Implemented MD5 in Crystal

src/crypto/md5.cr

@@ -1,18 +1,255 @@
-require "openssl/md5"
-
 class Crypto::MD5
   def self.hex_digest(data : String)
-    hash = OpenSSL::MD5.hash(data)
-    hash_str = String.new(32) do |buffer|
-      0.upto(15) do |i|
-        buffer[i * 2] = to_hex((hash[i]) >> 4)
-        buffer[i * 2 + 1] = to_hex(hash[i] & 0x0f)
+    context = Context.new
+    context.update(data.to_unsafe, data.bytesize.to_u32)
+    context.final
+    context.hex
+  end
+
+  struct Context
+    def initialize
+      @i = StaticArray(UInt32, 2).new(0_u32)
+      @buf = StaticArray(UInt32, 4).new(0_u32)
+      @buf[0] = 0x67452301_u32
+      @buf[1] = 0xEFCDAB89_u32
+      @buf[2] = 0x98BADCFE_u32
+      @buf[3] = 0x10325476_u32
+      @in = StaticArray(UInt8, 64).new(0_u8)
+      @digest :: UInt8[16]
+    end
+
+    def update(inBuf, inLen)
+      in :: UInt32[16]
+
+      # compute number of bytes mod 64
+      mdi = (@i[0] >> 3) & 0x3F
+
+      # update number of bits
+      @i[1] += 1 if (@i[0] + (inLen << 3)) < @i[0]
+      @i[0] += (inLen << 3)
+      @i[1] += (inLen >> 29)
+
+      inLen.times do
+        # add new character to buffer, increment mdi
+        @in[mdi] = inBuf.value
+        mdi += 1
+        inBuf += 1
+
+        # transform if necessary
+        if mdi == 0x40
+          ii = 0
+          16.times do |i|
+            in[i] = (@in[ii+3].to_u32 << 24) |
+                    (@in[ii+2].to_u32 << 16) |
+                    (@in[ii+1].to_u32 << 8)  |
+                    (@in[ii])
+            ii += 4
+          end
+          transform in
+          mdi = 0
+        end
       end
-      {32, 32}
     end
-  end
 
-  private def self.to_hex(c)
-    ((c < 10 ? 48_u8 : 87_u8) + c)
+    S11 = 7
+    S12 = 12
+    S13 = 17
+    S14 = 22
+
+    S21 = 5
+    S22 = 9
+    S23 = 14
+    S24 = 20
+
+    S31 = 4
+    S32 = 11
+    S33 = 16
+    S34 = 23
+
+    S41 = 6
+    S42 = 10
+    S43 = 15
+    S44 = 21
+
+    PADDING = begin
+      padding = StaticArray(UInt8, 64).new(0_u8)
+      padding[0] = 0x80_u8
+      padding
+    end
+
+    def f(x, y, z)
+      (x & y) | ((~x) & z)
+    end
+
+    def g(x, y, z)
+      (x & z) | (y & (~z))
+    end
+
+    def h(x, y, z)
+      x ^ y ^ z
+    end
+
+    def i(x, y, z)
+      y ^ (x | (~z))
+    end
+
+    def rotate_left(x, n)
+      (x << n) | (x >> (32-n))
+    end
+
+    def ff(a, b, c, d, x, s, ac)
+      a += f(b, c, d) + x + ac.to_u32
+      a = rotate_left a, s
+      a += b
+    end
+
+    def gg(a, b, c, d, x, s, ac)
+      a += g(b, c, d) + x + ac.to_u32
+      a = rotate_left a, s
+      a += b
+    end
+
+    def hh(a, b, c, d, x, s, ac)
+      a += h(b, c, d) + x + ac.to_u32
+      a = rotate_left a, s
+      a += b
+    end
+
+    def ii(a, b, c, d, x, s, ac)
+      a += i(b, c, d) + x + ac.to_u32
+      a = rotate_left a, s
+      a += b
+    end
+
+    def transform(in)
+      a, b, c, d = @buf
+
+      # Round 1
+      a = ff( a, b, c, d, in[ 0], S11, 3614090360); # 1
+      d = ff( d, a, b, c, in[ 1], S12, 3905402710); # 2
+      c = ff( c, d, a, b, in[ 2], S13,  606105819); # 3
+      b = ff( b, c, d, a, in[ 3], S14, 3250441966); # 4
+      a = ff( a, b, c, d, in[ 4], S11, 4118548399); # 5
+      d = ff( d, a, b, c, in[ 5], S12, 1200080426); # 6
+      c = ff( c, d, a, b, in[ 6], S13, 2821735955); # 7
+      b = ff( b, c, d, a, in[ 7], S14, 4249261313); # 8
+      a = ff( a, b, c, d, in[ 8], S11, 1770035416); # 9
+      d = ff( d, a, b, c, in[ 9], S12, 2336552879); # 10
+      c = ff( c, d, a, b, in[10], S13, 4294925233); # 11
+      b = ff( b, c, d, a, in[11], S14, 2304563134); # 12
+      a = ff( a, b, c, d, in[12], S11, 1804603682); # 13
+      d = ff( d, a, b, c, in[13], S12, 4254626195); # 14
+      c = ff( c, d, a, b, in[14], S13, 2792965006); # 15
+      b = ff( b, c, d, a, in[15], S14, 1236535329); # 16
+
+      # Round 2
+      a = gg( a, b, c, d, in[ 1], S21, 4129170786); # 17
+      d = gg( d, a, b, c, in[ 6], S22, 3225465664); # 18
+      c = gg( c, d, a, b, in[11], S23,  643717713); # 19
+      b = gg( b, c, d, a, in[ 0], S24, 3921069994); # 20
+      a = gg( a, b, c, d, in[ 5], S21, 3593408605); # 21
+      d = gg( d, a, b, c, in[10], S22,   38016083); # 22
+      c = gg( c, d, a, b, in[15], S23, 3634488961); # 23
+      b = gg( b, c, d, a, in[ 4], S24, 3889429448); # 24
+      a = gg( a, b, c, d, in[ 9], S21,  568446438); # 25
+      d = gg( d, a, b, c, in[14], S22, 3275163606); # 26
+      c = gg( c, d, a, b, in[ 3], S23, 4107603335); # 27
+      b = gg( b, c, d, a, in[ 8], S24, 1163531501); # 28
+      a = gg( a, b, c, d, in[13], S21, 2850285829); # 29
+      d = gg( d, a, b, c, in[ 2], S22, 4243563512); # 30
+      c = gg( c, d, a, b, in[ 7], S23, 1735328473); # 31
+      b = gg( b, c, d, a, in[12], S24, 2368359562); # 32
+
+      # Round 3
+      a = hh( a, b, c, d, in[ 5], S31, 4294588738); # 33
+      d = hh( d, a, b, c, in[ 8], S32, 2272392833); # 34
+      c = hh( c, d, a, b, in[11], S33, 1839030562); # 35
+      b = hh( b, c, d, a, in[14], S34, 4259657740); # 36
+      a = hh( a, b, c, d, in[ 1], S31, 2763975236); # 37
+      d = hh( d, a, b, c, in[ 4], S32, 1272893353); # 38
+      c = hh( c, d, a, b, in[ 7], S33, 4139469664); # 39
+      b = hh( b, c, d, a, in[10], S34, 3200236656); # 40
+      a = hh( a, b, c, d, in[13], S31,  681279174); # 41
+      d = hh( d, a, b, c, in[ 0], S32, 3936430074); # 42
+      c = hh( c, d, a, b, in[ 3], S33, 3572445317); # 43
+      b = hh( b, c, d, a, in[ 6], S34,   76029189); # 44
+      a = hh( a, b, c, d, in[ 9], S31, 3654602809); # 45
+      d = hh( d, a, b, c, in[12], S32, 3873151461); # 46
+      c = hh( c, d, a, b, in[15], S33,  530742520); # 47
+      b = hh( b, c, d, a, in[ 2], S34, 3299628645); # 48
+
+      # Round 4
+      a = ii( a, b, c, d, in[ 0], S41, 4096336452); # 49
+      d = ii( d, a, b, c, in[ 7], S42, 1126891415); # 50
+      c = ii( c, d, a, b, in[14], S43, 2878612391); # 51
+      b = ii( b, c, d, a, in[ 5], S44, 4237533241); # 52
+      a = ii( a, b, c, d, in[12], S41, 1700485571); # 53
+      d = ii( d, a, b, c, in[ 3], S42, 2399980690); # 54
+      c = ii( c, d, a, b, in[10], S43, 4293915773); # 55
+      b = ii( b, c, d, a, in[ 1], S44, 2240044497); # 56
+      a = ii( a, b, c, d, in[ 8], S41, 1873313359); # 57
+      d = ii( d, a, b, c, in[15], S42, 4264355552); # 58
+      c = ii( c, d, a, b, in[ 6], S43, 2734768916); # 59
+      b = ii( b, c, d, a, in[13], S44, 1309151649); # 60
+      a = ii( a, b, c, d, in[ 4], S41, 4149444226); # 61
+      d = ii( d, a, b, c, in[11], S42, 3174756917); # 62
+      c = ii( c, d, a, b, in[ 2], S43,  718787259); # 63
+      b = ii( b, c, d, a, in[ 9], S44, 3951481745); # 64
+
+      @buf[0] += a
+      @buf[1] += b
+      @buf[2] += c
+      @buf[3] += d
+    end
+
+    def final
+      in :: UInt32[16]
+
+      # save number of bits
+      in[14] = @i[0]
+      in[15] = @i[1]
+
+      # compute number of bytes mod 64
+      mdi = ((@i[0] >> 3) & 0x3F).to_i32
+
+      # pad out to 56 mod 64
+      pad_len = (mdi < 56) ? (56 - mdi) : (120 - mdi)
+      update PADDING.to_unsafe, pad_len
+
+      # append length in bits and transform
+      ii = 0
+      14.times do |i|
+        in[i] = (@in[ii+3].to_u32 << 24) |
+                (@in[ii+2].to_u32 << 16) |
+                (@in[ii+1].to_u32 << 8)  |
+                (@in[ii])
+        ii += 4
+      end
+      transform in
+
+      # store buffer in digest
+      ii = 0
+      4.times do |i|
+        @digest[ii] = (@buf[i] & 0xff).to_u8
+        @digest[ii + 1] = ((@buf[i] >> 8) & 0xFF).to_u8
+        @digest[ii + 2] = ((@buf[i] >> 16) & 0xFF).to_u8
+        @digest[ii + 3] = ((@buf[i] >> 24) & 0xFF).to_u8
+        ii += 4
+      end
+    end
+
+    def hex
+      String.new(32) do |buffer|
+        0.upto(15) do |i|
+          buffer[i * 2] = to_hex((@digest[i]) >> 4)
+          buffer[i * 2 + 1] = to_hex(@digest[i] & 0x0f)
+        end
+        {32, 32}
+      end
+    end
+
+    def to_hex(c)
+      ((c < 10 ? 48_u8 : 87_u8) + c)
+    end
   end
-end
+end