Learning Functional Programming in Go

The encrypt and decrypt helper functions

The decrypt helper function in the following code is used by the Decrypt filter. We also have the encrypt helper function, though not in our pipeline, can be nice to have, to encrypt plain text and for testing purposes. 

The decrypt function accepts the encrypted string value. The aes.NewCipher accepts our 32-byte long AES encryption key and returns an AES-256 cipher block, which is passed to NewCBCDecrypter. The NewCBCDecrypter function also accepts an initialization vector (iv), which it uses to decrypt the block in cipher block chaining mode. Its CryptBlocks function is used to decrypt the value, and RightTrim is used to slice off the trailing \x00. Voila! we've got our decrypted string value: