Question

I am attempting to decrypt a number encrypted by another program that uses the BouncyCastle library for Java.

In Java, I can set the key like this: key = Hex.decode("5F3B603AFCE22359");

I am trying to figure out how to represent that same step in Ruby.

Answer 1

To get Integer — just str.hex. You may get byte array in several ways:

str.scan(/../).map(&:hex)
[str].pack('H*').unpack('C*')
[str].pack('H*').bytes.to_a

See other options for pack/unpack and examples (by codeweblog).