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/*
`MD5` hash algorithm.
WARNING: The MD5 algorithm is known to be insecure and should only be
used for interoperating with legacy applications.
See:
- [[ https://eprint.iacr.org/2005/075 ]]
- [[ https://datatracker.ietf.org/doc/html/rfc1321 ]]
*/
package md5
/*
Copyright 2021 zhibog
Made available under Odin's license.
List of contributors:
zhibog, dotbmp: Initial implementation.
*/
import "core:encoding/endian"
import "core:math/bits"
import "core:mem"
// DIGEST_SIZE is the MD5 digest size in bytes.
DIGEST_SIZE :: 16
// BLOCK_SIZE is the MD5 block size in bytes.
BLOCK_SIZE :: 64
// Context is a MD5 instance.
Context :: struct {
data: [BLOCK_SIZE]byte,
state: [4]u32,
bitlen: u64,
datalen: u32,
is_initialized: bool,
}
// init initializes a Context.
init :: proc(ctx: ^Context) {
ctx.state[0] = 0x67452301
ctx.state[1] = 0xefcdab89
ctx.state[2] = 0x98badcfe
ctx.state[3] = 0x10325476
ctx.bitlen = 0
ctx.datalen = 0
ctx.is_initialized = true
}
// update adds more data to the Context.
update :: proc(ctx: ^Context, data: []byte) {
ensure(ctx.is_initialized)
for i := 0; i < len(data); i += 1 {
ctx.data[ctx.datalen] = data[i]
ctx.datalen += 1
if (ctx.datalen == BLOCK_SIZE) {
transform(ctx, ctx.data[:])
ctx.bitlen += 512
ctx.datalen = 0
}
}
}
// final finalizes the Context, writes the digest to hash, and calls
// reset on the Context.
//
// Iff finalize_clone is set, final will work on a copy of the Context,
// which is useful for for calculating rolling digests.
final :: proc(ctx: ^Context, hash: []byte, finalize_clone: bool = false) {
ensure(ctx.is_initialized)
ensure(len(hash) >= DIGEST_SIZE, "crypto/md5: invalid destination digest size")
ctx := ctx
if finalize_clone {
tmp_ctx: Context
clone(&tmp_ctx, ctx)
ctx = &tmp_ctx
}
defer(reset(ctx))
i := ctx.datalen
if ctx.datalen < 56 {
ctx.data[i] = 0x80
i += 1
for i < 56 {
ctx.data[i] = 0x00
i += 1
}
} else if ctx.datalen >= 56 {
ctx.data[i] = 0x80
i += 1
for i < BLOCK_SIZE {
ctx.data[i] = 0x00
i += 1
}
transform(ctx, ctx.data[:])
mem.set(&ctx.data, 0, 56)
}
ctx.bitlen += u64(ctx.datalen * 8)
endian.unchecked_put_u64le(ctx.data[56:], ctx.bitlen)
transform(ctx, ctx.data[:])
for i = 0; i < DIGEST_SIZE / 4; i += 1 {
endian.unchecked_put_u32le(hash[i * 4:], ctx.state[i])
}
}
// clone clones the Context other into ctx.
clone :: proc(ctx, other: ^$T) {
ctx^ = other^
}
// reset sanitizes the Context. The Context must be re-initialized to
// be used again.
reset :: proc(ctx: ^$T) {
if !ctx.is_initialized {
return
}
mem.zero_explicit(ctx, size_of(ctx^))
}
/*
MD5 implementation
*/
/*
@note(zh): F, G, H and I, as mentioned in the RFC, have been inlined into FF, GG, HH
and II respectively, instead of declaring them separately.
*/
@(private)
FF :: #force_inline proc "contextless" (a, b, c, d, m: u32, s: int, t: u32) -> u32 {
return b + bits.rotate_left32(a + ((b & c) | (~b & d)) + m + t, s)
}
@(private)
GG :: #force_inline proc "contextless" (a, b, c, d, m: u32, s: int, t: u32) -> u32 {
return b + bits.rotate_left32(a + ((b & d) | (c & ~d)) + m + t, s)
}
@(private)
HH :: #force_inline proc "contextless" (a, b, c, d, m: u32, s: int, t: u32) -> u32 {
return b + bits.rotate_left32(a + (b ~ c ~ d) + m + t, s)
}
@(private)
II :: #force_inline proc "contextless" (a, b, c, d, m: u32, s: int, t: u32) -> u32 {
return b + bits.rotate_left32(a + (c ~ (b | ~d)) + m + t, s)
}
@(private)
transform :: proc "contextless" (ctx: ^Context, data: []byte) {
m: [DIGEST_SIZE]u32
for i := 0; i < DIGEST_SIZE; i += 1 {
m[i] = endian.unchecked_get_u32le(data[i * 4:])
}
a := ctx.state[0]
b := ctx.state[1]
c := ctx.state[2]
d := ctx.state[3]
a = FF(a, b, c, d, m[0], 7, 0xd76aa478)
d = FF(d, a, b, c, m[1], 12, 0xe8c7b756)
c = FF(c, d, a, b, m[2], 17, 0x242070db)
b = FF(b, c, d, a, m[3], 22, 0xc1bdceee)
a = FF(a, b, c, d, m[4], 7, 0xf57c0faf)
d = FF(d, a, b, c, m[5], 12, 0x4787c62a)
c = FF(c, d, a, b, m[6], 17, 0xa8304613)
b = FF(b, c, d, a, m[7], 22, 0xfd469501)
a = FF(a, b, c, d, m[8], 7, 0x698098d8)
d = FF(d, a, b, c, m[9], 12, 0x8b44f7af)
c = FF(c, d, a, b, m[10], 17, 0xffff5bb1)
b = FF(b, c, d, a, m[11], 22, 0x895cd7be)
a = FF(a, b, c, d, m[12], 7, 0x6b901122)
d = FF(d, a, b, c, m[13], 12, 0xfd987193)
c = FF(c, d, a, b, m[14], 17, 0xa679438e)
b = FF(b, c, d, a, m[15], 22, 0x49b40821)
a = GG(a, b, c, d, m[1], 5, 0xf61e2562)
d = GG(d, a, b, c, m[6], 9, 0xc040b340)
c = GG(c, d, a, b, m[11], 14, 0x265e5a51)
b = GG(b, c, d, a, m[0], 20, 0xe9b6c7aa)
a = GG(a, b, c, d, m[5], 5, 0xd62f105d)
d = GG(d, a, b, c, m[10], 9, 0x02441453)
c = GG(c, d, a, b, m[15], 14, 0xd8a1e681)
b = GG(b, c, d, a, m[4], 20, 0xe7d3fbc8)
a = GG(a, b, c, d, m[9], 5, 0x21e1cde6)
d = GG(d, a, b, c, m[14], 9, 0xc33707d6)
c = GG(c, d, a, b, m[3], 14, 0xf4d50d87)
b = GG(b, c, d, a, m[8], 20, 0x455a14ed)
a = GG(a, b, c, d, m[13], 5, 0xa9e3e905)
d = GG(d, a, b, c, m[2], 9, 0xfcefa3f8)
c = GG(c, d, a, b, m[7], 14, 0x676f02d9)
b = GG(b, c, d, a, m[12], 20, 0x8d2a4c8a)
a = HH(a, b, c, d, m[5], 4, 0xfffa3942)
d = HH(d, a, b, c, m[8], 11, 0x8771f681)
c = HH(c, d, a, b, m[11], 16, 0x6d9d6122)
b = HH(b, c, d, a, m[14], 23, 0xfde5380c)
a = HH(a, b, c, d, m[1], 4, 0xa4beea44)
d = HH(d, a, b, c, m[4], 11, 0x4bdecfa9)
c = HH(c, d, a, b, m[7], 16, 0xf6bb4b60)
b = HH(b, c, d, a, m[10], 23, 0xbebfbc70)
a = HH(a, b, c, d, m[13], 4, 0x289b7ec6)
d = HH(d, a, b, c, m[0], 11, 0xeaa127fa)
c = HH(c, d, a, b, m[3], 16, 0xd4ef3085)
b = HH(b, c, d, a, m[6], 23, 0x04881d05)
a = HH(a, b, c, d, m[9], 4, 0xd9d4d039)
d = HH(d, a, b, c, m[12], 11, 0xe6db99e5)
c = HH(c, d, a, b, m[15], 16, 0x1fa27cf8)
b = HH(b, c, d, a, m[2], 23, 0xc4ac5665)
a = II(a, b, c, d, m[0], 6, 0xf4292244)
d = II(d, a, b, c, m[7], 10, 0x432aff97)
c = II(c, d, a, b, m[14], 15, 0xab9423a7)
b = II(b, c, d, a, m[5], 21, 0xfc93a039)
a = II(a, b, c, d, m[12], 6, 0x655b59c3)
d = II(d, a, b, c, m[3], 10, 0x8f0ccc92)
c = II(c, d, a, b, m[10], 15, 0xffeff47d)
b = II(b, c, d, a, m[1], 21, 0x85845dd1)
a = II(a, b, c, d, m[8], 6, 0x6fa87e4f)
d = II(d, a, b, c, m[15], 10, 0xfe2ce6e0)
c = II(c, d, a, b, m[6], 15, 0xa3014314)
b = II(b, c, d, a, m[13], 21, 0x4e0811a1)
a = II(a, b, c, d, m[4], 6, 0xf7537e82)
d = II(d, a, b, c, m[11], 10, 0xbd3af235)
c = II(c, d, a, b, m[2], 15, 0x2ad7d2bb)
b = II(b, c, d, a, m[9], 21, 0xeb86d391)
ctx.state[0] += a
ctx.state[1] += b
ctx.state[2] += c
ctx.state[3] += d
}
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