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util.digest
- Message digester frameworkThis module provides a base class and common interface for
message digest algorithms, such as MD5 (see rfc.md5
- MD5 message digest)
and SHA (see rfc.sha
- SHA message digest).
A typical way to compute a message digest would be as follows:
(use rfc.sha) ; import actual digest implementation (use util.digest) (digest-message-to 'base64url <sha256> "message")
You can use different algorithms, and choose different output
format (e.g. u8vector, hexadecimal string, etc.)
If you need to digest with a secret key, see rfc.hmac
- HMAC keyed-hashing.
To digest a message, you can use the following API.
{util.digest} Compute a digest of message using algorithm implemented by digester, and returns as an instance of class target.
The message argument may be a string or a u8vector.
The digester argument must be a class inheriting
<message-digest-algorithm>
and implementing the digester protocol
described below. Gauche provides SHA
(see rfc.sha
- SHA message digest) and MD5 (see rfc.md5
- MD5 message digest) by
default.
The supported target class is <u8vector>
and <string>
.
Digest result is a bytestring in general, so using <u8vector>
is recommended; if you give <string>
, the result
is likely to be an incomplete string.
For the convnience, the following symbols are also allowed as target,
in which case the output byte sequence is encoded to a readable string
For the details of those encodings, see rfc.base64
- Base64 encoding/decoding.
base64
Base64 encoding (original).
base64url
URL-safe Base64 encoding.
base64url-nopad
URL-safe Base64 encoding and omitting trailing padding character (=
)
base32
Base32 encoding.
base32hex
Base32hex encoding.
base16
Base16 encoding, a.k.a. hexadecimal encoding (using #[0-9A-F]
.
hex
Base16 encoding but use lowercase letters (using #[0-9a-f]
.
Read input from the current input port until EOF, compute
its digest using the algorithm specified by digester,
and returns result in an instance of a class given to target.
You can also give some symbols to specify encodings as target.
See digest-message-to
above for the details of
target and digester.
{util.digest}
The following API is for the impelmenter of the actual digest aglrithms.
{util.digest} A metaclass of message digest algorithm implementation.
Specifies the block size (in bytes), which is specific to each algorithm. (This is a slot for each class object that implements the algorithm, not for instance of such classes. Only the author of such digest classes needs to care. See ext/digest/sha.scm in the source tree for more details.)
{util.digest} A base class of message digest algorithm implementation.
The concrete subclass of message digest algorithm has to implement the following methods.
{util.digest} Takes the instance of massage-digest algorithm, and updates it with the data data, which can be either a u8vector or a (possibly incomplete) string.
{util.digest} Finalizes the instance of message-digest algorithm, and returns the digest result in an incomplete string.
{util.digest} A wrapper of digest routines. Given message-digest algorithm class, this function reads the input data from current input port until EOF, and returns the digest result in an incomplete string.
{util.digest}
Deprecated.
Use digest-message-to
for the new code.
Same as (digest-message-to <string> class string)
,
where only a string is allowed to the string argument.
{util.digest}
Deprecated.
Same as (base16-encode-message digest-result :lowercase #t)
(see rfc.base64
- Base64 encoding/decoding). In typical case, you can pass
hex
as the target to digest-message-to
to get
the hexified output directly. This procedure is only kept for
the backward compatibility.
Next: util.dominator
- Calculate dominator tree, Previous: util.combinations
- Combination library, Up: Library modules - Utilities [Contents][Index]