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"source": [
"# Table of Contents\n",
" "
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"metadata": {},
"source": [
"# Implementing the ChaCha Pseudo-Random Number Generator (PNRG) in Julia\n",
"\n",
"- This post is inspired by [this recent blog post by John D. Cook](https://www.johndcook.com/blog/2019/03/03/do-the-chacha/),\n",
"- The reference is the official reference, the [RFC-8439](https://tools.ietf.org/html/rfc8439),\n",
"- Author: [Lilian Besson](https://github.com/Naereen),\n",
"- License: [MIT License](https://lbesson.mit-license.org/)\n",
"- Date: 4th of March, 2019."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Implementation"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Preliminary functions"
]
},
{
"cell_type": "code",
"execution_count": 30,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"(4294967296, 4294967296, 4294967296)"
]
},
"execution_count": 30,
"metadata": {},
"output_type": "execute_result"
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"source": [
"2 ^ 32, 1 << 32, 2 << 31"
]
},
{
"cell_type": "code",
"execution_count": 10,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
" 0.000010 seconds (5 allocations: 176 bytes)\n",
" 0.000127 seconds (5 allocations: 176 bytes)\n"
]
},
{
"data": {
"text/plain": [
"2147483648"
]
},
"execution_count": 10,
"metadata": {},
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"source": [
"@time 1 << 31\n",
"@time 2 ^ 31"
]
},
{
"cell_type": "code",
"execution_count": 37,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"roll (generic function with 1 method)"
]
},
"execution_count": 37,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"function roll(x, n)\n",
" return (x << n) % (1 << 32) + (x >> (32 - n))\n",
"end"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"We can test our operation:"
]
},
{
"cell_type": "code",
"execution_count": 39,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"2023406814\n",
"2023406814\n",
"2040053722\n",
"2040053722\n",
"3428838716\n",
"3428838716\n"
]
}
],
"source": [
"a = 0x11111111\n",
"b = 0x01020304\n",
"c = 0x77777777\n",
"d = 0x01234567\n",
"println(c + d)\n",
"println(0x789abcde)\n",
"c = c + d\n",
"println(xor(b, c))\n",
"println(0x7998bfda)\n",
"b = xor(b, c)\n",
"println(roll(b, 7))\n",
"println(0xcc5fed3c)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Now the \"quarter round\" is implemented like this:"
]
},
{
"cell_type": "code",
"execution_count": 48,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"quarter_round (generic function with 2 methods)"
]
},
"execution_count": 48,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"function quarter_round(a, b, c, d)\n",
" a = (a + b) % (1 << 32)\n",
" d = roll(xor(d, a), 16)\n",
" c = (c + d) % (1 << 32)\n",
" b = roll(xor(b, c), 12)\n",
" a = (a + b) % (1 << 32)\n",
" d = roll(xor(d, a), 8)\n",
" c = (c + d) % (1 << 32)\n",
" b = roll(xor(b, c), 7)\n",
" return a, b, c, d\n",
"end"
]
},
{
"cell_type": "code",
"execution_count": 49,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"(0x00000000ea2a92f4, 0x00000000cb1cf8ce, 0x000000004581472e, 0x000000005881c4bb)"
]
},
"execution_count": 49,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"a = 0x11111111\n",
"b = 0x01020304\n",
"c = 0x9b8d6f43\n",
"d = 0x01234567\n",
"\n",
"quarter_round(a, b, c, d)"
]
},
{
"cell_type": "code",
"execution_count": 50,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"UInt32"
]
},
"execution_count": 50,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"typeof(a)"
]
},
{
"cell_type": "code",
"execution_count": 51,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"(0xea2a92f4, 0xcb1cf8ce, 0x4581472e, 0x5881c4bb)"
]
},
"execution_count": 51,
"metadata": {},
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"source": [
"0xea2a92f4, 0xcb1cf8ce, 0x4581472e, 0x5881c4bb"
]
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{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Examples"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": []
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": []
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": []
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Tests"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": []
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": []
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": []
}
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