source: trip-planner-front/node_modules/sshpk/lib/formats/putty.js@ 76712b2

// Copyright 2018 Joyent, Inc.

module.exports = {
        read: read,
        write: write
};

var assert = require('assert-plus');
var Buffer = require('safer-buffer').Buffer;
var rfc4253 = require('./rfc4253');
var Key = require('../key');

var errors = require('../errors');

function read(buf, options) {
        var lines = buf.toString('ascii').split(/[\r\n]+/);
        var found = false;
        var parts;
        var si = 0;
        while (si < lines.length) {
                parts = splitHeader(lines[si++]);
                if (parts &&
                    parts[0].toLowerCase() === 'putty-user-key-file-2') {
                        found = true;
                        break;
                }
        }
        if (!found) {
                throw (new Error('No PuTTY format first line found'));
        }
        var alg = parts[1];

        parts = splitHeader(lines[si++]);
        assert.equal(parts[0].toLowerCase(), 'encryption');

        parts = splitHeader(lines[si++]);
        assert.equal(parts[0].toLowerCase(), 'comment');
        var comment = parts[1];

        parts = splitHeader(lines[si++]);
        assert.equal(parts[0].toLowerCase(), 'public-lines');
        var publicLines = parseInt(parts[1], 10);
        if (!isFinite(publicLines) || publicLines < 0 ||
            publicLines > lines.length) {
                throw (new Error('Invalid public-lines count'));
        }

        var publicBuf = Buffer.from(
            lines.slice(si, si + publicLines).join(''), 'base64');
        var keyType = rfc4253.algToKeyType(alg);
        var key = rfc4253.read(publicBuf);
        if (key.type !== keyType) {
                throw (new Error('Outer key algorithm mismatch'));
        }
        key.comment = comment;
        return (key);
}

function splitHeader(line) {
        var idx = line.indexOf(':');
        if (idx === -1)
                return (null);
        var header = line.slice(0, idx);
        ++idx;
        while (line[idx] === ' ')
                ++idx;
        var rest = line.slice(idx);
        return ([header, rest]);
}

function write(key, options) {
        assert.object(key);
        if (!Key.isKey(key))
                throw (new Error('Must be a public key'));

        var alg = rfc4253.keyTypeToAlg(key);
        var buf = rfc4253.write(key);
        var comment = key.comment || '';

        var b64 = buf.toString('base64');
        var lines = wrap(b64, 64);

        lines.unshift('Public-Lines: ' + lines.length);
        lines.unshift('Comment: ' + comment);
        lines.unshift('Encryption: none');
        lines.unshift('PuTTY-User-Key-File-2: ' + alg);

        return (Buffer.from(lines.join('\n') + '\n'));
}

function wrap(txt, len) {
        var lines = [];
        var pos = 0;
        while (pos < txt.length) {
                lines.push(txt.slice(pos, pos + 64));
                pos += 64;
        }
        return (lines);
}