2021-11-03 -- LuaNacha is deprecated. It is replaced by LuaMonocypher, a cleaner and up to date Lua wrapper for the Monocypher cryptographic C library by Loup Vaillant.
The Monocypher library is included here (currently version 2.0.5)
Monocypher is itself heavily based on the NaCl crypto library by Daniel Bernstein and Tanja Lange.
Major features and differences with the NaCl library:
- Authenticated encryption with Chacha20 stream encryption (more precisely Xchacha20, ie. Chacha with a 24-byte nonce) and Poly1305 MAC,
- Curve25519-based key exchange and public key encryption,
- Blake2b hash function,
- Ed25519-based signature function using Blake2b hash instead of sha512,
- Argon2i, a modern key derivation function based on Blake2b. Like scrypt, it is designed to be expensive in both CPU and memory.
The complete documentation of the Monocypher library is available at http://loup-vaillant.fr/projects/monocypher/manual
Note: As of August 2017, Monocypher is deemed to be production-ready. (See section "Current state" at http://loup-vaillant.fr/projects/monocypher/)
The Lua wrapper
It includes an interface to an OS random generator (for the moment only based on /dev/urandom and tested on Linux)
The functions keep as much as possible the same name as in Monocypher (without the "crypto_" prefix) and the same parameter order.
LuaNacha API summary:
randombytes(n) return a string containing n random bytes --- Authenticated encryption lock(key, nonce, plain [, prefix]) => crypted authenticated encryption using Xchacha20 and a Poly1305 MAC key must be a 32-byte string nonce must be a 24-byte string plain is the text to encrypt as a string prefix is an optional string. If it is provided, it is prepended to the encrypted text. The prefix can be use for example to store the nonce, and avoid extra string allocation and copying in Lua applications. The prefix defaults to the empty string. Return the encrypted text as a string. The encrypted text includes the 16-byte MAC. So #crypted == #plain + 16 + #prefix Note: the prefix is not an "additional data" in the AEAD sense. The MAC is computed over only the encrypted text. It does not include the prefix. unlock(key, nonce, crypted [, offset]) => plain authenticated decryption - verification of the Poly1305 MAC and decryption with Xcahcha20. key must be a 32-byte string nonce must be a 24-byte string crypted is the text to decrypt as a string offset is an optional integer. It is the length of the prefix used by lock() if any. It defaults to 0. Return the decrypted text as a string or nil if the MAC verification fails. Note: the responsibility of using matching prefix and offset belongs to the application. --- Curve25519-based key exchange public_key(sk) => pk return the public key associated to a curve25519 secret key sk is the secret key as a 32-byte string pk is the associated public key as a 32-byte string keypair() => pk, sk generates a pair of curve25519 keys (public key, secret key) pk is the public key as a 32-byte string sk is the secret key as a 32-byte string Note: This is a convenience function: pk, sk = keypair() --is equivalent to sk = randombytes(32); pk = public_key(sk) key_exchange(sk, pk) => k DH key exchange. Return a session key k used to encrypt or decrypt a text. sk is the secret key of the party invoking the function ("our secret key"). pk is the public key of the other party ("their public key"). sk, pk and k are 32-byte strings --- Blake2b cryptographic hash blake2b_init([digest_size [, key]]) => ctx initialize and return a blake2b context object digest_size is the optional length of the expected digest. If provided, it must be an integer between 1 and 64. It defaults to 64. key is an optional key allowing to use blake2b as a MAC function. If provided, key is a string with a length that must be between 1 and 64. The default is no key. ctx is a pointer to the blake2b context as a light userdata. blake2b_update(ctx, text_fragment) update the hash with a new text fragment ctx is a pointer to a blake2b context as a light userdata. blake2b_final(ctx) => digest return the final value of the hash ctx is a pointer to a blake2b context as a light userdata. The digest is returned as a string. The length of the digest has been defined at the context creation (see blake2b_init()). It defaults to 64. blake2b(text) => digest compute the hash of a string. Returns a 64-byte digest. This is a convenience function which combines the init(), update() and final() functions above. --- Ed25519 signature sign_public_key(sk) => pk return the public key associated to a secret key sk is the secret key as a 32-byte string pk is the associated public key as a 32-byte string sign_keypair() => pk, sk generates a pair of ed25519 signature keys (public key, secret key) pk is the public signature key as a 32-byte string sk is the secret signature key as a 32-byte string Note: This is a convenience function: pk, sk = sign_keypair() --is equivalent to sk = randombytes(32); pk = sign_public_key(sk) sign(sk, text) => sig sign a text with a secret key sk is the secret key as a 32-byte string text is the text to sign as a string Return the text signature as a 64-byte string. check(sig, pk, text) => is_valid check a text signature with a public key sig is the signature to verify, as a 64-byte string pk is the public key as a 32-byte string text is the signed text Return a boolean indicating if the signature is valid or not. Note: curve25519 key pairs (generated with keypair()) cannot be used for ed25519 signature. The signature key pairs must be generated with sign_keypair(). --- Argon2i password derivation argon2i(pw, salt, nkb, niter) => k compute a key given a password and some salt This is a password key derivation function similar to scrypt. It is intended to make derivation expensive in both CPU and memory. pw: the password string salt: some entropy as a string (typically 16 bytes) nkb: number of kilobytes used in RAM (as large as possible) niter: number of iterations (as large as possible, >= 10) Return k, a key string (32 bytes). For example: on a CPU i5 M430 @ 2.27 GHz laptop, with nkb=100000 (100MB) and niter=10, the derivation takes ~ 1.8 sec Note: this implementation has no threading support, so no parallel execution.
Adjust the Makefile according to your Lua installation.
make -- build luanacha.so make test -- build luanacha.so if needed, then run test/test_luanacha.lua make clean make LUA=/path/to/lua LUAINC=/path/to/lua_include_dir test
Yes, a rockspec is due :-)
The original Monocypher source code is licensed under the following terms (from the monocypher README file):
Monocypher is dual-licensed. Choose whichever you want. The first licence is a regular 2-clause BSD licence. The second licence is the CC-0 from Creative Commons. It is intended to release Monocypher to the public domain. The BSD licence serves as a fallback. Licence 1 (2-clause BSD) ------------------------ Copyright (c) 2017, Loup Vaillant All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Licence 2 (CC-0) ---------------- > CREATIVE COMMONS CORPORATION IS NOT A LAW FIRM AND DOES NOT PROVIDE > LEGAL SERVICES. DISTRIBUTION OF THIS DOCUMENT DOES NOT CREATE AN > ATTORNEY-CLIENT RELATIONSHIP. CREATIVE COMMONS PROVIDES THIS > INFORMATION ON AN "AS-IS" BASIS. CREATIVE COMMONS MAKES NO WARRANTIES > REGARDING THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS > PROVIDED HEREUNDER, AND DISCLAIMS LIABILITY FOR DAMAGES RESULTING FROM > THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS PROVIDED > HEREUNDER. ### Statement of Purpose The laws of most jurisdictions throughout the world automatically confer exclusive Copyright and Related Rights (defined below) upon the creator and subsequent owner(s) (each and all, an "owner") of an original work of authorship and/or a database (each, a "Work"). Certain owners wish to permanently relinquish those rights to a Work for the purpose of contributing to a commons of creative, cultural and scientific works ("Commons") that the public can reliably and without fear of later claims of infringement build upon, modify, incorporate in other works, reuse and redistribute as freely as possible in any form whatsoever and for any purposes, including without limitation commercial purposes. These owners may contribute to the Commons to promote the ideal of a free culture and the further production of creative, cultural and scientific works, or to gain reputation or greater distribution for their Work in part through the use and efforts of others. For these and/or other purposes and motivations, and without any expectation of additional consideration or compensation, the person associating CC0 with a Work (the "Affirmer"), to the extent that he or she is an owner of Copyright and Related Rights in the Work, voluntarily elects to apply CC0 to the Work and publicly distribute the Work under its terms, with knowledge of his or her Copyright and Related Rights in the Work and the meaning and intended legal effect of CC0 on those rights. 1. **Copyright and Related Rights.** A Work made available under CC0 may be protected by copyright and related or neighboring rights ("Copyright and Related Rights"). Copyright and Related Rights include, but are not limited to, the following: - the right to reproduce, adapt, distribute, perform, display, communicate, and translate a Work; - moral rights retained by the original author(s) and/or performer(s); publicity and privacy rights pertaining to a person's image or likeness depicted in a Work; - rights protecting against unfair competition in regards to a Work, subject to the limitations in paragraph 4(a), below; - rights protecting the extraction, dissemination, use and reuse of data in a Work; - database rights (such as those arising under Directive 96/9/EC of the European Parliament and of the Council of 11 March 1996 on the legal protection of databases, and under any national implementation thereof, including any amended or successor version of such directive); and - other similar, equivalent or corresponding rights throughout the world based on applicable law or treaty, and any national implementations thereof. 2. **Waiver.** To the greatest extent permitted by, but not in contravention of, applicable law, Affirmer hereby overtly, fully, permanently, irrevocably and unconditionally waives, abandons, and surrenders all of Affirmer's Copyright and Related Rights and associated claims and causes of action, whether now known or unknown (including existing as well as future claims and causes of action), in the Work (i) in all territories worldwide, (ii) for the maximum duration provided by applicable law or treaty (including future time extensions), (iii) in any current or future medium and for any number of copies, and (iv) for any purpose whatsoever, including without limitation commercial, advertising or promotional purposes (the "Waiver"). Affirmer makes the Waiver for the benefit of each member of the public at large and to the detriment of Affirmer's heirs and successors, fully intending that such Waiver shall not be subject to revocation, rescission, cancellation, termination, or any other legal or equitable action to disrupt the quiet enjoyment of the Work by the public as contemplated by Affirmer's express Statement of Purpose. 3. **Public License Fallback.** Should any part of the Waiver for any reason be judged legally invalid or ineffective under applicable law, then the Waiver shall be preserved to the maximum extent permitted taking into account Affirmer's express Statement of Purpose. In addition, to the extent the Waiver is so judged Affirmer hereby grants to each affected person a royalty-free, non transferable, non sublicensable, non exclusive, irrevocable and unconditional license to exercise Affirmer's Copyright and Related Rights in the Work (i) in all territories worldwide, (ii) for the maximum duration provided by applicable law or treaty (including future time extensions), (iii) in any current or future medium and for any number of copies, and (iv) for any purpose whatsoever, including without limitation commercial, advertising or promotional purposes (the "License"). The License shall be deemed effective as of the date CC0 was applied by Affirmer to the Work. Should any part of the License for any reason be judged legally invalid or ineffective under applicable law, such partial invalidity or ineffectiveness shall not invalidate the remainder of the License, and in such case Affirmer hereby affirms that he or she will not (i) exercise any of his or her remaining Copyright and Related Rights in the Work or (ii) assert any associated claims and causes of action with respect to the Work, in either case contrary to Affirmer's express Statement of Purpose. 4. **Limitations and Disclaimers.** - No trademark or patent rights held by Affirmer are waived, abandoned, surrendered, licensed or otherwise affected by this document. - Affirmer offers the Work as-is and makes no representations or warranties of any kind concerning the Work, express, implied, statutory or otherwise, including without limitation warranties of title, merchantability, fitness for a particular purpose, non infringement, or the absence of latent or other defects, accuracy, or the present or absence of errors, whether or not discoverable, all to the greatest extent permissible under applicable law. - Affirmer disclaims responsibility for clearing rights of other persons that may apply to the Work or any use thereof, including without limitation any person's Copyright and Related Rights in the Work. Further, Affirmer disclaims responsibility for obtaining any necessary consents, permissions or other rights required for any use of the Work. - Affirmer understands and acknowledges that Creative Commons is not a party to this document and has no duty or obligation with respect to this CC0 or use of the Work.
The luamonocypher wrapper library is MIT-licensed.