$ curl -O http://pypi.python.org/packages/source/p/pip/pip-1.0.tar.gz
$ tar xvfz pip-1.0.tar.gz
$ cd pip-1.0
$ python setup.py install # may need to be root

#!/usr/bin/env python
#
# sha1 padding/length extension attack class
# by [email protected]
#

import sha
import struct 
import base64

class shaauth:
	def __init__(self, secret, verbose=1):
		self.secret = secret

	def sign(self, msg):
		data = self.secret + msg
		m = sha.new()
		m.update(data)
		sig = m.hexdigest()
		return sig

	def verify(self, msg, sig):
		data = self.secret + msg
		m = sha.new()
		m.update(data)
		sig2 = m.hexdigest()
		return sig2 == sig

# attack class on sha1 length-extension
class shaext:
	def __init__(self, origtext, keylen, origsig):
		self.origtext = origtext 
		self.keylen = keylen
		self.origsig = origsig
		self.addtext = ''
		self.init()

	def init(self):

		count = (self.keylen + len(self.origtext)) * 8
		index = (count >> 3) & 0x3fL
		padLen = 120 - index
        	if index < 56:
            		padLen = 56 - index
	        padding = '\x80' + '\x00' * 63
	        
        	self.input = self.origtext + padding[:padLen] + struct.pack('>Q', count)
        	count = (self.keylen + len(self.input)) * 8
		self.m = sha.new()	
        	self.m.count = [0, count]
        	     
        	_digest = self.origsig.decode("hex")
        	(self.m.H0, self.m.H1, self.m.H2, self.m.H3, self.m.H4) = struct.unpack(">IIIII", _digest)
		
	def add(self, addtext):
		self.addtext = self.addtext + addtext
		self.m.update(addtext)
		
	def final(self):
		new_sig = self.m.hexdigest()
		new_msg = self.input + self.addtext			
		return (new_msg, new_sig)

def testattack():
	key = "topsecret"
	keylen = len(key)
		
	auth = shaauth(key)

	# sign the msg		
	orig_msg = "this is orig test message"
	orig_sig = auth.sign(orig_msg)

	# test the length extension attack		
	add_msg = "this is addition message"
	ext = shaext(orig_msg, keylen, orig_sig)
	ext.add(add_msg)
	(new_msg, new_sig)= ext.final()
		
	# verify the new msg
	assert auth.verify(new_msg, new_sig)

if __name__=="__main__":
	testattack()

function get_age(person_num) 
{
	var month_val = parseInt(document.getElementById('person_dob_month'+person_num).value, 10), 
		day_val = parseInt(document.getElementById('person_dob_day'+person_num).value, 10), 
		yr_val = parseInt(document.getElementById('person_dob_yr'+person_num).value, 10),
		today_date,
		today_year,
		today_month,
		today_day,
		age;
		
	if (day_val > 0 && month_val >= 0 && yr_val > 0) { // only calc if all fields selected
		today_date = new Date();
		today_year = today_date.getFullYear();
		today_month = today_date.getMonth();
		today_day = today_date.getDate();
		age = today_year - yr_val;
		
		if (today_month === month_val) { // birthday is this month
			if (today_day < day_val) { // birthday hasn't happened yet this month, subtract 1 from age
				age--;
			}
		}
		if (age < 0) { // Prevents age from being -1
			age = '';
		}

		document.getElementById('person_age'+person_num).value = age;
	}					
}

<select id="person_dob_month1"  name="person_dob_month1">
<option value="-1"></option>
<option value="0">January</option>
...
<option value="11">December</option>
</select>

<select id="person_dob_day1" name="person_dob_day1">
<option value="0"></option>
<option value="1">1</option>
...
<option value="31">31</option>
</select>

<select id="person_dob_yr1" name="person_dob_yr1">
<option value="0"></option>
<option value="2012">2012</option>
...
<option value="1900">1900</option>
</select>

(day_val > 0 && month_val >= 0 && yr_val > 0)

should be

((day_val > 0) && (month_val >=0) && (yr_val > 0))

function get_age(birth_date){

    var today_date, today_year, age;

    today_date = new Date();

    age =  today_date.getFullYear() - birth_date.getFullYear();
    
    if (day_of_year(today_date) < day_of_year(age_date)){
        age--;
    }
    
    return age;            
    
}

function get_birth_date(person_num){
    //read data from DOM and  return Date object
    return birth_date;
}

function day_of_year(date){
    //figure out day of year and return it
}

//and then call like
var bd = get_birth_date(person_num);
var age = get_age(bd)

if (today_month <  month_val) { // Hasn't had birthday this year
	age--;
}