That means 128-bit keys are pretty secure if someone was to try every single combination (a brute force attack). To put that into perspective, it’s estimated the whole world has 5,000,000,000,000,000,000,000 grains of sand and with a 128-bit key you’d still have to search every grain of sand on 68,000,000,000,000,000 earth-like planets. Now characters are just represented as numbers on most computers these days so why not just skip straight to numbers? If you had a key which was one bit long (2 1), you’d have 2 combinations as it could just be a 0 or a 1. This increases exponentially with the length of the password.

If you had a 2 character password you’d have 36 x 36 (36 2) which would be 1,296 combinations, and 3 characters would mean 36 x 36 x 36 (36 3) or 46,656 combinations. I’ll show you how to use openssl to encrypt some data and decrypt it using the Common Crypto libraries on iOS.įirst a bit about key size… a key can be considered a password to decrypt the data with except with a password you are limited to characters you can type, to keep it simple lets say this was 26 letters + 10 numbers or 36 characters, if you had a password that was 1 character long you’d have 36 possible combinations to try to un-encrypt your data with.

So you need to keep the key extremely secret however it’s still incredibly useful. If you don’t know what symmetrical encryption is, it means that you use the same key or password to encrypt the data as you do to unencrypt it. AES stands for Advanced Encryption Standard and is an industry-standard algorithm for encrypting data symmetrically which even the US government has approved for SECRET documents.

Download aes 256 bit password generator