Anyone got a SHA-256 function for PHP4?

[chigley]

Hi guys,

 

Been trying to make sense of the SHA-256 algorithm for days now, but the specification just doesn't make any sense. I've found a few classes when Googling about but ideally I just need a standalone function. I found this pseudocode on the Wikipedia article but I can't make much sense of it really!

 

Note: All variables are unsigned 32 bits and wrap modulo 232 when calculating

Initialize variables
(first 32 bits of the fractional parts of the square roots of the first 8 primes 2..19):
h0 := 0x6a09e667
h1 := 0xbb67ae85
h2 := 0x3c6ef372
h3 := 0xa54ff53a
h4 := 0x510e527f
h5 := 0x9b05688c
h6 := 0x1f83d9ab
h7 := 0x5be0cd19

Initialize table of round constants
(first 32 bits of the fractional parts of the cube roots of the first 64 primes 2..311):
k[0..63] :=
  0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
  0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
  0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
  0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
  0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
  0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
  0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
  0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2

Pre-processing:
append the bit '1' to the message
append k bits '0', where k is the minimum number >= 0 such that the resulting message
   length (in bits) is congruent to 448 (mod 512)
append length of message (before pre-processing), in bits, as 64-bit big-endian integer

Process the message in successive 512-bit chunks:
break message into 512-bit chunks
for each chunk
   break chunk into sixteen 32-bit big-endian words w[0..15]

   Extend the sixteen 32-bit words into sixty-four 32-bit words:
   for i from 16 to 63
       s0 := (w[i-15] rightrotate 7) xor (w[i-15] rightrotate 18) xor (w[i-15] rightshift 3)
       s1 := (w[i-2] rightrotate 17) xor (w[i-2] rightrotate 19) xor (w[i-2] rightshift 10)
       w[i] := w[i-16] + s0 + w[i-7] + s1

   Initialize hash value for this chunk:
   a := h0
   b := h1
   c := h2
   d := h3
   e := h4
   f := h5
   g := h6
   h := h7

   Main loop:
   for i from 0 to 63
       s0 := (a rightrotate 2) xor (a rightrotate 13) xor (a rightrotate 22)
       maj := (a and b) xor (a and c) xor (b and c)
       t2 := s0 + maj
       s1 := (e rightrotate 6) xor (e rightrotate 11) xor (e rightrotate 25)
       ch := (e and f) xor ((not e) and g)
       t1 := h + s1 + ch + k[i] + w[i]

       h := g
       g := f
       f := e
       e := d + t1
       d := c
       c := b
       b := a
       a := t1 + t2

   Add this chunk's hash to result so far:
   h0 := h0 + a
   h1 := h1 + b 
   h2 := h2 + c
   h3 := h3 + d
   h4 := h4 + e
   h5 := h5 + f
   h6 := h6 + g 
   h7 := h7 + h

Produce the final hash value (big-endian):
digest = hash = h0 append h1 append h2 append h3 append h4 append h5 append h6 append h7

 

If any of you can help I'd really appreciate it

 

Chigley

[neel_basu]

Look at the phpinfo(); I am sure that SHA-256 Algo is already Installed.

You dont need to create by yourself.

[chigley]

I need a custom function for use on many servers, some of which will not have the PHP default functions availiable.

[neel_basu]

almost 99.99% servers allows all these algo(s).

else get a free host and make a php script there that do's this Hashing job and output's the SHA-256 hashed string. and use that url in all of your applications.

[chigley]

That's out of the question I need a function that will work on any server without calling any of my sites, some of them will have the default functions disabled so I really need a standalone. I just don't understand this bit of the Wiki:

 

Pre-processing:
append the bit '1' to the message
append k bits '0', where k is the minimum number >= 0 such that the resulting message
    length (in bits) is congruent to 448 (mod 512)
append length of message (before pre-processing), in bits, as 64-bit big-endian integer

 

Nor do I understand most of it to be honest...

 

Thanks

[neel_basu]

See the source of PHP SHA-256 Algorithm.

[chigley]

Where can I find this? The PHP source isn't very easy to navigate... I've tried looking for function sources before but don't know where to find them in the PHP source.

 

Thanks a lot for your help

[neel_basu]

If you cant use SHA algo through PHP YOu still can do it using MySQL

Use this query bellow.

select sha1('TheOriginalText');

[seb hughes]

You need a new host if they don't let you use sha1 in php, why can't you use MD5?

[chigley]

It's not my host. My clients' hosts do not have the hash() type functions available, and I need to get a custom function done as soon as possible. MD5 is out of the question I'm afraid

[neel_basu]

If you cant use SHA algo through PHP YOu still can do it using MySQL

Use this query bellow.

select sha1('TheOriginalText');

Did you looked at this Reply ??

[chigley]

I need SHA-256, which requires an addon for mySQL. Also, some of the uses are not for databases.

[neel_basu]

I've never faced Such a problem.