Why is encryption algorithm may give different results in AS3 and PHP?
In AS3 I use library from http://labs.boulevart.be/index.php/2007/05/23/encryption-in-as2-and-as3/.
And in PHP I use RC4 Cipher.
Could some tell me what is the problem? Thanks.
How are you comparing the two results? You could be looking at one result display as a hex string, and another in ASCII for example. Have you also tried comparing the result to online (such as from Wikipedia) test vector for some simple strings to see if you are getting expected result?
Assuming the obvious like having the same key and initialisation values, you may want to look at the endianness assumptions of the two implementations.
If initial vector (iv) of the encryption libraries in not same (and it is unlikely to be the same as it should be random) the encryption will not give you same result.
If you want to check - check encryption with one and decryption with other and vise-verse
Related
What is the best way to create a short (6 chars), random, and with low collison probability? I need to create short links like bit.ly.
The problem of md5, sha1, uniqid etc. is that they don't generate uppercase characters, so I'm looking for a case-sensitive output to have a wider range of possible values...
I like to use Hashids for this kind of thing:
Hashids is a small open-source library that generates short, unique, non-sequential ids from numbers.
It converts numbers like 347 into strings like “yr8”, or array of numbers like [27, 986] into “3kTMd”.
You can also decode those ids back. This is useful in bundling several parameters into one or simply using them as short UIDs.
Hashids has been ported to many languages, including PHP.
(Note that, despite the name, Hashids is not a true hashing system since it is designed to be reversible.)
I've been playing around with php mcrypt over the weekend with AES used to encrypt text strings with a key. Later I worked up a tiny php tool to encrypt / decrypt your strings with AES/mcrypt now when the key is "wrong" and the text doesn't get decrypted, you end up with what I think is binary from what I've read around (http://i.imgur.com/jF8cZMZ.png), is there anyway in PHP to check if the variable holds binary or a properly decoded string?
My apologies if the title and the intro are a bit misleading.
When you encrypt text and then try to decrypt it, you will get the same text, but when you try to decrypt random data, there is a small chance that the result will be text (decreasing with length of data). You haven't specified what kind of data we are talking about, but determining if the decryption is successful by applying a heuristic is a bad idea. It is slow and may lead to false positives.
You should have a checksum or something like that to determine if the decrypted result is valid. This could be easily done by running sha1 on the plaintext data, prepend the result to the text and encrypt it as a whole. When you decrypt it, you can split (sha1 output has a fixed size, so you know where to split) the resulting string run sha1 on the text part and compare with the hash part. If it matches you have a valid result. You can of course improve the security a little by using SHA-256 or SHA-512.
That's is just one way of doing it, but might not be the best. Better ways would be to use an authenticated mode of operation for AES like GCM or CCM, or use encrypt-then-MAC with a good MAC function like HMAC-SHA512.
With using the approaches above you're free to use any kind of data to encrypt, because you're not limited to determining if it is text or not anymore.
When I apply Crypt::encrypt(1) I'm getting this encrypted string:
eyJpdiI6IlBoQnliQkZkb0NPT1g5NG9FbkpqV2hLa3ZLUnlWSEFRMEZwM2YxTEdNVk09IiwidmFsdWUiOiJ0N0kyWmZvRWVETzE3WTJWVU5DS1ZpTVFYTGpXNHQxT2YyQWdsMFgxK0xvPSIsIm1hYyI6IjAzMjAzNzdhNzZmYmZiZDVkZGJkMjM5MWY5NjhkNzJjMWFhMzNiYmYyZDJkODNlMmFkODcyNzdhYTE3ZjFkODMifQ==
Is it possible to make string shorter (4-5 times shorter) in Laravel, using the same two-way encryption?
What you want to do, instead of encrypting uri portion is obfuscate it. For example, one of the great libraries for php is Hashids
I have the luxury of starting from scratch, so I'm wondering what would be a good hash to use between PHP and Python.
I just need to be able to generate the same hash from the same text in each language.
From what I read, PHP's md5() isn't going to work nicely.
md5() always plays nicely - it always does the same thing because it is a standard hashing format.
The only tripping hazard is that some languages default return format for an MD5 hash is a 32 byte ascii string containing hexadecimal characters, and some use a 16 byte string containing a literal binary representation of the hash.
PHP's md5() by default returns a 32-byte string, but if you pass true to the second argument, it will return the 16 byte form instead. So as long as you know which version your other language uses (in you case Python), you just need to make sure that you get the correct format from PHP.
You may be better using the 32-byte form anyway, depending on how your applications communicate. If you use a communication protocol based on plain-text (such as HTTP) it is usually safer to use plain-text versions of anything - binary, in this case, is smaller, but liable to get corrupted in transmission by badly written servers/clients.
The binary vs. ascii problem applys to just about any hashing algorithm you can think of.
What is it you want from the hash? (portability, security, performance....)
From what I read, PHP's md5() isn't going to work nicely.
What did you read? Why won't it work?
I just need to be able to generate the same hash from the same text in each language
Since PHP only provides crc32 (very insecure), md5 and sha1 out of the box, it's not exactly a huge amount of testing you need to do. Of course if portability is not an issue then there's the mcrypt and openssl apis available. And more recently the hash PECL gives you a huge choice.
I suggest to use sha1 as it is implemented out of the box in both but has no collision valnurabilities like md5. See: http://en.wikipedia.org/wiki/MD5#Collision_vulnerabilities
I'd like to have a super simple / fast encrypt/decrypt function for non-critical pieces of data. I'd prefer the encryped string to be url-friendly (bonus points for pure alphanumerics), and no longer than it has to be. Ideally it should have some sort of key or other mechanism to randomize the cipher as well.
Because of server constraints the solution should not use mcrypt. Ideally it should also avoid base64 because of easier decrypting.
Example strings:
sample#email_address.com
shortstring
two words
or three words
555-123-4567
Capitals Possible?
You will probably have to code it yourself, but a Vigenère cypher on the characters A-Z, a-z, 0-9 should meet your needs.
With careful key generation and a long key (ideally longer than the encrypted text) Vigenère can be secure, but you have to use it very carefully to ensure that.
There's a wide variety of easy-to-implement ciphers around, such as XTEA. Don't invent your own, or use a trivially broken one like the vigenere cipher. Better yet, don't do this at all - inventing your own cryptosystems is fraught with danger, and if you don't want your users to view the data, you probably shouldn't be sending it to them in the first place.