Re: [Acme] RFC 8823 email-reply-00: How to concatenate the tokens?

[Richard Körber <[e-mail]>]

> Rather, you should decode both token-parts, then concatenate the result, and use the result (as a byte array) to do the key-authorization calculation.

RFC 8555 Section 8.1 says:

    A key authorization is a string that
    concatenates the token for the challenge with a key fingerprint,
    separated by a "." character:

    keyAuthorization = token || '.' || base64url(Thumbprint(accountKey))

It further says that "the token for a challenge is a string comprised 
entirely of characters in the URL-safe base64 alphabet. The "||" 
operator indicates concatenation of strings."

So the computation of the key authorization is a purely string-based 
operation. I cannot use the decoded and concatenated byte array for it.

Best,
Richard Körber