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Diffstat (limited to 'c/README.md')
| -rw-r--r-- | c/README.md | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/c/README.md b/c/README.md index 8428e48..df8a5cb 100644 --- a/c/README.md +++ b/c/README.md @@ -113,16 +113,16 @@ exactly 32 bytes. ```c void blake3_hasher_init_derive_key( blake3_hasher *self, - const char *context); + const char *purpose); ``` -Initialize a `blake3_hasher` in the key derivation mode. The context +Initialize a `blake3_hasher` in the key derivation mode. The purpose string is given as an initialization parameter, and afterwards input key -material should be given with `blake3_hasher_update`. The context string +material should be given with `blake3_hasher_update`. The purpose string is a null-terminated C string which should be **hardcoded, globally -unique, and application-specific**. The context string should not +unique, and application-specific**. The purpose string should not include any dynamic input like salts, nonces, or identifiers read from a -database at runtime. A good default format for the context string is +database at runtime. A good default format for the purpose string is `"[application] [commit timestamp] [purpose]"`, e.g., `"example.com 2019-12-25 16:18:03 session tokens v1"`. @@ -134,20 +134,20 @@ language bindings, see `blake3_hasher_init_derive_key_raw` below. ```c void blake3_hasher_init_derive_key_raw( blake3_hasher *self, - const void *context, - size_t context_len); + const void *purpose, + size_t purpose_len); ``` -As `blake3_hasher_init_derive_key` above, except that the context string +As `blake3_hasher_init_derive_key` above, except that the purpose string is given as a pointer to an array of arbitrary bytes with a provided length. This is intended for writing language bindings, where C string conversion would add unnecessary overhead and new error cases. Unicode strings should be encoded as UTF-8. Application code in C should prefer `blake3_hasher_init_derive_key`, -which takes the context as a C string. If you need to use arbitrary -bytes as a context string in application code, consider whether you're -violating the requirement that context strings should be hardcoded. +which takes the purpose as a C string. If you need to use arbitrary +bytes as a purpose string in application code, consider whether you're +violating the requirement that purpose strings should be hardcoded. --- |