122 lines
2.9 KiB
Markdown
122 lines
2.9 KiB
Markdown
# libft_ssl
|
|
|
|
A C library implementing cryptographic hash functions from scratch.
|
|
|
|
Each algorithm exposes a uniform streaming API — `init` / `update` / `final`
|
|
|
|
## Algorithms
|
|
|
|
| Algorithm | Digest | Block | Notes |
|
|
|------------|--------|-------|-------|
|
|
| MD5 | 128-bit | 512-bit | RFC 1321 - broken, non-security use only |
|
|
| SHA-256 | 256-bit | 512-bit | SHA-2 family, NSA/NIST - widely used in TLS, Bitcoin |
|
|
| Whirlpool | 512-bit | 512-bit | ISO/IEC 10118-3 - Miyaguchi-Preneel construction |
|
|
|
|
## API
|
|
|
|
The public interface lives in `<libft_ssl/libft_ssl.h>`.
|
|
|
|
```c
|
|
struct digest_algo {
|
|
const char *name;
|
|
size_t digest_size; /* bytes */
|
|
size_t block_size; /* bytes */
|
|
void (*init) (void *ctx);
|
|
void (*update)(void *ctx, const uint8_t *data, size_t len);
|
|
void (*final) (void *ctx, uint8_t *out);
|
|
};
|
|
|
|
union digest_ctx { /* one allocation covers all algorithm contexts */
|
|
struct md5_ctx md5;
|
|
struct sha256_ctx sha256;
|
|
struct whirlpool_ctx whirlpool;
|
|
};
|
|
```
|
|
|
|
One global instance is provided per algorithm: `g_md5`, `g_sha256`,
|
|
`g_whirlpool`.
|
|
|
|
### Example
|
|
|
|
```c
|
|
#include <libft_ssl/libft_ssl.h>
|
|
#include <stdio.h>
|
|
|
|
int main(void)
|
|
{
|
|
const struct digest_algo *algo = &g_sha256;
|
|
union digest_ctx ctx;
|
|
uint8_t digest[32];
|
|
|
|
algo->init(&ctx);
|
|
algo->update(&ctx, (const uint8_t *)"hello", 5);
|
|
algo->final(&ctx, digest);
|
|
|
|
for (size_t i = 0; i < algo->digest_size; i++)
|
|
printf("%02x", digest[i]);
|
|
puts("");
|
|
}
|
|
```
|
|
|
|
Compile with:
|
|
|
|
```sh
|
|
cc example.c -lft_ssl -o example
|
|
# or with pkg-config:
|
|
cc example.c $(pkg-config --cflags --libs libft_ssl) -o example
|
|
```
|
|
|
|
## Building
|
|
|
|
### Dependencies
|
|
|
|
- C99 compiler
|
|
- autoconf
|
|
- automake
|
|
- libtool
|
|
- `pdflatex` — only if building documentation (`--enable-doc`)
|
|
|
|
### Steps
|
|
|
|
```sh
|
|
./autogen.sh # generate the build system (first checkout only)
|
|
./configure
|
|
make
|
|
make install # installs to /usr/local by default
|
|
```
|
|
|
|
Common `configure` options:
|
|
|
|
| Flag | Default | Description |
|
|
|------|---------|-------------|
|
|
| `--prefix=PATH` | `/usr/local` | Installation prefix |
|
|
| `--enable-debug` | no | Build with `-g -O0` instead of `-O2` |
|
|
| `--enable-doc` | no | Build PDF documentation (requires `pdflatex`) |
|
|
|
|
### pkg-config
|
|
|
|
After installation the library registers itself with pkg-config:
|
|
|
|
```sh
|
|
pkg-config --cflags --libs libft_ssl
|
|
```
|
|
|
|
## Project structure
|
|
|
|
```
|
|
include/ public and internal headers
|
|
src/
|
|
md5/ MD5 init / update / compress / final
|
|
sha256/ SHA-256 init / update / compress / final
|
|
whirlpool/ Whirlpool init / update / compress / final
|
|
libft_ssl.c algorithm descriptor table (X-macro generated)
|
|
doc/ LaTeX source for the technical documentation
|
|
```
|
|
|
|
## Documentation
|
|
|
|
The full technical write-up is available at <https://lohic.dev/libft_ssl.html> ([PDF](https://lohic.dev/libft_ssl.pdf)).
|
|
|
|
## License
|
|
|
|
GPLv3 — see [LICENSE](LICENSE).
|