PasswordConfirmation.php

<?php

class App_Validate_PasswordConfirmation extends Zend_Validate_Abstract {

	const NOT_MATCH = 'notMatch';
	
	protected $_messageTemplates = array(
		self::NOT_MATCH => 'Password confirmation does not match'
	);
	
	public function isValid($value, $context = null) {
		$value = (string) $value;
		$this->_setValue($value);
		
		if (is_array($context)) {
			if (
				isset($context['password_confirm']) && 
				($value == $context['password_confirm'])) {
					return true;
			}
		} elseif (is_string($context) && ($value == $context)) {
			return true;
		}
		
		$this->_error(self::NOT_MATCH);
		return false;
	}
}