#
#
# Nim's Runtime Library
# (c) Copyright 2010 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## Module for computing MD5 checksums.
type
MD5State = array[0..3, uint32]
MD5Block = array[0..15, uint32]
MD5CBits = array[0..7, uint8]
MD5Digest* = array[0..15, uint8]
MD5Buffer = array[0..63, uint8]
MD5Context* {.final.} = object
state: MD5State
count: array[0..1, uint32]
buffer: MD5Buffer
const
padding: cstring = "\x80\0\0\0" &
"\0\0\0\0\0\0\0\0" &
"\0\0\0\0\0\0\0\0" &
"\0\0\0\0\0\0\0\0" &
"\0\0\0\0\0\0\0\0" &
"\0\0\0\0\0\0\0\0" &
"\0\0\0\0\0\0\0\0" &
"\0\0\0\0\0\0\0\0" &
"\0\0\0\0"
proc F(x, y, z: uint32): uint32 {.inline.} =
result = (x and y) or ((not x) and z)
proc G(x, y, z: uint32): uint32 {.inline.} =
result = (x and z) or (y and (not z))
proc H(x, y, z: uint32): uint32 {.inline.} =
result = x xor y xor z
proc I(x, y, z: uint32): uint32 {.inline.} =
result = y xor (x or (not z))
proc rot(x: var uint32, n: uint8) {.inline.} =
x = (x shl n) or (x shr (32'u32 - n))
proc FF(a: var uint32, b, c, d, x: uint32, s: uint8, ac: uint32) =
a = a + F(b, c, d) + x + ac
rot(a, s)
a = a + b
proc GG(a: var uint32, b, c, d, x: uint32, s: uint8, ac: uint32) =
a = a + G(b, c, d) + x + ac
rot(a, s)
a = a + b
proc HH(a: var uint32, b, c, d, x: uint32, s: uint8, ac: uint32) =
a = a + H(b, c, d) + x + ac
rot(a, s)
a = a + b
proc II(a: var uint32, b, c, d, x: uint32, s: uint8, ac: uint32) =
a = a + I(b, c, d) + x + ac
rot(a, s)
a = a + b
proc encode(dest: var MD5Block, src: cstring) =
var j = 0
for i in 0..high(dest):
dest[i] = uint32(ord(src[j])) or
uint32(ord(src[j+1])) shl 8 or
uint32(ord(src[j+2])) shl 16 or
uint32(ord(src[j+3])) shl 24
inc(j, 4)
proc decode(dest: var openArray[uint8], src: openArray[uint32]) =
var i = 0
for j in 0..high(src):
dest[i] = src[j] and 0xff'u32
dest[i+1] = src[j] shr 8 and 0xff'u32
dest[i+2] = src[j] shr 16 and 0xff'u32
dest[i+3] = src[j] shr 24 and 0xff'u32
inc(i, 4)
proc transform(buffer: pointer, state: var MD5State) =
var
myBlock: MD5Block
encode(myBlock, cast[cstring](buffer))
var a = state[0]
var b = state[1]
var c = state[2]
var d = state[3]
FF(a, b, c, d, myBlock[0], 7'u8, 0xD76AA478'u32)
FF(d, a, b, c, myBlock[1], 12'u8, 0xE8C7B756'u32)
FF(c, d, a, b, myBlock[2], 17'u8, 0x242070DB'u32)
FF(b, c, d, a, myBlock[3], 22'u8, 0xC1BDCEEE'u32)
FF(a, b, c, d, myBlock[4], 7'u8, 0xF57C0FAF'u32)
FF(d, a, b, c, myBlock[5], 12'u8, 0x4787C62A'u32)
FF(c, d, a, b, myBlock[6], 17'u8, 0xA8304613'u32)
FF(b, c, d, a, myBlock[7], 22'u8, 0xFD469501'u32)
FF(a, b, c, d, myBlock[8], 7'u8, 0x698098D8'u32)
FF(d, a, b, c, myBlock[9], 12'u8, 0x8B44F7AF'u32)
FF(c, d, a, b, myBlock[10], 17'u8, 0xFFFF5BB1'u32)
FF(b, c, d, a, myBlock[11], 22'u8, 0x895CD7BE'u32)
FF(a, b, c, d, myBlock[12], 7'u8, 0x6B901122'u32)
FF(d, a, b, c, myBlock[13], 12'u8, 0xFD987193'u32)
FF(c, d, a, b, myBlock[14], 17'u8, 0xA679438E'u32)
FF(b, c, d, a, myBlock[15], 22'u8, 0x49B40821'u32)
GG(a, b, c, d, myBlock[1], 5'u8, 0xF61E2562'u32)
GG(d, a, b, c, myBlock[6], 9'u8, 0xC040B340'u32)
GG(c, d, a, b, myBlock[11], 14'u8, 0x265E5A51'u32)
GG(b, c, d, a, myBlock[0], 20'u8, 0xE9B6C7AA'u32)
GG(a, b, c, d, myBlock[5], 5'u8, 0xD62F105D'u32)
GG(d, a, b, c, myBlock[10], 9'u8, 0x02441453'u32)
GG(c, d, a, b, myBlock[15], 14'u8, 0xD8A1E681'u32)
GG(b, c, d, a, myBlock[4], 20'u8, 0xE7D3FBC8'u32)
GG(a, b, c, d, myBlock[9], 5'u8, 0x21E1CDE6'u32)
GG(d, a, b, c, myBlock[14], 9'u8, 0xC33707D6'u32)
GG(c, d, a, b, myBlock[3], 14'u8, 0xF4D50D87'u32)
GG(b, c, d, a, myBlock[8], 20'u8, 0x455A14ED'u32)
GG(a, b, c, d, myBlock[13], 5'u8, 0xA9E3E905'u32)
GG(d, a, b, c, myBlock[2], 9'u8, 0xFCEFA3F8'u32)
GG(c, d, a, b, myBlock[7], 14'u8, 0x676F02D9'u32)
GG(b, c, d, a, myBlock[12], 20'u8, 0x8D2A4C8A'u32)
HH(a, b, c, d, myBlock[5], 4'u8, 0xFFFA3942'u32)
HH(d, a, b, c, myBlock[8], 11'u8, 0x8771F681'u32)
HH(c, d, a, b, myBlock[11], 16'u8, 0x6D9D6122'u32)
HH(b, c, d, a, myBlock[14], 23'u8, 0xFDE5380C'u32)
HH(a, b, c, d, myBlock[1], 4'u8, 0xA4BEEA44'u32)
HH(d, a, b, c, myBlock[4], 11'u8, 0x4BDECFA9'u32)
HH(c, d, a, b, myBlock[7], 16'u8, 0xF6BB4B60'u32)
HH(b, c, d, a, myBlock[10], 23'u8, 0xBEBFBC70'u32)
HH(a, b, c, d, myBlock[13], 4'u8, 0x289B7EC6'u32)
HH(d, a, b, c, myBlock[0], 11'u8, 0xEAA127FA'u32)
HH(c, d, a, b, myBlock[3], 16'u8, 0xD4EF3085'u32)
HH(b, c, d, a, myBlock[6], 23'u8, 0x04881D05'u32)
HH(a, b, c, d, myBlock[9], 4'u8, 0xD9D4D039'u32)
HH(d, a, b, c, myBlock[12], 11'u8, 0xE6DB99E5'u32)
HH(c, d, a, b, myBlock[15], 16'u8, 0x1FA27CF8'u32)
HH(b, c, d, a, myBlock[2], 23'u8, 0xC4AC5665'u32)
II(a, b, c, d, myBlock[0], 6'u8, 0xF4292244'u32)
II(d, a, b, c, myBlock[7], 10'u8, 0x432AFF97'u32)
II(c, d, a, b, myBlock[14], 15'u8, 0xAB9423A7'u32)
II(b, c, d, a, myBlock[5], 21'u8, 0xFC93A039'u32)
II(a, b, c, d, myBlock[12], 6'u8, 0x655B59C3'u32)
II(d, a, b, c, myBlock[3], 10'u8, 0x8F0CCC92'u32)
II(c, d, a, b, myBlock[10], 15'u8, 0xFFEFF47D'u32)
II(b, c, d, a, myBlock[1], 21'u8, 0x85845DD1'u32)
II(a, b, c, d, myBlock[8], 6'u8, 0x6FA87E4F'u32)
II(d, a, b, c, myBlock[15], 10'u8, 0xFE2CE6E0'u32)
II(c, d, a, b, myBlock[6], 15'u8, 0xA3014314'u32)
II(b, c, d, a, myBlock[13], 21'u8, 0x4E0811A1'u32)
II(a, b, c, d, myBlock[4], 6'u8, 0xF7537E82'u32)
II(d, a, b, c, myBlock[11], 10'u8, 0xBD3AF235'u32)
II(c, d, a, b, myBlock[2], 15'u8, 0x2AD7D2BB'u32)
II(b, c, d, a, myBlock[9], 21'u8, 0xEB86D391'u32)
state[0] = state[0] + a
state[1] = state[1] + b
state[2] = state[2] + c
state[3] = state[3] + d
proc md5Init*(c: var MD5Context) =
## initializes a MD5Context
c.state[0] = 0x67452301'u32
c.state[1] = 0xEFCDAB89'u32
c.state[2] = 0x98BADCFE'u32
c.state[3] = 0x10325476'u32
c.count[0] = 0'u32
c.count[1] = 0'u32
zeroMem(addr(c.buffer), sizeof(MD5buffer))
proc md5Update*(c: var MD5Context, input: cstring, len: int) =
## updates the MD5Context with the `input` data of length `len`
var input = input
var Index = int((c.count[0] shr 3) and 0x3F)
c.count[0] = c.count[0] + (uint32(len) shl 3)
if c.count[0] < (uint32(len) shl 3): c.count[1] = c.count[1] + 1'u32
c.count[1] = c.count[1] + (uint32(len) shr 29)
var PartLen = 64 - Index
if len >= PartLen:
copyMem(addr(c.buffer[Index]), input, PartLen)
transform(addr(c.buffer), c.state)
var i = PartLen
while i + 63 < len:
transform(addr(input[i]), c.state)
inc(i, 64)
copyMem(addr(c.buffer[0]), addr(input[i]), len-i)
else:
copyMem(addr(c.buffer[Index]), addr(input[0]), len)
proc md5Final*(c: var MD5Context, digest: var MD5Digest) =
## finishes the MD5Context and stores the result in `digest`
var
Bits: MD5CBits
PadLen: int
decode(Bits, c.count)
var Index = int((c.count[0] shr 3) and 0x3F)
if Index < 56: PadLen = 56 - Index
else: PadLen = 120 - Index
md5Update(c, padding, PadLen)
md5Update(c, cast[cstring](addr(Bits)), 8)
decode(digest, c.state)
zeroMem(addr(c), sizeof(MD5Context))
proc toMD5*(s: string): MD5Digest =
## computes the MD5Digest value for a string `s`
var c: MD5Context
md5Init(c)
md5Update(c, cstring(s), len(s))
md5Final(c, result)
proc `$`*(d: MD5Digest): string =
## converts a MD5Digest value into its string representation
const digits = "0123456789abcdef"
result = ""
for i in 0..15:
add(result, digits[(d[i] shr 4) and 0xF])
add(result, digits[d[i] and 0xF])
proc getMD5*(s: string): string =
## computes an MD5 value of `s` and returns its string representation
var
c: MD5Context
d: MD5Digest
md5Init(c)
md5Update(c, cstring(s), len(s))
md5Final(c, d)
result = $d
proc `==`*(D1, D2: MD5Digest): bool =
## checks if two MD5Digest values are identical
for i in 0..15:
if D1[i] != D2[i]: return false
return true
when isMainModule:
assert(getMD5("Franz jagt im komplett verwahrlosten Taxi quer durch Bayern") ==
"a3cca2b2aa1e3b5b3b5aad99a8529074")
assert(getMD5("Frank jagt im komplett verwahrlosten Taxi quer durch Bayern") ==
"7e716d0e702df0505fc72e2b89467910")
assert($toMD5("") == "d41d8cd98f00b204e9800998ecf8427e")