.TH "Digest" 3o source: 2019-01-25 OCamldoc "OCaml library"
.SH NAME
Digest \- MD5 message digest.
.SH Module
Module   Digest
.SH Documentation
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Module
.BI "Digest"
 : 
.B sig  end

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MD5 message digest\&.
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This module provides functions to compute 128\-bit \&'digests\&' of
arbitrary\-length strings or files\&. The digests are of cryptographic
quality: it is very hard, given a digest, to forge a string having
that digest\&. The algorithm used is MD5\&. This module should not be
used for secure and sensitive cryptographic applications\&. For these
kind of applications more recent and stronger cryptographic
primitives should be used instead\&.

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.I type t 
= 
.B string

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The type of digests: 16\-character strings\&.

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.I val compare 
: 
.B t -> t -> int
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The comparison function for 16\-character digest, with the same
specification as 
.B Pervasives\&.compare
and the implementation
shared with 
.B String\&.compare
\&. Along with the type 
.B t
, this
function 
.B compare
allows the module 
.B Digest
to be passed as
argument to the functors 
.B Set\&.Make
and 
.B Map\&.Make
\&.

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.B "Since"
4.00.0

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.I val equal 
: 
.B t -> t -> bool
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The equal function for 16\-character digest\&.

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.B "Since"
4.03.0

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.I val string 
: 
.B string -> t
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Return the digest of the given string\&.

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.I val bytes 
: 
.B bytes -> t
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Return the digest of the given byte sequence\&.

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.B "Since"
4.02.0

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.I val substring 
: 
.B string -> int -> int -> t
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.B Digest\&.substring s ofs len
returns the digest of the substring
of 
.B s
starting at index 
.B ofs
and containing 
.B len
characters\&.

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.I val subbytes 
: 
.B bytes -> int -> int -> t
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.B Digest\&.subbytes s ofs len
returns the digest of the subsequence
of 
.B s
starting at index 
.B ofs
and containing 
.B len
bytes\&.

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.B "Since"
4.02.0

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.I val channel 
: 
.B Pervasives.in_channel -> int -> t
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If 
.B len
is nonnegative, 
.B Digest\&.channel ic len
reads 
.B len
characters from channel 
.B ic
and returns their digest, or raises
.B End_of_file
if end\-of\-file is reached before 
.B len
characters
are read\&.  If 
.B len
is negative, 
.B Digest\&.channel ic len
reads
all characters from 
.B ic
until end\-of\-file is reached and return
their digest\&.

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.I val file 
: 
.B string -> t
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Return the digest of the file whose name is given\&.

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.I val output 
: 
.B Pervasives.out_channel -> t -> unit
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Write a digest on the given output channel\&.

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.I val input 
: 
.B Pervasives.in_channel -> t
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Read a digest from the given input channel\&.

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.I val to_hex 
: 
.B t -> string
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Return the printable hexadecimal representation of the given digest\&.
Raise 
.B Invalid_argument
if the argument is not exactly 16 bytes\&.

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.I val from_hex 
: 
.B string -> t
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Convert a hexadecimal representation back into the corresponding digest\&.
Raise 
.B Invalid_argument
if the argument is not exactly 32 hexadecimal
characters\&.

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.B "Since"
4.00.0

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