how to convert base64 string to byte string?

As there is no native kind of array in elixir, you can’t. But at least there is the Base module, which allows you to decode base64 encoded stuff to a binary.

You can turn it into a list: iex(11)> "Like this 😀" |> Base.encode64 "TGlrZSB0aGlzIPCfmIA=" iex(12)> "TGlrZSB0aGlzIPCfmIA=" |> Base.decode64!() |> :binary.bin_to_list() [76, 105, 107, 101, 32, 116, 104, 105, 115, 32, 240, 159, 152, 128]

Why should one want that? Most of the time, the binary consumes much less memory, and if you are randomly reading bytes from it, its also much faster. Also writing it to a file is probably faster, as it can be read from continous memory, while writing from a list would mean to follow a pointer for e…

The only place I have actually used this is when doing the Cryptopals challenges . I personally found it much easier to follow along when I had lists of bytes.

In fact, I created a aes_key_256 with :base64 format in c# program. To be able to use this key for encryption, I need to convert bytes. I dont know convert it

Well, a binary comes very close to a C-like array. It is a fat pointer with a link to the start of the binary and information about its length. If you need a binary or a list of bytes or something totally different, I can’t tell, as I do not know where you want to use the decoded information. But…

My Code: message = "A very important message." {:ok, aes_256_key} = ExCrypto.generate_aes_key(:aes_256, :base64) {:ok, {init_vec, cipher_text}} = ExCrypto.encrypt(aes_256_key, message) {:ok, val} = ExCrypto.decrypt(aes_256_key, init_vec, cipher_text) Get error blew: (exit) a…

For use in ExCrypto.encrypt/2 you need to generate the key as :bytes.

My Problem is here. I need to have the key to be base64.

Have you tried: {:ok, {init_vec, cipher_text}} = ExCrypto.encrypt(Base.decode64!(aes_256_key), message) ?

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Convert base64 string to byte string

Questions & Help Questions

hoseinisalim July 11, 2018, 2:25pm 15

So I tested it before, but did not answer.