8 code demo coding by sunrise_chen.
Description, please enter the original code: After the MD5 conversion is:
Overview of 8 Code Coding by Sunrise_Chen.
The full name of Description MD5 is a Message-Digest Algorithm 5 (Information-Summary Algorithm), which is developed by Mit Laboratory for Computer Science and RSA Data Security Inc, which is developed by MD2, MD3, and MD4 in the 1990s. Its role is to make large capacity information to be "compressed" into a confidential format before signing private privacy with digital signature software (that is, transforms an arbitrary length of byte string into a certain length). Whether it is MD2, MD4 or MD5, they all need to obtain a random length of information and generate a 128-bit information summary. Although the structure of these algorithms is more similar, the design of MD2 is completely different from MD4 and MD5, because MD2 is designed for 8-bit machines, while MD4 and MD5 are 32-bit computers. The descriptions of these three algorithms and C language source code have detailed descriptions in Internet RFCS 1321, http://www.ietf.org/rfc/rfc1321.txt), this is the most authoritative document, by Ronald L. Rivest submitted to IEFT in August 1992. Rivest developed an MD2 algorithm in 1989. In this algorithm, the information is first supplied to the information, so that the byte length of the information is a multiple of 16. Then, at a 16-bit test and append to the end of the information. And calculate the hash value based on this new information. Later, Rogier and Chauvaud found that if the test and the MD2 conflict will be generated. The result of the encryption of the MD2 algorithm is unique - neither repeat. In order to enhance the safety of the algorithm, RiveSt has developed an MD4 algorithm in 1990. The MD4 algorithm also needs to fill the information to ensure that the byte length of the information plus 448 can be divided by 512 (information byte length MOD 512 = 448). Then, one of the initial lengths of information indicated by 64-bit binary is added. The information is processed into blocks of 512-bit DAMG? RD / Merkle iterative structure, and each block is to be processed by three different steps. Den Boer and Bosselaers and others quickly discovered the first step and third steps in the MD4 version. Dobbertin demonstrates how to use a regular personal computer to find a conflict in the full version of the MD4 in a few minutes (this conflict is actually a vulnerability, which will result in encryption of different content but may get the same encryption. result). There is no doubt that MD4 is eliminated. Although the MD4 algorithm has such a large vulnerability in the security, it has a guiding role in the presence of several information security encryption algorithms that have been developed thereon. In addition to MD5, there are also SHA-1, RIPE-MD, and HAVAL, etc. One year later, that is, in 1991, Rivest developed technology more approached MD5 algorithm. It adds the concept of "safe-band" (safty-beelts) based on MD4. Although MD5 is slightly slower than MD4, it is safer. This algorithm is obvious by four and MD4 designs with a little different steps. In the MD5 algorithm, the size of the information - summary and the necessary conditions of the filler are identical to the MD4. Den Boer and Bosselaers have discovered pseudo-collisions in the MD5 algorithm, but there is no other resulting result. Van Orschot and Wiener have considered a function of violent search conflicts in hash, and they guess a machine that is designed to search for MD5 conflicts (this machine is approximately manufactured in 1994 It is a million US dollars) to find a conflict every 24 days.
However, from 1991 to 2001, there is no new algorithm for MD6 or other names that have alternative MD5 algorithms, and we can see that this flaw does not have much impact on MD5 security. All of these is not enough to become MD5 problems in practical applications. Also, since the use of the MD5 algorithm does not need to pay any copyright costs, in general (non-top secret applications. But even if the application is in the top secret field, MD5 is not a very good intermediate technology), MD5 It should be considered very safe. 8 code analysis Coding by sunrise_chen.
Source Code
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'--------------------------------------
'Cocoon Disk Manager V3 - MD5 Function
'
'Classic MD5 algorithm ASP implementation
'- taken from a foreign website
'--------------------------------------
PRIVATE CONST BITS_TO_A_BYTE = 8
Private const bytes_to_a_word = 4
PRIVATE const bits_to_a_word = 32
Private m_lonbits (30)
Private M_L2Power (30)
Private function lshift (Lvalue, iShiftBits)
IF iShiftBits = 0 THEN
Lshift = LVALUE
EXIT FUNCTION
Elseif ishiftBits = 31 THEN
IF Lvalue and 1 THEN
Lshift = & h80000000
Else
Lshift = 0
END IF
EXIT FUNCTION
Elseif IshiftBits <0 or iShiftBits> 31 THEN
Err.raise 6
END IF
IF (LValue and M_L2Power (31 - IshiftBits)) THEN
Lshift = ((Lvalue and M_lonbits (31 - (iShiftBits 1))) * m_l2power (iShiftBits)) or & h80000000
Else
Lshift = ((Lvalue and M_Lonbits) * m_l2power (iShiftBits))
END IF
END FUNCTION
Private function Rshift (Lvalue, IshiftBits)
IF iShiftBits = 0 THEN
Rshift = LVALUE
EXIT FUNCTION
Elseif ishiftBits = 31 THEN
If Lvalue and & H80000000 THEN
Rshift = 1
Else
Rshift = 0
END IF
EXIT FUNCTION
Elseif IshiftBits <0 or iShiftBits> 31 THEN
Err.raise 6
END IF
Rshift = (LValue and & H7ffffe) / M_L2Power (iShiftBits)
IF (Lvalue and & H80000000) THEN
Rshift = (RSHIFT OR (& H400000 / M_L2Power (IshiftBits - 1)))
END IF
End FunctionPrivate Function RotateLeft (Lvalue, iShiftBits)
Rotateleft = Lshift (Lvalue, IshiftBits) or Rshift (Lvalue, (32 - IshiftBits))
END FUNCTION
Private function addunsigned (lx, ly)
DIM LX4
DIM LY4
DIM LX8
DIM LY8
DIM LRESULT
Lx8 = lx and & h80000000
LY8 = ly and & h80000000
LX4 = lx and & h40000000
LY4 = Ly and & H40000000
LRESULT = (lx and & h3ffffff) (Ly and & H3FFFFFF)
IF lx4 and ly4 Then
Lresult = LRESULT XOR & H80000000 XOR LX8 XOR LY8
Elseif Lx4 or Ly4 Then
If LRESULT AND & H40000000 THEN
LResult = LRESULT XOR & HC0000000 XOR LX8 XOR LY8
Else
Lresult = LRESULT XOR & H40000000 xor LX8 XOR LY8
END IF
Else
LResult = LRESULT XOR LX8 XOR LY8
END IF
Addunsigned = LRESULT
END FUNCTION
Private function MD5_f (x, y, z)
MD5_F = (x and y) OR ((not x) and z)
END FUNCTION
Private function MD5_G (x, y, z)
MD5_G = (x and z) OR (Y AND (NOT Z))
END FUNCTION
Private function MD5_H (x, y, z)
MD5_H = (x xor y xor z)
END FUNCTION
Private function MD5_i (x, y, z)
MD5_i = (y xor (x or (not z))))
END FUNCTION
Private SUB MD5_FF (A, B, C, D, X, S, AC)
A = AddunSigned (A, AddunSigned (addunsigned (MD5_F (B, C, D), X), AC)
a = rotateleft (a, s)
A = addunsigned (a, b)
End Sub
Private SUB MD5_GG (A, B, C, D, X, S, AC)
A = addunsigned (A, AddunSigned (addunsigned (MD5_G (B, C, D), X), AC)
a = rotateleft (a, s)
A = addunsigned (a, b)
End Sub
Private SUB MD5_HH (A, B, C, D, X, S, AC)
A = addunsigned (A, AddunSigned (addunsigned (MD5_H (B, C, D), X), AC)
a = rotateleft (a, s)
A = addunsigned (a, b)
End Sub
Private SUB MD5_II (A, B, C, D, X, S, AC)
A = addunsigned (A, AddunSigned (AddunSigned (MD5_i (B, D), X), AC)) A = RotateLeft (A, S)
A = addunsigned (a, b)
End Sub
Private function convertToWordArray (SMESSAGE)
Dim LMessageLength
Dim lnumberofwords
Dim lwordArray ()
DIM LBYTEPSITION
DIM LBYTECOUNT
Dim lwordcount
Const modulus_bits = 512
Const congruent_bits = 448
LMessageLength = Len (SMESSAGE)
Lnumberofwords = ((LMessageLength ((MODULUS_BITS - CONGRUENT_BITS / BITS_TO_A_BYTE)) / (MODULUS_BITS / BITS_TO_A_BYTE)) 1) * (MODULUS_BITS / BITS_TO_A_WORD)
Redim LWordArray (LnumberofWords - 1)
lbyteposition = 0
lbytecount = 0
DO Until Lbytecount> = LMESSAGELENGTH
LWORDCOUNT = lbytecount / bytes_to_a_word
LbytePosition = (lbytecount mod bytes_to_a_word) * bits_to_a_byte
LWordArray (LWORDCOUNT) OR LSHIFT (ASC (MID (SMESSAGE, LBYTECUNT 1, 1)), LBYTEPOSITION
lbytecount = lbytecount 1
Loop
LWORDCOUNT = lbytecount / bytes_to_a_word
LbytePosition = (lbytecount mod bytes_to_a_word) * bits_to_a_byte
LWordArray (lwordcount) = lwordArray (lwordcount) or lshift (& H80, lbyteposition)
LWordArray (lnumberofwords - 2) = lshift (LMessageLength, 3)
LWordArray (Lnumberofwords - 1) = RSHIFT (LMessageLength, 29)
ConvertToWordArray = LWORDARRAY
END FUNCTION
Private function Wordtohex (LValue)
DIM LBYTE
DIM LCOUNT
For LCOUNT = 0 TO 3
Lbyte = RSHIFT (LVALUE, LCOUNT * BITS_TO_A_BYTE) AND M_LONBITS (Bits_TO_A_BYTE - 1)
Wordtohex = WordToHex & Right ("0" & HEX (LbyTe), 2)
NEXT
END FUNCTION
Public Function MD5 (SMESSAGE)
m_lonbits (0) = ClNG (1)
M_lonbits (1) = CLNG (3)
M_lonbits (2) = CLNG (7)
M_lonbits (3) = CLNG (15) M_LONBITS (4) = CLNG (31)
M_lonbits (5) = clng (63)
M_lonbit (6) = CLNG (127)
M_lonbits (7) = CLNG (255)
M_lonbits (8) = CLNG (511)
m_lonbits (9) = CLNG (1023)
M_lonbits (10) = CLNG (2047)
M_lonbits (11) = clng (4095)
M_lonbits (12) = CLNG (8191)
m_lonbits (13) = CLNG (16383)
M_lonbits (14) = CLNG (32767)
M_lonbits (15) = CLNG (65535)
M_lonbits (16) = CLNG (131071)
M_lonbits (17) = CLNG (262143)
M_lonbits (18) = CLNG (524287)
M_lonbits (19) = clng (1048575)
M_lonbits (20) = CLNG (2097151)
M_lonbits (21) = clng (4194303)
M_lonbits (22) = CLNG (8388607)
M_lonbits (23) = CLNG (16777215)
M_LONBITS (24) = CLNG (33554431)
M_LONBITS (25) = CLNG (67108863)
M_lonbits (26) = CLNG (134217727)
M_lonbit (27) = CLNG (268435455)
M_lonbit (28) = CLNG (536870911)
M_lonbits (29) = CLNG (1073741823)
M_lonbits (30) = clng (2147483647)
m_l2power (0) = CLNG (1)
M_L2Power (1) = CLNG (2)
M_L2Power (2) = CLNG (4)
M_L2Power (3) = CLNG (8)
M_L2Power (4) = CLNG (16)
M_L2Power (5) = CLNG (32)
M_L2Power (6) = CLNG (64)
M_L2Power (7) = clng (128)
M_L2Power (8) = CLNG (256)
M_L2Power (9) = CLNG (512)
M_L2Power (10) = CLNG (1024)
M_L2Power (11) = CLNG (2048)
M_L2Power (12) = CLNG (4096)
M_L2Power (13) = clng (8192)
M_L2Power (14) = CLNG (16384)
M_L2Power (15) = CLNG (32768)
M_L2Power (16) = CLNG (65536)
m_l2power (17) = CLNG (131072)
M_L2Power (18) = CLNG (262144)
M_L2Power (19) = CLNG (524288)
M_L2Power (20) = clng (1048576)
M_L2Power (21) = CLNG (2097152)
M_L2Power (22) = CLNG (4194304)
M_L2Power (23) = CLNG (8388608)
M_L2Power (24) = CLNG (16777216)
M_L2Power (25) = CLNG (33554432) M_L2Power (26) = CLNG (67108864)
M_L2Power (27) = CLNG (134217728)
M_L2Power (28) = CLNG (268435456)
M_L2Power (29) = CLNG (536870912)
M_L2Power (30) = CLNG (1073741824)
DIM X
DIM K
DIM AA
DIM BB
DIM CC
DIM DD
DIM A
DIM B
DIM C
DIM D
Const S11 = 7
Const S12 = 12
Const S13 = 17
Const S14 = 22
Const S21 = 5
Const S22 = 9
Const S23 = 14
Const S24 = 20
Const S31 = 4
Const S32 = 11
Const S33 = 16
Const S34 = 23
Const S41 = 6
Const S42 = 10
Const S43 = 15
Const S44 = 21
x = ConvertToWordArray (SMESSAGE)
A = & h67452301
B = & hefcdab89
C = & H98BADCFE
D = & h10325476
For K = 0 to Ubound (x) STEP 16
AA = a
BB = B
CC = C
DD = D
MD5_FF A, B, C, D, X (K 0), S11, & HD76AA478
MD5_FF D, A, B, C, X (K 1), S12, & HE8C7B756
MD5_FF C, D, A, B, X (K 2), S13, & H242070DB
MD5_FF B, C, D, A, X (k 3), S14, & HC1BDCEEE
MD5_FF A, B, C, D, X (K 4), S11, & HF57C0FAF
MD5_FF D, A, B, C, X (K 5), S12, & H4787C62A
MD5_FF C, D, A, B, X (K 6), S13, & Ha8304613
MD5_FF B, C, D, A, X (K 7), S14, & HFD469501
MD5_FF A, B, C, D, X (K 8), S11, & H698098D8
MD5_FF D, A, B, C, X (K 9), S12, & H8B44F7AF
MD5_FF C, D, A, B, X (K 10), S13, & HFFFF5BB1
MD5_FF B, C, D, A, X (K 11), S14, & H895CD7BE
MD5_FF A, B, C, D, X (k 12), S11, & H6B901122
MD5_FF D, A, B, C, X (K 13), S12, & HFD987193
MD5_FF C, D, A, B, X (K 14), S13, & Ha679438E
MD5_FF B, C, D, A, X (K 15), S14, & H49B40821
MD5_GG A, B, C, D, X (K 1), S21, & HF61E2562
MD5_GG D, A, B, C, X (K 6), S22, & HC040B340
MD5_GG C, D, A, B, X (K 11), S23, & H265E5A51
MD5_GG B, C, D, A, X (k 0), S24, & HE9B6C7AA
MD5_GG A, B, C, D, X (K 5), S21, & HD62F105D
MD5_GG D, A, B, C, X (K 10), S22, & H2441453
MD5_GG C, D, A, B, X (K 15), S23, & HD8A1E681
MD5_GG B, C, D, A, X (K 4), S24, & HE7D3FBC8
MD5_GG A, B, C, D, X (K 9), S21, & H21E1CDE6
MD5_GG D, A, B, C, X (k 14), S22, & HC33707D6
MD5_GG C, D, A, B, X (K 3), S23, & HF4D50D87
MD5_GG B, C, D, A, X (K 8), S24, & H455A14ED
MD5_GG A, B, C, D, X (K 13), S21, & HA9E3E905
MD5_GG D, A, B, C, X (K 2), S22, & HFCEFA3F8
MD5_GG C, D, A, B, X (K 7), S23, & H676F02D9
MD5_GG B, C, D, A, X (K 12), S24, & H8D2A4C8A
MD5_HH A, B, C, D, X (K 5), S31, & HFFFA3942
MD5_HH D, A, B, C, X (K 8), S32, & H8771F681
MD5_HH C, D, A, B, X (K 11), S33, & H6D9D6122
MD5_HHH B, C, D, A, X (k 14), S34, & HFDE5380C
MD5_HH A, B, C, D, X (k 1), S31, & Ha4bee44
MD5_HH D, A, B, C, X (K 4), S32, & H4BDECFA9
MD5_HH C, D, A, B, X (K 7), S33, & HF6BB4B60
MD5_HHH B, C, D, A, X (K 10), S34, & HBebfbc70
MD5_HH A, B, C, D, X (K 13), S31, & H289B7EC6
MD5_HH D, A, B, C, X (K 0), S32, & HeaA127FA
MD5_HH C, D, A, B, X (K 3), S33, & HD4EF3085
MD5_HHH B, C, D, A, X (K 6), S34, & H4881D05
MD5_HH A, B, C, D, X (K 9), S31, & HD9D4D039
MD5_HH D, A, B, C, X (K 12), S32, & HE6DB99E5
MD5_HH C, D, A, B, X (K 15), S33, & H1FA27CF8
MD5_HHH B, C, D, A, X (K 2), S34, & HC4AC5665
MD5_II A, B, C, D, X (K 0), S41, & HF4292244
MD5_II D, A, B, C, X (K 7), S42, & H432AFF97MD5_II C, D, A, B, X (K 14), S43, & HAB9423A7
MD5_II B, C, D, A, X (k 5), S44, & HFC93A039
MD5_II A, B, C, D, X (k 12), S41, & H655B59C3
MD5_II D, A, B, C, X (K 3), S42, & H8F0CCC92
MD5_II C, D, A, B, X (K 10), S43, & HFFEFF47D
MD5_II B, C, D, A, X (k 1), S44, & H85845DD1
MD5_II A, B, C, D, X (K 8), S41, & H6FA87E4F
MD5_II D, A, B, C, X (K 15), S42, & HFE2CE6E0
MD5_II C, D, A, B, X (K 6), S43, & HA3014314
MD5_II B, C, D, A, X (K 13), S44, & H4E0811A1
MD5_II A, B, C, D, X (K 4), S41, & HF7537E82
MD5_II D, A, B, C, X (K 11), S42, & HBD3AF235
MD5_II C, D, A, B, X (K 2), S43, & H2AD7D2BB
MD5_II B, C, D, A, X (K 9), S44, & HEB86D391
A = addunsigned (A, AA)
B = addunsigned (b, bb)
C = addunsigned (C, CC)
D = addunsigned (D, DD)
NEXT
MD5 = LCase (WordTohex (a) & WordTohex (B) & WordTohex (C) & WordToHex (D))
END FUNCTION
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