diff --git a/argon2/argon2.go b/argon2/argon2.go index 2b65ec91ac..57ab8371cb 100644 --- a/argon2/argon2.go +++ b/argon2/argon2.go @@ -17,8 +17,8 @@ // It uses data-independent memory access, which is preferred for password // hashing and password-based key derivation. Argon2i requires more passes over // memory than Argon2id to protect from trade-off attacks. The recommended -// parameters (taken from [RFC 9106 Section 7.3]) for non-interactive operations are time=3 and to -// use the maximum available memory. +// parameters (taken from [RFC 9106 Section 7.3]) for non-interactive +// operations are time=3 and to use the maximum available memory. // // # Argon2id // @@ -26,11 +26,14 @@ // Argon2i and Argon2d. It uses data-independent memory access for the first // half of the first iteration over the memory and data-dependent memory access // for the rest. Argon2id is side-channel resistant and provides better brute- -// force cost savings due to time-memory tradeoffs than Argon2i. The recommended -// parameters for non-interactive operations (taken from [RFC 9106 Section 7.3]) are time=1 and to -// use the maximum available memory. +// force cost savings due to time-memory tradeoffs than Argon2i. [RFC 9106 +// Section 4] recommends time=1, memory=2*1024*1024 KiB (2 GiB), and threads=4 +// as the first recommended option. If much less memory is available, it +// recommends time=3, memory=64*1024 KiB (64 MiB), and threads=4 as the second +// recommended option. // // [argon2-specs.pdf]: https://github.com/P-H-C/phc-winner-argon2/blob/master/argon2-specs.pdf +// [RFC 9106 Section 4]: https://www.rfc-editor.org/rfc/rfc9106.html#section-4 // [RFC 9106 Section 7.3]: https://www.rfc-editor.org/rfc/rfc9106.html#section-7.3 package argon2 @@ -59,9 +62,9 @@ const ( // // key := argon2.Key([]byte("some password"), salt, 3, 32*1024, 4, 32) // -// [RFC 9106 Section 7.3] recommends time=3, and memory=32*1024 as a sensible number. -// If using that amount of memory (32 MB) is not possible in some contexts then -// the time parameter can be increased to compensate. +// The example above uses time=3 and memory=32*1024. Argon2i generally +// requires more passes over memory than Argon2id. If in doubt, prefer IDKey +// and its Argon2id parameter recommendations. // // The time parameter specifies the number of passes over the memory and the // memory parameter specifies the size of the memory in KiB. For example @@ -69,8 +72,6 @@ const ( // adjusted to the number of available CPUs. The cost parameters should be // increased as memory latency and CPU parallelism increases. Remember to get a // good random salt. -// -// [RFC 9106 Section 7.3]: https://www.rfc-editor.org/rfc/rfc9106.html#section-7.3 func Key(password, salt []byte, time, memory uint32, threads uint8, keyLen uint32) []byte { return deriveKey(argon2i, password, salt, nil, nil, time, memory, threads, keyLen) } @@ -83,20 +84,20 @@ func Key(password, salt []byte, time, memory uint32, threads uint8, keyLen uint3 // For example, you can get a derived key for e.g. AES-256 (which needs a // 32-byte key) by doing: // -// key := argon2.IDKey([]byte("some password"), salt, 1, 64*1024, 4, 32) +// key := argon2.IDKey([]byte("some password"), salt, 1, 2*1024*1024, 4, 32) // -// [RFC 9106 Section 7.3] recommends time=1, and memory=64*1024 as a sensible number. -// If using that amount of memory (64 MB) is not possible in some contexts then -// the time parameter can be increased to compensate. +// The example above uses the first [RFC 9106 Section 4] recommended option. +// If much less memory is available, the second recommended option is time=3, +// memory=64*1024 KiB (64 MiB), and threads=4. // // The time parameter specifies the number of passes over the memory and the // memory parameter specifies the size of the memory in KiB. For example -// memory=64*1024 sets the memory cost to ~64 MB. The number of threads can be -// adjusted to the numbers of available CPUs. The cost parameters should be +// memory=2*1024*1024 sets the memory cost to ~2 GiB. The number of threads can +// be adjusted to the numbers of available CPUs. The cost parameters should be // increased as memory latency and CPU parallelism increases. Remember to get a // good random salt. // -// [RFC 9106 Section 7.3]: https://www.rfc-editor.org/rfc/rfc9106.html#section-7.3 +// [RFC 9106 Section 4]: https://www.rfc-editor.org/rfc/rfc9106.html#section-4 func IDKey(password, salt []byte, time, memory uint32, threads uint8, keyLen uint32) []byte { return deriveKey(argon2id, password, salt, nil, nil, time, memory, threads, keyLen) }