" if len(ls) == 0:\n",
" return [0, 0, 0, 0, 0, 0, 0, 0] # Return a default 8-bit array\n",
" aa = [0 for _ in range(max(ls) + 1)]\n",
" for i in ls:\n",
" aa[i] = 1\n",
" return aa[::-1]\n",
"\n",
"def bit2id(ls: list, log=False):\n",
" ls = ls[::-1]\n",
" aa = []\n",
" for i in range(len(ls)):\n",
" if ls[i] == 1:\n",
" aa.append(i)\n",
" return aa[::-1]\n",
"\n",
"def bit2mul(a, b, log=False):\n",
" ai = bit2id(a)\n",
" bi = bit2id(b)\n",
" a, b = a[::-1], b[::-1]\n",
" \n",
" if ai == []:\n",
" return a\n",
" elif bi == []:\n",
" return b\n",
" \n",
" addn = [[ai[i] + bi[j] for j in range(len(bi))][::-1] for i in range(len(ai))][::-1]\n",
" addn = [id2bit(i) for i in addn]\n",
" \n",
" maxsiz = max([len(i) for i in addn])\n",
" for i in range(len(addn)):\n",
" if len(addn[i]) < maxsiz:\n",
" addn[i] = [0 for _ in range(maxsiz - len(addn[i]))] + addn[i]\n",
" \n",
" smm = []\n",
" for i in range(maxsiz):\n",
" t = 0\n",
" for j in addn:\n",
" t += j[i]\n",
" smm.append(t % 2)\n",
" \n",
" return smm\n",
"\n",
"def bit2add(a, b):\n",
" a, b = list(a), list(b)\n",
" a, b = a[::-1], b[::-1]\n",
" maxsiz = max(len(a), len(b))\n",
" \n",
" if len(a) < maxsiz:\n",
" a = a + [0 for _ in range(maxsiz - len(a))]\n",
" if len(b) < maxsiz:\n",
" b = b + [0 for _ in range(maxsiz - len(b))]\n",
" \n",
" smm = []\n",
" for i in range(maxsiz):\n",
" smm.append((a[i] + b[i]) % 2)\n",
" \n",
" return smm[::-1]\n",
"\n",
"def bit2str(bit: list):\n",
" s = \"\"\n",
" for i in bit:\n",
" s += str(i)\n",
" return s\n",
"\n",
"def str2bit(s: str):\n",
" if set(s).issubset(set('01')):\n",
" bit = [int(i) for i in s]\n",
" return bit\n",
" else:\n",
" print(\"bit string should contain 1s and 0s\")\n",
"\n",
"def modgf(dsr: list, dnt=None):\n",
" if dnt is None:\n",
" dnt = [1, 0, 0, 0, 1, 1, 0, 1, 1]\n",
" \n",
" dsr = bit2id(dsr)\n",
" dnt = bit2id(dnt)\n",
" qtnt = []\n",
" \n",
" while len(dnt) != 0 and len(dsr) != 0 and (max(dnt) - max(dsr) >= 0):\n",
" ml = max(dnt) - max(dsr)\n",
" qtnt.append(ml)\n",
" plus = id2bit(dnt)\n",
" minus = id2bit([ml + i for i in dsr])\n",
" rem = bit2add(plus, minus)\n",
" dnt = bit2id(rem)\n",
" \n",
" return id2bit(dnt), id2bit(qtnt)\n",
"\n",
"def ext_eucld(a, b, log=False):\n",
" ai, bi = bit2id(a), bit2id(b)\n",
" if len(ai) != 0 and len(bi) != 0:\n",
" if max(max(ai), max(bi)) == max(bi):\n",
" a, b = b, a\n",
" elif len(ai) == 0 and len(bi) != 0:\n",
" a, b = b, a\n",
" \n",
" def eucld(a, b, log=False):\n",
" a, b = a[::-1], b[::-1]\n",
" \n",
" if set(b) == set([0]) or (b[0] == 1 and set(b[1:]) == set([0])):\n",
" return []\n",
" \n",
" ls = []\n",
" \n",
" while not (b[0] == 1 and set(b[1:]) == set([0])):\n",
" r, idx = modgf(b[::-1], dnt=a[::-1])\n",
" r, idx = r[::-1], idx[::-1]\n",
" \n",
" if set(r) == set([0]):\n",
" return ls\n",
" \n",
" ls.append(idx[::-1])\n",
" a = b\n",
" b = r\n",
" return ls\n",
" \n",
" row = [[[0, 0, 0, 0, 0, 0, 0, 1], [0, 0, 0, 0, 0, 0, 0, 0]],\n",
" [[0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 1]]]\n",
" \n",
" ls = eucld(a, b)\n",
" for i in ls:\n",
" r10, r11 = row[-1][0], row[-1][1]\n",
" r20, r21 = row[-2][0], row[-2][1]\n",
" r0 = bit2add(r20, bit2mul(r10, i))\n",
" r1 = bit2add(r21, bit2mul(r11, i))\n",
" rowl = [r0, r1]\n",
" row.append(rowl)\n",
" \n",
" return row[-1]\n",
"\n",
"def Gfinv(bit, irrpoly=None):\n",
" if irrpoly is None:\n",
" irrpoly = [1, 0, 0, 0, 1, 1, 0, 1, 1]\n",
" \n",
" if set(bit) == set([0]):\n",
" return '--'\n",
" \n",
" ans = ext_eucld(irrpoly, bit)\n",
" ans = ans[-1][-len(bit):]\n",
" return ans\n",
"\n",
"# Example call\n",
"print(Gfinv([0, 0, 0, 0, 0, 1, 0, 0], irrpoly=[0, 0, 0, 1, 0, 0, 1, 1]))\n"
]
},
{
"cell_type": "code",
"execution_count": 5,
"id": "edb53805",
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"[0, 0, 0, 0, 1, 1, 0, 1]"
]
},
"execution_count": 5,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"def genmapping(n: int, irrpoly):\n",
" \"\"\"\n",
" Generates the elements of GF(2^n) and their corresponding multiplicative inverses\n",
" based on the provided irreducible polynomial.\n",
"\n",
" Parameters:\n",
" n (int): The size of the Galois Field (GF(2^n)). Determines the number of elements\n",
" in the field, which is 2^n.\n",
" irrpoly (list): A list of bits representing the irreducible polynomial used\n",
" for the finite field operations (e.g., [1, 0, 0, 1] for x^3 + 1).\n",
"\n",
" Returns:\n",
" tuple: A tuple containing:\n",
" - gf (list): A list of binary strings of length `n`, representing all elements\n",
" of GF(2^n). The binary strings are padded with leading zeros.\n",
" - invmap (dict): A dictionary mapping the index of each element in `gf` to the\n",
" index of its multiplicative inverse, using the irreducible\n",
" polynomial for the field.\n",
"\n",
" Example:\n",
" gf, invmap = genmapping(3, [1, 0, 0, 1])\n",
" # gf will contain the elements ['000', '001', '010', '011', '100', '101', '110', '111']\n",
" # invmap will contain a mapping of the inverses for each non-zero element.\n",
" \"\"\"\n",
" gf = [str(bin(i))[2:] for i in range(2**n)]\n",
"\n",
" # Ensure each element has length n (pad with leading zeros if necessary)\n",
" for i in range(len(gf)):\n",
" if len(gf[i]) < n:\n",
" gf[i] = \"0\" * (n - len(gf[i])) + gf[i]\n",
"\n",
" # Create mappings: index -> element (key2ele) and element -> index (ele2key)\n",
" key2ele = dict(enumerate(gf))\n",
" ele2key = dict([i[::-1] for i in list(enumerate(gf))])\n",
"\n",
" # Generate the inverse map for all non-zero elements\n",
" invmap = dict()\n",
" for i in gf:\n",
" if set(i) != set(\"0\"): # Skip zero element\n",
" inv = bit2str(Gfinv(str2bit(i), irrpoly=irrpoly)) # Find the inverse of i\n",
<<<<<<< HEAD
" invmap[ele2key[i]] = ele2key[inv] # Map the inverse using element-to-key mapping\n",
" \n",
" return gf, invmap\n",
"# Example call\n",
"Gfinv([0, 0, 0, 0, 0, 1, 0, 0], irrpoly=[0, 0, 0, 1, 0, 0, 1, 1])\n"
=======
" invmap[ele2key[i]] = ele2key[\n",
" inv\n",
" ] # Map the inverse using element-to-key mapping\n",
"\n",
" return gf, invmap"
>>>>>>> ffbe3bbd8623bff453d16b942b7cf035c20d808c
]
},
{
"cell_type": "code",
"execution_count": 6,
"id": "d4ca99d5",
"metadata": {},
"outputs": [],
"source": [
"gf5, invmap = genmapping(n=5, irrpoly=id2bit([5, 2, 0]))"
]
},
{
"cell_type": "code",
"execution_count": 7,
"id": "44e4797e",
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"True"
]
},
"execution_count": 7,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"set(invmap.values()) == set(invmap.keys())"
]
},
{
"cell_type": "code",
"execution_count": 8,
"id": "b08bd2b6",
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"{1: 1,\n",
" 2: 18,\n",
" 3: 28,\n",
" 4: 9,\n",
" 5: 23,\n",
" 6: 14,\n",
" 7: 12,\n",
" 8: 22,\n",
" 9: 4,\n",
" 10: 25,\n",
" 11: 16,\n",
" 12: 7,\n",
" 13: 15,\n",
" 14: 6,\n",
" 15: 13,\n",
" 16: 11,\n",
" 17: 24,\n",
" 18: 2,\n",
" 19: 29,\n",
" 20: 30,\n",
" 21: 26,\n",
" 22: 8,\n",
" 23: 5,\n",
" 24: 17,\n",
" 25: 10,\n",
" 26: 21,\n",
" 27: 31,\n",
" 28: 3,\n",
" 29: 19,\n",
" 30: 20,\n",
" 31: 27}"
]
},
"execution_count": 8,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"invmap"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "90374ee9",
"metadata": {},
"outputs": [],
"source": []
},
{
"cell_type": "code",
"execution_count": 9,
"id": "06a7f472",
"metadata": {},
"outputs": [],
"source": [
"gf28 = [str(bin(i))[2:] for i in range(256)]\n",
"for i in range(len(gf28)):\n",
" if len(gf28[i]) < 8:\n",
" gf28[i] = \"0\" * (8 - len(gf28[i])) + gf28[i]\n",
"\n",
"key2ele = dict(enumerate(gf28))\n",
"ele2key = dict([i[::-1] for i in list(enumerate(gf28))])\n",
"invmap = dict()\n",
"for i in gf28:\n",
" if set(i) != set(\"0\"):\n",
" inv = bit2str(Gfinv(str2bit(i)))\n",
" invmap[ele2key[i]] = ele2key[inv]"
]
},
{
"cell_type": "code",
"execution_count": 10,
"id": "5fcfedd5",
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"True"
]
},
"execution_count": 10,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"set(invmap.values()) == set(invmap.keys())"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "4059dff6",
"metadata": {},
"outputs": [],
"source": []
},
{
"cell_type": "code",
"execution_count": null,
"id": "06b3e5d5",
"metadata": {},
"outputs": [],
"source": []
},
{
"cell_type": "code",
"execution_count": null,
"id": "37dd903a",
"metadata": {},
"outputs": [],
"source": []
}
],
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