That is, any number in the shown ranges is valid, although in bit terms that only happens in 8-bit increments. Even though CAST5 supports key lengths lower than bits 16 bytes , in fact they will just be zero-padded to the maximum length, as specified in RFC Blowfish supports key lengths as small as 32 bits 4 bytes , but our tests have shown that only lengths of bits 16 bytes or higher are properly supported by both MCrypt and OpenSSL.
It is also a bad practice to use such low-length keys anyway. This is because drivers support different modes for these ciphers. Also, it is important to note that AES and Rijndael are actually the same cipher, but only when used with a bit key.
However, both drivers implement them differently and they are not portable. It is probably worth noting that we only found one obscure source confirming that it is MCrypt that is not properly implementing it. Different modes of encryption have different characteristics and serve for different purposes. Some are stronger than others, some are faster and some offer extra features. The table below is to provide brief informational reference to our more experienced users.
If you are a beginner, just stick to the CBC mode - it is widely accepted as strong and secure for general purposes. This is influenced by the cipher algorithm itself, the IV prepended to the cipher-text and the HMAC authentication message that is also prepended. Furthermore, the encrypted message is also Baseencoded so that it is safe for storage and transmission, regardless of a possible character set in use.
Keep this information in mind when selecting your data storage mechanism. Cookies, for example, can only hold 4K of information. For usability, performance, but also historical reasons tied to our old Encrypt Class , the Encryption library is designed to use repeatedly the same driver, encryption cipher, mode and key. If you wish to change that however, you need to use the initialize method. It accepts an associative array of parameters, all of which are optional:. For example, if you were to change the encryption algorithm and mode to AES in CTR mode, this is what you should do:.
Note that we only mentioned that you want to change the ciper and mode, but we also included a key in the example. As previously noted, it is important that you choose a key with a proper size for the used algorithm. Encrypting and decrypting data with the already configured library settings is simple. Here is an example of a password that I need to be decrypted:.
I think I can handle the re-encryption, I just have no idea how to decrypt these things. Thank you to anyone that can help! Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Codeigniter Password Decryption Ask Question.
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