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✏️ Editing: fingerprint.js

module.exports = Fingerprint;

var assert = require('assert-plus');
var Buffer = require('safer-buffer').Buffer;
var algs = require('./algs');
var crypto = require('crypto');
var errs = require('./errors');
var Key = require('./key');
var Certificate = require('./certificate');
var utils = require('./utils');

var FingerprintFormatError = errs.FingerprintFormatError;
var InvalidAlgorithmError = errs.InvalidAlgorithmError;

function Fingerprint(opts) {
	assert.object(opts, 'options');
	assert.string(opts.type, 'options.type');
	assert.buffer(opts.hash, 'options.hash');
	assert.string(opts.algorithm, 'options.algorithm');

this.algorithm = opts.algorithm.toLowerCase();
	if (algs.hashAlgs[this.algorithm] !== true)
		throw (new InvalidAlgorithmError(this.algorithm));

this.hash = opts.hash;
	this.type = opts.type;
}

Fingerprint.prototype.toString = function (format) {
	if (format === undefined) {
		if (this.algorithm === 'md5')
			format = 'hex';
		else
			format = 'base64';
	}
	assert.string(format);

switch (format) {
	case 'hex':
		return (addColons(this.hash.toString('hex')));
	case 'base64':
		return (sshBase64Format(this.algorithm,
		    this.hash.toString('base64')));
	default:
		throw (new FingerprintFormatError(undefined, format));
	}
};

Fingerprint.prototype.matches = function (other) {
	assert.object(other, 'key or certificate');
	if (this.type === 'key') {
		utils.assertCompatible(other, Key, [1, 0], 'key');
	} else {
		utils.assertCompatible(other, Certificate, [1, 0],
		    'certificate');
	}

var theirHash = other.hash(this.algorithm);
	var theirHash2 = crypto.createHash(this.algorithm).
	    update(theirHash).digest('base64');

if (this.hash2 === undefined)
		this.hash2 = crypto.createHash(this.algorithm).
		    update(this.hash).digest('base64');

return (this.hash2 === theirHash2);
};

Fingerprint.parse = function (fp, options) {
	assert.string(fp, 'fingerprint');

var alg, hash, enAlgs;
	if (Array.isArray(options)) {
		enAlgs = options;
		options = {};
	}
	assert.optionalObject(options, 'options');
	if (options === undefined)
		options = {};
	if (options.enAlgs !== undefined)
		enAlgs = options.enAlgs;
	assert.optionalArrayOfString(enAlgs, 'algorithms');

if (alg === undefined)
		throw (new FingerprintFormatError(fp));

if (algs.hashAlgs[alg] === undefined)
		throw (new InvalidAlgorithmError(alg));

if (enAlgs !== undefined) {
		enAlgs = enAlgs.map(function (a) { return a.toLowerCase(); });
		if (enAlgs.indexOf(alg) === -1)
			throw (new InvalidAlgorithmError(alg));
	}

return (new Fingerprint({
		algorithm: alg,
		hash: hash,
		type: options.type || 'key'
	}));
};

function addColons(s) {
	/*JSSTYLED*/
	return (s.replace(/(.{2})(?=.)/g, '$1:'));
}

function base64Strip(s) {
	/*JSSTYLED*/
	return (s.replace(/=*$/, ''));
}

function sshBase64Format(alg, h) {
	return (alg.toUpperCase() + ':' + base64Strip(h));
}

Fingerprint.isFingerprint = function (obj, ver) {
	return (utils.isCompatible(obj, Fingerprint, ver));
};

/*
 * API versions for Fingerprint:
 * [1,0] -- initial ver
 * [1,1] -- first tagged ver
 */
Fingerprint.prototype._sshpkApiVersion = [1, 1];

Fingerprint._oldVersionDetect = function (obj) {
	assert.func(obj.toString);
	assert.func(obj.matches);
	return ([1, 0]);
};

MR SKB