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add zig 0.15 crypto and testing notes
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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languages/ziglang/0.15/README.md
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languages/ziglang/0.15/README.md
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- [build](./build.md) - createModule + imports, hash trick
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- [comptime](./comptime.md) - type generation, tuple synthesis, validation
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- [concurrency](./concurrency.md) - atomics vs mutex, callback pattern
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- [crypto](./crypto.md) - ecdsa paths, signature verification
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- [testing](./testing.md) - zig test vs build test, arena for leaky apis
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languages/ziglang/0.15/crypto.md
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languages/ziglang/0.15/crypto.md
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# crypto
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zig 0.15 crypto paths and patterns.
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## ecdsa
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the ecdsa types are under `std.crypto.sign.ecdsa`, not `std.crypto.ecdsa`:
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```zig
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const crypto = std.crypto;
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// correct (0.15)
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const Secp256k1 = crypto.sign.ecdsa.EcdsaSecp256k1Sha256;
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const P256 = crypto.sign.ecdsa.EcdsaP256Sha256;
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// wrong - will error "has no member named 'ecdsa'"
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// const Secp256k1 = crypto.ecdsa.EcdsaSecp256k1Sha256;
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```
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## verifying signatures
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```zig
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const Scheme = std.crypto.sign.ecdsa.EcdsaSecp256k1Sha256;
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// signature is r || s (64 bytes for 256-bit curves)
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const sig = Scheme.Signature.fromBytes(sig_bytes[0..64].*);
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// public key from SEC1 compressed format (33 bytes)
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const public_key = try Scheme.PublicKey.fromSec1(key_bytes);
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// verify - returns error.SignatureVerificationFailed on mismatch
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try sig.verify(message, public_key);
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```
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## key sizes
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| curve | compressed pubkey | uncompressed pubkey | signature (r\|\|s) |
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|-------|-------------------|---------------------|-------------------|
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| P-256 | 33 bytes | 65 bytes | 64 bytes |
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| secp256k1 | 33 bytes | 65 bytes | 64 bytes |
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compressed keys start with 0x02 or 0x03. uncompressed start with 0x04.
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see: [zat/jwt.zig](https://tangled.sh/@zzstoatzz.io/zat/tree/main/src/internal/jwt.zig)
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languages/ziglang/0.15/testing.md
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languages/ziglang/0.15/testing.md
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# testing
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`zig build test` compiles tests but may not run them if your build.zig doesn't wire it up correctly. to actually run tests:
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```bash
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zig test src/foo.zig # runs tests in foo.zig and its imports
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zig test src/foo.zig --test-filter "parse" # only tests matching "parse"
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```
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the testing allocator catches leaks. if you use `parseFromValueLeaky` or similar "leaky" apis, wrap in an arena:
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```zig
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var arena = std.heap.ArenaAllocator.init(std.testing.allocator);
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defer arena.deinit();
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const result = try leakyFunction(arena.allocator(), input);
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```
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languages/ziglang/README.md
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## topics
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- [0.15](./0.15/) - version-specific patterns (i/o overhaul, arraylist, concurrency)
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- [0.15](./0.15/) - version-specific patterns (i/o, arraylist, crypto, testing)
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- [build](./build/) - build system patterns from large projects
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## sources
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| [find-bufo](https://tangled.sh/@zzstoatzz.io/find-bufo) | bluesky bot |
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| [leaflet-search](https://tangled.sh/@zzstoatzz.io/leaflet-search) | fts search backend |
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| [zql](https://tangled.sh/@zzstoatzz.io/zql) | comptime sql parsing |
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| [zat](https://tangled.sh/@zzstoatzz.io/zat) | atproto primitives (jwt, crypto) |
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| [ghostty](https://github.com/ghostty-org/ghostty) | terminal emulator (build system) |
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| [bun](https://github.com/oven-sh/bun) | javascript runtime (build system) |
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