| .. | ||
| argon2 | ||
| ge-additions | ||
| .gitignore | ||
| aes_cbc.c | ||
| aes_ecb.c | ||
| aes_siv.c | ||
| argon.c | ||
| BUILD.bazel | ||
| ed25519.c | ||
| ge_additions.c | ||
| keccak.c | ||
| README.md | ||
| ripemd.c | ||
| scrypt.c | ||
| secp256k1.c | ||
| sha.c | ||
| urcrypt.h | ||
| util.c | ||
| util.h | ||
What is urcrypt?
urcrypt is a library of cryptography routines used by urbit jets.
Why is urcrypt?
Urbit's C runtime (long the only urbit runtime) has accumulated a collection of cryptography dependencies, some with custom additions or patches. These libraries have different conventions and have been managed by u3 in an ad-hoc manner. Reproducing that arrangement in other runtimes is tricky and error-prone. The (sometimes inconsistent) logic must be reproduced and suitable cryptography primitives must be found (or worse, written) for the new environment.
To ease these burdens, urcrypt isolates the quirks behind a consistent calling convention. Everything is a little-endian byte array, and each jetted operation has a corresponding function in the library. Jets simply unpack their nouns, call urcrypt, and pack the results.
What is a cryptography routine?
This is more of a subjective question than it might appear. Any of the following conditions are sufficient, but not necessary, for a function to be included in urcrypt:
- The routine is sensitive to side-channel attacks (encryption, etc)
- Some property of the routine is cryptographically useful (SHA, RIPE, etc)
- The routine typically lives in a crypto library, for whatever reason.
A word on OpenSSL
It is the library user's responsibility to initialize openssl, set custom memory functions, etc.