4 ms·

It's not made easier by the fact that a lot of cryptography is either very old and arcane or it's one hell of a mess of code that doesn't make sense without rea

It's not made easier by the fact that a lot of cryptography is either very old and arcane or it's one hell of a mess of code that doesn't make sense without reading standards. I had the misfortune of having to dig deep into constructing ASN.1 payloads by hand [1] because that's the only thing Java speaks, and oh holy hell is this A MESS because OF COURSE there's two ways to encode a bunch of bytes (BIT STRING vs OCTET STRING) and encoding ed25519 keys uses BOTH [2]. And ed25519 is a mess in itself. The more-or-less standard implementation by orlp [3] is almost completely lacking any comments explaining what is going on where and reading the relevant RFCs alone doesn't help, it's probably only understandable by reading a 500 pages math paper. It's almost as if cryptographers have zero interest in interested random people to join the field. End of rant. [1] https://github.com/msmuenchen/meshcore-packets-java/blob/main/src/main/java/de/afa_amateurfunk/meshcore_packets/crypto/PublicKey.java#L57 https://github.com/msmuenchen/meshcore-packets-java/blob/mai... [2] https://datatracker.ietf.org/doc/html/rfc8410#appendix-A https://datatracker.ietf.org/doc/html/rfc8410#appendix-A [3] https://github.com/orlp/ed25519/tree/master https://github.com/orlp/ed25519/tree/master

cyberax 6mo ago
X.509 is a deep legacy, but at least at this point it's well tested. > because that's the only thing Java speaks No, it most definitely is not. You can just construct a private key directly in BouncyCastle: https://downloads.bouncycastle.org/java/docs/bcprov-jdk18on-javadoc/org/bouncycastle/crypto/params/X25519PrivateKeyParameters.html https://downloads.bouncycastle.org/java/docs/bcprov-jdk18on-... I'm 100% certain that you also can do that with raw java.security. I did that about 15 years ago with raw RSA/EC keys. You can just directly specify the private exponent for RSA (as a bigint!) or the curve point for EC. Ditto for ed25519, you can just take the canonical implementation from DJB. And you really really shouldn't do that anyway, please just use OpenSSL or another similar major crypto library.
- Muromec 6mo ago
  I wouldn't recommend touching openssl (the library, command line tools are okay-ish) with anything that breaths life.
- mschuster91 6mo ago
  > I'm 100% certain that you also can do that with raw java.security. I tried that, the problem is Meshcore specific - they do their own weird shit with private and public keys [1]. Haven't figured out how to do the private key import either, because in the C source code (or in python re-implementations) Meshcore just calls directly into the raw ed25519 library to do their custom math... it's a mess. [1] https://jacksbrain.com/2026/01/a-hitchhiker-s-guide-to-meshcore-cryptography/ https://jacksbrain.com/2026/01/a-hitchhiker-s-guide-to-meshc...
  - cyberax 6mo ago
    I'm playing with LORA/Meshcore right now (I have an nRF52840 lying around). I'm pretty sure I know how to do that, will take a look.
tptacek 6mo ago
The typical vector for entering cryptography as a professional is called "grad school".
Muromec 6mo ago
The trick to asn.1 is to generate both parser and serializer from the spec. Elliptic curve math on the other hand is ... yeah, you need to know the math and also know the tricks to code that implements it. Both of those have steep learning curve, but it's hardly because it's a mess or it's old.
- mschuster91 6mo ago
  > Both of those have steep learning curve, but it's hardly because it's a mess or it's old. Bitpacking structures used to be important in the 60s. That time has passed, unless you're dealing with LoRa, NFC or other cases of highly constrained bandwidth there are way better options to serialize and deserialize information. It's time to move on, and the complexity of all the legacy garbage in crypto has been the case of many a security vulnerability in the past. As for the code, it might be personal preference but I'd love to have at least some comments referring back to a specification or original research paper in the code.
  - Avamander 6mo ago
    ASN.1 is not used because of just bitpacking. There are other benefits to ASN.1 and it's probably one of the least problematic parts there. People who have thought they can do better have made things like PGP. It's one of the worst cryptographic solutions out there. You're free to try as well though.
    - Muromec 6mo ago
      People who though they can do better did JWT, that is not complicated at all and has no bugs as well. Also solves 20% of what asn.1 is used for.
      - thayne 6mo ago
        Maybe a bit pedantic, but it would actually be the more general JOSE which includes tokens (JWT), signatures (JWS), and key transmission (JWK). And there is a related binary format that uses CBOR (COSE) as well.

cyberax 6mo ago

X.509 is a deep legacy, but at least at this point it's well tested. > because that's the only thing Java speaks No, it most definitely is not. You can just construct a private key directly in BouncyCastle: https://downloads.bouncycastle.org/java/docs/bcprov-jdk18on-javadoc/org/bouncycastle/crypto/params/X25519PrivateKeyParameters.html https://downloads.bouncycastle.org/java/docs/bcprov-jdk18on-... I'm 100% certain that you also can do that with raw java.security. I did that about 15 years ago with raw RSA/EC keys. You can just directly specify the private exponent for RSA (as a bigint!) or the curve point for EC. Ditto for ed25519, you can just take the canonical implementation from DJB. And you really really shouldn't do that anyway, please just use OpenSSL or another similar major crypto library.

Muromec 6mo ago
I wouldn't recommend touching openssl (the library, command line tools are okay-ish) with anything that breaths life.
mschuster91 6mo ago
> I'm 100% certain that you also can do that with raw java.security. I tried that, the problem is Meshcore specific - they do their own weird shit with private and public keys [1]. Haven't figured out how to do the private key import either, because in the C source code (or in python re-implementations) Meshcore just calls directly into the raw ed25519 library to do their custom math... it's a mess. [1] https://jacksbrain.com/2026/01/a-hitchhiker-s-guide-to-meshcore-cryptography/ https://jacksbrain.com/2026/01/a-hitchhiker-s-guide-to-meshc...
- cyberax 6mo ago
  I'm playing with LORA/Meshcore right now (I have an nRF52840 lying around). I'm pretty sure I know how to do that, will take a look.

tptacek 6mo ago

The typical vector for entering cryptography as a professional is called "grad school".

Muromec 6mo ago

The trick to asn.1 is to generate both parser and serializer from the spec. Elliptic curve math on the other hand is ... yeah, you need to know the math and also know the tricks to code that implements it. Both of those have steep learning curve, but it's hardly because it's a mess or it's old.

mschuster91 6mo ago
> Both of those have steep learning curve, but it's hardly because it's a mess or it's old. Bitpacking structures used to be important in the 60s. That time has passed, unless you're dealing with LoRa, NFC or other cases of highly constrained bandwidth there are way better options to serialize and deserialize information. It's time to move on, and the complexity of all the legacy garbage in crypto has been the case of many a security vulnerability in the past. As for the code, it might be personal preference but I'd love to have at least some comments referring back to a specification or original research paper in the code.
- Avamander 6mo ago
  ASN.1 is not used because of just bitpacking. There are other benefits to ASN.1 and it's probably one of the least problematic parts there. People who have thought they can do better have made things like PGP. It's one of the worst cryptographic solutions out there. You're free to try as well though.
  - Muromec 6mo ago
    People who though they can do better did JWT, that is not complicated at all and has no bugs as well. Also solves 20% of what asn.1 is used for.
    - thayne 6mo ago
      Maybe a bit pedantic, but it would actually be the more general JOSE which includes tokens (JWT), signatures (JWS), and key transmission (JWK). And there is a related binary format that uses CBOR (COSE) as well.