add lfcrypto, base64

docs/crypto.md

@@ -0,0 +1,24 @@
+# crypto
+
+Cryptographic library
+
+## Functions
+
+### b64_encode
+
+Encodes an `unsigned char *` into base64. User is responsible for freeing the 
+`char *` that is returned.
+
+```c
+char *b64_encode(const unsigned char *s, size_t sz);
+```
+
+### b64_decode
+
+Decodes a base64 encoded set of bytes into an `unsigned char *`. User is responsible
+for freeing the `unsigned char *` that is returned. `decode_sz` is an optional argument
+in case you need to know the size of the decoded data, otherwise you can just pass `NULL`.
+
+```c
+unsigned char *b64_decode(const char *s, size_t sz, size_t *decode_sz);
+```