代碼源自互聯網
調用方法：hex_sha1即可。
/* * *
A JavaScript implementation of the Secure Hash Algorithm, SHA-1, as defined *
in FIPS PUB 180-1 * *
By lizq * *
2006-11-11 * *//* * *
Configurable variables. * */var
hexcase = 0; /*
hex output format. 0 - lowercase; 1 - uppercase */var
chrsz = 8; /*
bits per input character. 8 - ASCII; 16 - Unicode *//* * *
The main function to calculate message digest * */function
hex_sha1(s){ return
binb2hex(core_sha1(AlignSHA1(s))); }/* * *
Perform a simple self-test to see if the VM is working * */function
sha1_vm_test(){ return
hex_sha1("abc")
== "a9993e364706816aba3e25717850c26c9cd0d89d"; }/* * *
Calculate the SHA-1 of an array of big-endian words, and a bit length * */function
core_sha1(blockArray){ var
x = blockArray; //
append padding var
w = Array(80); var
a = 1732584193; var
b = -271733879; var
c = -1732584194; var
d = 271733878; var
e = -1009589776; for
(var
i = 0; i < x.length; i += 16) //
每次處理512位 16*32 { var
olda = a; var
oldb = b; var
oldc = c; var
oldd = d; var
olde = e; for
(var
j = 0; j < 80; j++) //
對每個512位進行80步操作 { if
(j < 16) w[j]
= x[i + j]; else w[j]
= rol(w[j - 3] ^ w[j - 8] ^ w[j - 14] ^ w[j - 16], 1); var
t = safe_add(safe_add(rol(a, 5), sha1_ft(j, b, c, d)), safe_add(safe_add(e, w[j]), sha1_kt(j))); e
= d; d
= c; c
= rol(b, 30); b
= a; a
= t; } a
= safe_add(a, olda); b
= safe_add(b, oldb); c
= safe_add(c, oldc); d
= safe_add(d, oldd); e
= safe_add(e, olde); } return
new
Array(a, b, c, d, e); }/* * *
Perform the appropriate triplet combination function for the current *
iteration * *
返回對應F函數的值 * */function
sha1_ft(t, b, c, d){ if
(t < 20) return
(b & c) | ((~ b) & d); if
(t < 40) return
b ^ c ^ d; if
(t < 60) return
(b & c) | (b & d) | (c & d); return
b ^ c ^ d; //
t<80}/* * *
Determine the appropriate additive constant for the current iteration * *
返回對應的Kt值 * */function
sha1_kt(t){ return
(t < 20) ? 1518500249 : (t < 40) ? 1859775393 : (t < 60) ? -1894007588 : -899497514; }/* * *
Add integers, wrapping at 2^32. This uses 16-bit operations internally * *
to work around bugs in some JS interpreters. * *
將32位數拆成高16位和低16位分別進行相加，從而實現 MOD 2^32 的加法 * */function
safe_add(x, y){ var
lsw = (x & 0xFFFF) + (y & 0xFFFF); var
msw = (x >> 16) + (y >> 16) + (lsw >> 16); return
(msw << 16) | (lsw & 0xFFFF); }/* * *
Bitwise rotate a 32-bit number to the left. * *
32位二進制數循環左移 * */function
rol(num, cnt){ return
(num << cnt) | (num >>> (32 - cnt)); }/* * *
The standard SHA1 needs the input string to fit into a block * *
This function align the input string to meet the requirement * */function
AlignSHA1(str){ var
nblk = ((str.length + 8) >> 6) + 1, blks = new
Array(nblk * 16); for
(var
i = 0; i < nblk * 16; i++) blks[i]
= 0; for
(i = 0; i < str.length; i++) blks[i
>> 2] |= str.charCodeAt(i) << (24 - (i & 3) * 8); blks[i
>> 2] |= 0x80 << (24 - (i & 3) * 8); blks[nblk
* 16 - 1] = str.length * 8; return
blks; }/* * *
Convert an array of big-endian words to a hex string. * */function
binb2hex(binarray){ var
hex_tab = hexcase ? "0123456789ABCDEF"
: "0123456789abcdef"; var
str = ""; for
(var
i = 0; i < binarray.length * 4; i++) { str
+= hex_tab.charAt((binarray[i >> 2] >> ((3 - i % 4) * 8 + 4)) & 0xF) + hex_tab.charAt((binarray[i
>> 2] >> ((3 - i % 4) * 8)) & 0xF); } return
str; }/* * *
calculate MessageDigest accord to source message that inputted * */function
calcDigest(){ var
digestM = hex_sha1(document.SHAForm.SourceMessage.value); document.SHAForm.MessageDigest.value
= digestM; }