I'm trying to hash some strings in a Common Lisp app I'm working on. The sd-sha1 package seems to be unsupported, and has been for some time judging by the CLiki page, which suggests using Ironclad instead. Fair enough,
=> (require 'ironclad)
NIL
Ironclad doesn't do string digests though; this is stated on its project page as an intentional design choice, what I'm supposed to do is convert my string to a byte-string and hash that. In other words
=> (ironclad:digest-sequence
:sha1 (flexi-streams:string-to-octets "Hello there"))
#(114 108 118 85 62 26 63 222 162 145 52 243 110 106 242 234 5 236 92 206)
Ok, now the thing is that the point of this entire excercise is to get out a sha1-hashed string of the original string input, which means that I really want to convert the above back into string format. But,
=> (flexi-streams:octets-to-string
(ironclad:digest-sequence
:sha1 (flexi-streams:string-to-octets "Hello there"))
:external-format :utf-8)
This sequence can't be decoded using UTF-8 as it is too short.
1 octet missing at then end.
[Condition of type FLEXI-STREAMS:EXTERNAL-FORMAT-ENCODING-ERROR]
Restarts:
0: [ABORT] Exit debugger, returning to top level.
The other option is to let flexi-streams
infer the correct encoding.
=> (flexi-streams:octets-to-string
(ironclad:digest-sequence
:sha1 (flexi-streams:string-to-octets "Hello there")))
"rlvU>?Þ¢4ónjòêì\\Î"
Which sort of works, but I get the feeling that the result isn't supposed to contain control characters. According to flexi-streams, the default encoding is :latin
, so I'm really not sure what to do at this stage.
What am I doing wrong? How do I get a string-representation of a SHA1-digested string in Common Lisp?
In case it matters, I'm running SBCL (the version out of apt-get, which is 1.0.29 I believe) through Emacs+SLIME.
The octets you get from ironclad:digest-sequence
are the SHA1 digest. You want a string representing a hexadecimal encoding of those bytes. Ironclad has a function to do that built-in: ironclad:byte-array-to-hex-string
.
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