mirror of https://github.com/python/cpython
55 lines
2.1 KiB
TeX
55 lines
2.1 KiB
TeX
\section{\module{hmac} ---
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Keyed-Hashing for Message Authentication}
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\declaremodule{standard}{hmac}
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\modulesynopsis{Keyed-Hashing for Message Authentication (HMAC)
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implementation for Python.}
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\moduleauthor{Gerhard H{\"a}ring}{ghaering@users.sourceforge.net}
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\sectionauthor{Gerhard H{\"a}ring}{ghaering@users.sourceforge.net}
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\versionadded{2.2}
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This module implements the HMAC algorithm as described by \rfc{2104}.
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\begin{funcdesc}{new}{key\optional{, msg\optional{, digestmod}}}
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Return a new hmac object. If \var{msg} is present, the method call
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\code{update(\var{msg})} is made. \var{digestmod} is the digest
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constructor or module for the HMAC object to use. It defaults to
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the \function{\refmodule{hashlib}.md5} constructor. \note{The md5 hash
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has known weaknesses but remains the default for backwards compatibility.
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Choose a better one for your application.}
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\end{funcdesc}
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An HMAC object has the following methods:
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\begin{methoddesc}[hmac]{update}{msg}
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Update the hmac object with the string \var{msg}. Repeated calls
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are equivalent to a single call with the concatenation of all the
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arguments: \code{m.update(a); m.update(b)} is equivalent to
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\code{m.update(a + b)}.
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\end{methoddesc}
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\begin{methoddesc}[hmac]{digest}{}
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Return the digest of the strings passed to the \method{update()}
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method so far. This string will be the same length as the
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\var{digest_size} of the digest given to the constructor. It
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may contain non-\ASCII{} characters, including NUL bytes.
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\end{methoddesc}
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\begin{methoddesc}[hmac]{hexdigest}{}
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Like \method{digest()} except the digest is returned as a string
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twice the length containing
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only hexadecimal digits. This may be used to exchange the value
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safely in email or other non-binary environments.
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\end{methoddesc}
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\begin{methoddesc}[hmac]{copy}{}
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Return a copy (``clone'') of the hmac object. This can be used to
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efficiently compute the digests of strings that share a common
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initial substring.
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\end{methoddesc}
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\begin{seealso}
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\seemodule{hashlib}{The python module providing secure hash functions.}
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\end{seealso}
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