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        {
            "type": "text",
            "text": "# Crypt::DH::GMP (perldoc)\n\n## NAME\n\nCrypt::DH::GMP - Crypt::DH Using GMP Directly\n\n## SYNOPSIS\n\nuse Crypt::DH::GMP;\nmy $dh = Crypt::DH::GMP->new(p => $p, g => $g);\nmy $val = $dh->computesecret();\n# If you want compatibility with Crypt::DH (it uses Math::BigInt)\n# then use this flag\n# You /think/ you're using Crypt::DH, but...\nuse Crypt::DH::GMP qw(-compat);\nmy $dh = Crypt::DH->new(p => $p, g => $g);\nmy $val = $dh->computesecret();\n\n## DESCRIPTION\n\nCrypt::DH::GMP is a (somewhat) portable replacement to Crypt::DH, implemented mostly in C.\n\n## Sections\n\n- **NAME**\n- **SYNOPSIS**\n- **DESCRIPTION**\n- **RATIONALE**\n- **BENCHMARK**\n- **METHODS**\n- **AUTHOR**\n- **LICENSE**\n\nUse structuredContent.sections for detailed options, examples, and full documentation.\n"
        }
    ],
    "structuredContent": {
        "command": "Crypt::DH::GMP",
        "section": "",
        "mode": "perldoc",
        "summary": "Crypt::DH::GMP - Crypt::DH Using GMP Directly",
        "synopsis": "use Crypt::DH::GMP;\nmy $dh = Crypt::DH::GMP->new(p => $p, g => $g);\nmy $val = $dh->computesecret();\n# If you want compatibility with Crypt::DH (it uses Math::BigInt)\n# then use this flag\n# You /think/ you're using Crypt::DH, but...\nuse Crypt::DH::GMP qw(-compat);\nmy $dh = Crypt::DH->new(p => $p, g => $g);\nmy $val = $dh->computesecret();",
        "tldr_summary": null,
        "tldr_examples": [],
        "tldr_source": null,
        "flags": [],
        "examples": [],
        "see_also": [],
        "section_outline": [
            {
                "name": "NAME",
                "lines": 2,
                "subsections": []
            },
            {
                "name": "SYNOPSIS",
                "lines": 13,
                "subsections": []
            },
            {
                "name": "DESCRIPTION",
                "lines": 2,
                "subsections": []
            },
            {
                "name": "RATIONALE",
                "lines": 44,
                "subsections": []
            },
            {
                "name": "BENCHMARK",
                "lines": 18,
                "subsections": []
            },
            {
                "name": "METHODS",
                "lines": 15,
                "subsections": []
            },
            {
                "name": "AUTHOR",
                "lines": 2,
                "subsections": []
            },
            {
                "name": "LICENSE",
                "lines": 5,
                "subsections": []
            }
        ],
        "sections": {
            "NAME": {
                "content": "Crypt::DH::GMP - Crypt::DH Using GMP Directly\n",
                "subsections": []
            },
            "SYNOPSIS": {
                "content": "use Crypt::DH::GMP;\n\nmy $dh = Crypt::DH::GMP->new(p => $p, g => $g);\nmy $val = $dh->computesecret();\n\n# If you want compatibility with Crypt::DH (it uses Math::BigInt)\n# then use this flag\n# You /think/ you're using Crypt::DH, but...\nuse Crypt::DH::GMP qw(-compat);\n\nmy $dh = Crypt::DH->new(p => $p, g => $g);\nmy $val = $dh->computesecret();\n",
                "subsections": []
            },
            "DESCRIPTION": {
                "content": "Crypt::DH::GMP is a (somewhat) portable replacement to Crypt::DH, implemented mostly in C.\n",
                "subsections": []
            },
            "RATIONALE": {
                "content": "In the beginning, there was \"Crypt::DH\". However, \"Crypt::DH\" suffers from a couple of problems:\n\nGMP/Pari libraries are almost always required\n\"Crypt::DH\" works with a plain \"Math::BigInt\", but if you want to use it in production, you\nalmost always need to install \"Math::BigInt::GMP\" or \"Math::BigInt::Pari\" because without\nthem, the computation that is required by \"Crypt::DH\" makes the module pretty much unusable.\n\nBecause of this, \"Crypt::DH\" might as well make \"Math::BigInt::GMP\" a hard requirement.\n\nCrypt::DH suffers from having Math::BigInt in between GMP\nWith or without \"Math::BigInt::GMP\" or \"Math::BigInt::Pari\", \"Crypt::DH\" makes several round\ntrip conversions between Perl scalars, Math::BigInt objects, and finally its C\nrepresentation (if GMP/Pari are installed).\n\nInstantiating an object comes with a relatively high cost, and if you make many computations\nin one go, your program will suffer dramatically because of this.\n\nThese problems quickly become apparent when you use modules such as \"Net::OpenID::Consumer\",\nwhich requires to make a few calls to \"Crypt::DH\".\n\n\"Crypt::DH::GMP\" attempts to alleviate these problems by providing a \"Crypt::DH\"-compatible\nlayer, which, instead of doing calculations via Math::BigInt, directly works with libgmp in C.\n\nThis means that we've essentially eliminated 2 call stacks worth of expensive Perl method calls\nand we also only load 1 (Crypt::DH::GMP) module instead of 3 (Crypt::DH + Math::BigInt +\nMath::BigInt::GMP).\n\nThese add up to a fairly significant increase in performance.\n\nCOMPATIBILITY WITH Crypt::DH\nCrypt::DH::GMP absolutely refuses to consider using anything other than strings as its\nparameters and/or return values therefore if you would like to use Math::BigInt objects as your\nreturn values, you can not use Crypt::DH::GMP directly. Instead, you need to be explicit about\nit:\n\nuse Crypt::DH;\nuse Crypt::DH::GMP qw(-compat); # must be loaded AFTER Crypt::DH\n\nSpecifying -compat invokes a very nasty hack that overwrites Crypt::DH's symbol table -- this\nthen forces Crypt::DH users to use Crypt::DH::GMP instead, even if you are writing\n\nmy $dh = Crypt::DH->new(...);\n$dh->computekey();\n",
                "subsections": []
            },
            "BENCHMARK": {
                "content": "By NO MEANS is this an exhaustive benchmark, but here's what I get on my MacBook (OS X 10.5.8,\n2.4 GHz Core 2 Duo, 4GB RAM)\n\nBenchmarking instatiation cost...\nRate   pp  gmp\npp   9488/s   -- -79%\ngmp 45455/s 379%   --\n\nBenchmarking key generation cost...\nRate gmp  pp\ngmp 6.46/s  -- -0%\npp  6.46/s  0%  --\n\nBenchmarking computekey cost...\nRate    pp   gmp\npp   12925/s    --  -96%\ngmp 365854/s 2730%    --\n",
                "subsections": []
            },
            "METHODS": {
                "content": "new\np\ng\ncomputekey\ncomputesecret\ngeneratekeys\npubkey\nprivkey\ncomputekeytwoc\nComputes the key, and returns a string that is byte-padded two's compliment in binary form.\n\npubkeytwoc\nReturns the pubkey as a string that is byte-padded two's compliment in binary form.\n\nclone",
                "subsections": []
            },
            "AUTHOR": {
                "content": "Daisuke Maki \"<daisuke@endeworks.jp>\"\n",
                "subsections": []
            },
            "LICENSE": {
                "content": "This program is free software; you can redistribute it and/or modify it under the same terms as\nPerl itself.\n\nSee http://www.perl.com/perl/misc/Artistic.html\n",
                "subsections": []
            }
        }
    }
}