commit 4eb513847412ece32ce164eda78b884d53f3562d
parent 9c75c05dd658664db57cb1cda07dacbb6ed8aca7
Author: erai <erai@omiltem.net>
Date: Wed, 8 May 2024 20:42:41 -0400
Add chacha20
Diffstat:
| A | chacha20.c | | | 200 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
| A | chacha20_test.c | | | 49 | +++++++++++++++++++++++++++++++++++++++++++++++++ |
2 files changed, 249 insertions(+), 0 deletions(-)
diff --git a/chacha20.c b/chacha20.c
@@ -0,0 +1,200 @@
+// https://www.rfc-editor.org/rfc/rfc7539
+
+struct _chacha20_state {
+ s0: int;
+ s1: int;
+ s2: int;
+ s3: int;
+ s4: int;
+ s5: int;
+ s6: int;
+ s7: int;
+ s8: int;
+ s9: int;
+ s10: int;
+ s11: int;
+ s12: int;
+ s13: int;
+ s14: int;
+ s15: int;
+}
+
+rol32(x: int, n: int): int {
+ return ((x << n) | (x >> (32 - n))) & (-1 >> 32);
+}
+
+chacha20_qround(a: *int, b: *int, c: *int, d: *int) {
+ *a = (*a + *b) & (-1 >> 32);
+ *d = (*d ^ *a) & (-1 >> 32);
+ *d = rol32(*d, 16);
+
+ *c = (*c + *d) & (-1 >> 32);
+ *b = (*b ^ *c) & (-1 >> 32);
+ *b = rol32(*b, 12);
+
+ *a = (*a + *b) & (-1 >> 32);
+ *d = (*d ^ *a) & (-1 >> 32);
+ *d = rol32(*d, 8);
+
+ *c = (*c + *d) & (-1 >> 32);
+ *b = (*b ^ *c) & (-1 >> 32);
+ *b = rol32(*b, 7);
+}
+
+chacha20_block(block: *byte, key: *byte, counter: int, nonce: *byte) {
+ var _initial: _chacha20_state;
+ var initial: *int;
+ var _s: _chacha20_state;
+ var s: *int;
+ var i: int;
+
+ initial = (&_initial):*int;
+ s = (&_s):*int;
+
+ s[0] = 0x61707865;
+ s[1] = 0x3320646e;
+ s[2] = 0x79622d32;
+ s[3] = 0x6b206574;
+
+ s[4] = key[0]:int
+ | (key[1]:int << 8)
+ | (key[2]:int << 16)
+ | (key[3]:int << 24);
+ s[5] = key[4]:int
+ | (key[5]:int << 8)
+ | (key[6]:int << 16)
+ | (key[7]:int << 24);
+ s[6] = key[8]:int
+ | (key[9]:int << 8)
+ | (key[10]:int << 16)
+ | (key[11]:int << 24);
+ s[7] = key[12]:int
+ | (key[13]:int << 8)
+ | (key[14]:int << 16)
+ | (key[15]:int << 24);
+ s[8] = key[16]:int
+ | (key[17]:int << 8)
+ | (key[18]:int << 16)
+ | (key[19]:int << 24);
+ s[9] = key[20]:int
+ | (key[21]:int << 8)
+ | (key[22]:int << 16)
+ | (key[23]:int << 24);
+ s[10] = key[24]:int
+ | (key[25]:int << 8)
+ | (key[26]:int << 16)
+ | (key[27]:int << 24);
+ s[11] = key[28]:int
+ | (key[29]:int << 8)
+ | (key[30]:int << 16)
+ | (key[31]:int << 24);
+
+ s[12] = counter & (-1 >> 32);
+
+ s[13] = nonce[0]:int
+ | (nonce[1]:int << 8)
+ | (nonce[2]:int << 16)
+ | (nonce[3]:int << 24);
+ s[14] = nonce[4]:int
+ | (nonce[5]:int << 8)
+ | (nonce[6]:int << 16)
+ | (nonce[7]:int << 24);
+ s[15] = nonce[8]:int
+ | (nonce[9]:int << 8)
+ | (nonce[10]:int << 16)
+ | (nonce[11]:int << 24);
+
+ i = 0;
+ loop {
+ if i == 16 {
+ break;
+ }
+ initial[i] = s[i];
+ i = i + 1;
+ }
+
+ i = 0;
+ loop {
+ if i == 10 {
+ break;
+ }
+ chacha20_qround(&s[0], &s[4], &s[8], &s[12]);
+ chacha20_qround(&s[1], &s[5], &s[9], &s[13]);
+ chacha20_qround(&s[2], &s[6], &s[10], &s[14]);
+ chacha20_qround(&s[3], &s[7], &s[11], &s[15]);
+ chacha20_qround(&s[0], &s[5], &s[10], &s[15]);
+ chacha20_qround(&s[1], &s[6], &s[11], &s[12]);
+ chacha20_qround(&s[2], &s[7], &s[8], &s[13]);
+ chacha20_qround(&s[3], &s[4], &s[9], &s[14]);
+ i = i + 1;
+ }
+
+ i = 0;
+ loop {
+ if i == 16 {
+ break;
+ }
+ s[i] = (s[i] + initial[i]) & (-1 >> 32);
+ i = i + 1;
+ }
+
+ i = 0;
+ loop {
+ if i == 16 {
+ break;
+ }
+ block[i * 4] = s[i]:byte;
+ block[i * 4 + 1] = (s[i] >> 8):byte;
+ block[i * 4 + 2] = (s[i] >> 16):byte;
+ block[i * 4 + 3] = (s[i] >> 24):byte;
+ i = i + 1;
+ }
+}
+
+chacha20_stream(cipher: *byte, plain: *byte, len: int, index: *int, key: *byte, nonce: *byte) {
+ var _block: _chacha20_state;
+ var block: *byte;
+ var i: int;
+ var j: int;
+
+ j = 0;
+ i = index[0] & 63;
+
+ if i {
+ chacha20_block(block, key, index[0] >> 6, nonce);
+
+ loop {
+ if j == len || i == 64 {
+ break;
+ }
+
+ cipher[j] = plain[j] ^ block[i];
+
+ index[0] = index[0] + 1;
+ i = i + 1;
+ j = j + 1;
+ }
+ }
+
+ loop {
+ if j == len {
+ break;
+ }
+
+ chacha20_block(block, key, index[0] >> 6, nonce);
+
+ i = 0;
+ loop {
+ if j == len || i == 64 {
+ break;
+ }
+
+ cipher[j] = plain[j] ^ block[j];
+
+ i = i + 1;
+ j = j + 1;
+ }
+
+ index[0] = index[0] + 64;
+ }
+}
diff --git a/chacha20_test.c b/chacha20_test.c
@@ -0,0 +1,49 @@
+main(c:int,v:**byte,e:**byte) {
+ var _key: _chacha20_state;
+ var key: *byte;
+ var _nonce: _chacha20_state;
+ var nonce: *byte;
+ var _block: _chacha20_state;
+ var block: *byte;
+
+ key = (&_key):*byte;
+ nonce = (&_nonce):*byte;
+ block = (&_block):*byte;
+
+ bzero(key, sizeof(_key));
+ bzero(nonce, sizeof(_nonce));
+
+ chacha20_block(block, key, 0, nonce);
+ fdputd(1, 1);
+ fdputs(1, ":\n");
+ fdxxd(1, block, 64);
+ fdputc(1, '\n');
+
+ chacha20_block(block, key, 1, nonce);
+ fdputd(1, 2);
+ fdputs(1, ":\n");
+ fdxxd(1, block, 64);
+ fdputc(1, '\n');
+
+ key[31] = 1:byte;
+ chacha20_block(block, key, 1, nonce);
+ fdputd(1, 3);
+ fdputs(1, ":\n");
+ fdxxd(1, block, 64);
+ fdputc(1, '\n');
+
+ key[1] = 0xff:byte;
+ key[31] = 0:byte;
+ chacha20_block(block, key, 2, nonce);
+ fdputd(1, 4);
+ fdputs(1, ":\n");
+ fdxxd(1, block, 64);
+ fdputc(1, '\n');
+
+ key[1] = 0:byte;
+ nonce[11] = 2:byte;
+ chacha20_block(block, key, 0, nonce);
+ fdputd(1, 5);
+ fdputs(1, ":\n");
+ fdxxd(1, block, 64);
+}
