Digest::SHA3 - phpMan

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NAME
    Digest::SHA3 - Perl extension for SHA-3

SYNOPSIS
    In programs:

                    # Functional interface

            use Digest::SHA3 qw(sha3_224 sha3_256_hex sha3_512_base64 ...);

            $digest = sha3_224($data);
            $digest = sha3_256_hex($data);
            $digest = sha3_384_base64($data);
            $digest = sha3_512($data);

                    # Object-oriented

            use Digest::SHA3;

            $sha3 = Digest::SHA3->new($alg);

            $sha3->add($data);              # feed data into stream

            $sha3->addfile(*F);
            $sha3->addfile($filename);

            $sha3->add_bits($bits);
            $sha3->add_bits($data, $nbits);

            $digest = $sha3->digest;        # compute digest
            $digest = $sha3->hexdigest;
            $digest = $sha3->b64digest;

                    # Compute extendable-length digest

            $sha3 = Digest::SHA3->new(128000)->add($data);  # SHAKE128
            $digest  = $sha3->squeeze;
            $digest .= $sha3->squeeze;
            ...

            $sha3 = Digest::SHA3->new(256000)->add($data);  # SHAKE256
            $digest  = $sha3->squeeze;
            $digest .= $sha3->squeeze;
            ...

ABSTRACT
    Digest::SHA3 is a complete implementation of the NIST SHA-3
    cryptographic hash function, as specified in FIPS 202 (SHA-3 Standard:
    Permutation-Based Hash and Extendable-Output Functions).

    The module gives Perl programmers a convenient way to calculate
    SHA3-224, SHA3-256, SHA3-384, and SHA3-512 message digests, as well as
    variable-length hashes using SHAKE128 and SHAKE256. Digest::SHA3 can
    handle all types of input, including partial-byte data.

DESCRIPTION
    Digest::SHA3 is written in C for speed. If your platform lacks a C
    compiler, perhaps you can find the module in a binary form compatible
    with your particular processor and operating system.

    The programming interface is easy to use: it's the same one found in
    CPAN's Digest module. So, if your applications currently use Digest::SHA
    and you'd prefer the newer flavor of the NIST standard, it's a simple
    matter to convert them.

    The interface provides two ways to calculate digests: all-at-once, or in
    stages. To illustrate, the following short program computes the SHA3-256
    digest of "hello world" using each approach:

            use Digest::SHA3 qw(sha3_256_hex);

            $data = "hello world";
            @frags = split(//, $data);

            # all-at-once (Functional style)
            $digest1 = sha3_256_hex($data);

            # in-stages (OOP style)
            $state = Digest::SHA3->new(256);
            for (@frags) { $state->add($_) }
            $digest2 = $state->hexdigest;

            print $digest1 eq $digest2 ?
                    "that's the ticket!\n" : "oops!\n";

    To calculate the digest of an n-bit message where *n* is not a multiple
    of 8, use the *add_bits()* method. For example, consider the 446-bit
    message consisting of the bit-string "110" repeated 148 times, followed
    by "11". Here's how to display its SHA3-512 digest:

            use Digest::SHA3;
            $bits = "110" x 148 . "11";
            $sha3 = Digest::SHA3->new(512)->add_bits($bits);
            print $sha3->hexdigest, "\n";

    Note that for larger bit-strings, it's more efficient to use the
    two-argument version *add_bits($data, $nbits)*, where *$data* is in the
    customary packed binary format used for Perl strings.

UNICODE AND SIDE EFFECTS
    Perl supports Unicode strings as of version 5.6. Such strings may
    contain wide characters: namely, characters whose ordinal values are
    greater than 255. This can cause problems for digest algorithms such as
    SHA-3 that are specified to operate on sequences of bytes.

    The rule by which Digest::SHA3 handles a Unicode string is easy to
    state, but potentially confusing to grasp: the string is interpreted as
    a sequence of byte values, where each byte value is equal to the ordinal
    value (viz. code point) of its corresponding Unicode character. That
    way, the Unicode string 'abc' has exactly the same digest value as the
    ordinary string 'abc'.

    Since a wide character does not fit into a byte, the Digest::SHA3
    routines croak if they encounter one. Whereas if a Unicode string
    contains no wide characters, the module accepts it quite happily. The
    following code illustrates the two cases:

            $str1 = pack('U*', (0..255));
            print sha3_224_hex($str1);              # ok

            $str2 = pack('U*', (0..256));
            print sha3_224_hex($str2);              # croaks

    Be aware that the digest routines silently convert UTF-8 input into its
    equivalent byte sequence in the native encoding (cf. utf8::downgrade).
    This side effect influences only the way Perl stores the data
    internally, but otherwise leaves the actual value of the data intact.

PADDING OF BASE64 DIGESTS
    By convention, CPAN Digest modules do not pad their Base64 output.
    Problems can occur when feeding such digests to other software that
    expects properly padded Base64 encodings.

    For the time being, any necessary padding must be done by the user.
    Fortunately, this is a simple operation: if the length of a
    Base64-encoded digest isn't a multiple of 4, simply append "="
    characters to the end of the digest until it is:

            while (length($b64_digest) % 4) {
                    $b64_digest .= '=';
            }

    To illustrate, *sha3_256_base64("abc")* is computed to be

            Ophdp0/iJbIEXBcta9OQvYVfCG4+nVJbRr/iRRFDFTI

    which has a length of 43. So, the properly padded version is

            Ophdp0/iJbIEXBcta9OQvYVfCG4+nVJbRr/iRRFDFTI=

EXPORT
    None by default.

EXPORTABLE FUNCTIONS
    Provided your C compiler supports a 64-bit type (e.g. the *long long* of
    C99, or *__int64* used by Microsoft C/C++), all of these functions will
    be available for use. Otherwise you won't be able to perform any of
    them.

    In the interest of simplicity, maintainability, and small code size,
    it's unlikely that future versions of this module will support a 32-bit
    implementation. Older platforms using 32-bit-only compilers should
    continue to favor 32-bit hash implementations such as SHA-1, SHA-224, or
    SHA-256. The desire to use the SHA-3 hash standard, dating from 2015,
    should reasonably require that one's compiler adhere to programming
    language standards dating from at least 1999.

    *Functional style*

    sha3_224($data, ...)
    sha3_256($data, ...)
    sha3_384($data, ...)
    sha3_512($data, ...)
    shake128($data, ...)
    shake256($data, ...)
        Logically joins the arguments into a single string, and returns its
        SHA3-0/224/256/384/512 digest encoded as a binary string.

        The digest size for shake128 is 1344 bits (168 bytes); for shake256,
        it's 1088 bits (136 bytes). To obtain extendable-output from the
        SHAKE algorithms, use the object-oriented interface with repeated
        calls to the *squeeze* method.

    sha3_224_hex($data, ...)
    sha3_256_hex($data, ...)
    sha3_384_hex($data, ...)
    sha3_512_hex($data, ...)
    shake128_hex($data, ...)
    shake256_hex($data, ...)
        Logically joins the arguments into a single string, and returns its
        SHA3-0/224/256/384/512 or SHAKE128/256 digest encoded as a
        hexadecimal string.

    sha3_224_base64($data, ...)
    sha3_256_base64($data, ...)
    sha3_384_base64($data, ...)
    sha3_512_base64($data, ...)
    shake128_base64($data, ...)
    shake256_base64($data, ...)
        Logically joins the arguments into a single string, and returns its
        SHA3-0/224/256/384/512 or SHAKE128/256 digest encoded as a Base64
        string.

        It's important to note that the resulting string does not contain
        the padding characters typical of Base64 encodings. This omission is
        deliberate, and is done to maintain compatibility with the family of
        CPAN Digest modules. See "PADDING OF BASE64 DIGESTS" for details.

    *OOP style*

    new($alg)
        Returns a new Digest::SHA3 object. Allowed values for *$alg* are
        224, 256, 384, and 512 for the SHA3 algorithms; or 128000 and 256000
        for SHAKE128 and SHAKE256, respectively. If the argument is missing,
        SHA3-224 will be used by default.

        Invoking *new* as an instance method will not create a new object;
        instead, it will simply reset the object to the initial state
        associated with *$alg*. If the argument is missing, the object will
        continue using the same algorithm that was selected at creation.

    reset($alg)
        This method has exactly the same effect as *new($alg)*. In fact,
        *reset* is just an alias for *new*.

    hashsize
        Returns the number of digest bits for this object. The values are
        224, 256, 384, 512, 1344, and 1088 for SHA3-224, SHA3-256, SHA3-384,
        SHA3-512, SHAKE128, and SHAKE256, respectively.

    algorithm
        Returns the digest algorithm for this object. The values are 224,
        256, 384, 512, 128000, and 256000 for SHA3-224, SHA3-256, SHA3-384,
        SHA3-512, SHAKE128, and SHAKE256, respectively.

    clone
        Returns a duplicate copy of the object.

    add($data, ...)
        Logically joins the arguments into a single string, and uses it to
        update the current digest state. In other words, the following
        statements have the same effect:

                $sha3->add("a"); $sha3->add("b"); $sha3->add("c");
                $sha3->add("a")->add("b")->add("c");
                $sha3->add("a", "b", "c");
                $sha3->add("abc");

        The return value is the updated object itself.

    add_bits($data, $nbits [, $lsb])
    add_bits($bits)
        Updates the current digest state by appending bits to it. The return
        value is the updated object itself.

        The first form causes the most-significant *$nbits* of *$data* to be
        appended to the stream. The *$data* argument is in the customary
        binary format used for Perl strings. Setting the optional *$lsb*
        flag to a true value indicates that the final (partial) byte of
        *$data* is aligned with the least-significant bit; by default it's
        aligned with the most-significant bit, as required by the parent
        Digest module.

        The second form takes an ASCII string of "0" and "1" characters as
        its argument. It's equivalent to

                $sha3->add_bits(pack("B*", $bits), length($bits));

        So, the following three statements do the same thing:

                $sha3->add_bits("111100001010");
                $sha3->add_bits("\xF0\xA0", 12);
                $sha3->add_bits("\xF0\x0A", 12, 1);

        SHA-3 uses least-significant-bit ordering for its internal
        operation. This means that

                $sha3->add_bits("110");

        is equivalent to

                $sha3->add_bits("0")->add_bits("1")->add_bits("1");

        Many public test vectors for SHA-3, such as the Keccak known-answer
        tests, are delivered in least-significant-bit format. Using the
        optional *$lsb* flag in these cases allows your code to be simpler
        and more efficient. See the test directory for examples.

        The fact that SHA-2 and SHA-3 employ opposite bit-ordering schemes
        has caused noticeable confusion in the programming community.
        Exercise caution if your code examines individual bits in data
        streams.

    addfile(*FILE)
        Reads from *FILE* until EOF, and appends that data to the current
        state. The return value is the updated object itself.

    addfile($filename [, $mode])
        Reads the contents of *$filename*, and appends that data to the
        current state. The return value is the updated object itself.

        By default, *$filename* is simply opened and read; no special modes
        or I/O disciplines are used. To change this, set the optional
        *$mode* argument to one of the following values:

                "b"     read file in binary mode

                "U"     use universal newlines

                "0"     use BITS mode

        The "U" mode is modeled on Python's "Universal Newlines" concept,
        whereby DOS and Mac OS line terminators are converted internally to
        UNIX newlines before processing. This ensures consistent digest
        values when working simultaneously across multiple file systems. The
        "U" mode influences only text files, namely those passing Perl's
        *-T* test; binary files are processed with no translation
        whatsoever.

        The BITS mode ("0") interprets the contents of *$filename* as a
        logical stream of bits, where each ASCII '0' or '1' character
        represents a 0 or 1 bit, respectively. All other characters are
        ignored. This provides a convenient way to calculate the digest
        values of partial-byte data by using files, rather than having to
        write programs using the *add_bits* method.

    digest
        Returns the digest encoded as a binary string.

        Note that the *digest* method is a read-once operation. Once it has
        been performed, the Digest::SHA3 object is automatically reset in
        preparation for calculating another digest value. Call
        *$sha->clone->digest* if it's necessary to preserve the original
        digest state.

    hexdigest
        Returns the digest encoded as a hexadecimal string.

        Like *digest*, this method is a read-once operation. Call
        *$sha->clone->hexdigest* if it's necessary to preserve the original
        digest state.

    b64digest
        Returns the digest encoded as a Base64 string.

        Like *digest*, this method is a read-once operation. Call
        *$sha->clone->b64digest* if it's necessary to preserve the original
        digest state.

        It's important to note that the resulting string does not contain
        the padding characters typical of Base64 encodings. This omission is
        deliberate, and is done to maintain compatibility with the family of
        CPAN Digest modules. See "PADDING OF BASE64 DIGESTS" for details.

    squeeze
        Returns the next 168 (136) bytes of the SHAKE128 (SHAKE256) digest
        encoded as a binary string. The *squeeze* method may be called
        repeatedly to construct digests of any desired length.

        This method is applicable only to SHAKE128 and SHAKE256 objects.

SEE ALSO
    Digest, Digest::SHA, Digest::Keccak

    The FIPS 202 SHA-3 Standard can be found at:

    <http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.202.pdf>

    The Keccak/SHA-3 specifications can be found at:

    <http://keccak.noekeon.org/Keccak-reference-3.0.pdf>
    <http://keccak.noekeon.org/Keccak-submission-3.pdf>

AUTHOR
            Mark Shelor     <mshelor AT cpan.org>

ACKNOWLEDGMENTS
    The author is particularly grateful to

            Guido Bertoni
            Joan Daemen
            Michael Peeters
            Chris Skiscim
            Gilles Van Assche

    "Nothing is more fatiguing nor, in the long run, more exasperating than
    the daily effort to believe things which daily become more incredible.
    To be done with this effort is an indispensible condition of secure and
    lasting happiness." - Bertrand Russell

COPYRIGHT AND LICENSE
    Copyright (C) 2012-2018 Mark Shelor

    This library is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

    perlartistic