Encoded key not equal to its input. about fernet-go

[kr]

BecstsYSkJY33Us91kgl6qPubHowWXcqaBxqhu7Nu6_= is invalid base64 data.
DecodeKey should be returning an error, but it's not. I'll fix this.

[kr]

Wait, that's not it. The string is valid URL-safe-flavor base64. Still investigating.

[kr]

Data to be encoded in base64 is padded with 0 to a multiple of 6 bits.
Each group of 6 bits is then encoded into an ascii char, and the whole
string is then padded with = to a multiple of 4 chars.

When decoding, the process is reversed, and padding is discarded
in the process. The go base64 package checks the = padding for
validity, but apparently it silently discards the binary 0 padding.
If any of this padding is nonzero, it is silently ignored.

The base64 rfc doesn't say what to do with invalid 0 padding.
I'll test some other implementations (python, ruby, and the reference
implementation at http://josefsson.org/base-encoding/, for starters)
to see how they handle this.

It's possible that some base-64 encodings are simply not unique.