From dd3fe7822b3f41b3ec7844618d044f8d05c09d02 Mon Sep 17 00:00:00 2001
From: Didactic Drunk <1479616+didactic-drunk@users.noreply.github.com>
Date: Sat, 14 Sep 2019 04:30:45 -0700
Subject: [PATCH] Add Chalsa CSPRNG benchmarks.

---
 README.md           |  6 +++++-
 benchmarks/rand.cr  | 36 ++++++++++++++++++++++++++++++++++++
 benchmarks/rand.txt |  7 +++++++
 3 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 benchmarks/rand.cr
 create mode 100644 benchmarks/rand.txt

diff --git a/README.md b/README.md
index f2b8f5b..713dddb 100644
--- a/README.md
+++ b/README.md
@@ -50,12 +50,15 @@ Crystal bindings for the [libsodium API](https://libsodium.gitbook.io/doc/)
     - [x] XChaCha20
     - [x] ChaCha20 Ietf
     - [x] ChaCha20
+    - [x] Easy to use methods available for use as a CSPRNG that are faster and safer than Crystal's.  See `benchmarks/rand.out`.
   - [ ] [One time auth](https://libsodium.gitbook.io/doc/advanced/poly1305)
   - [ ] Padding
 - Library features
   - [x] Faster builds by requiring what you need (`require "sodium/secret_box"`)
   - [x] Nonce reuse detection.
   - [x] All SecretKey's held in libsodium guarded memory.
+  - [x] No heap allocations after #initialize when possible.
+  - [x] Fast.  Benchmarks available in `benchmarks`.
   - [ ] Controlled memory wiping (by calling `.close`)
 
 ☑ Indicate specs are compared against test vectors from another source.
@@ -76,7 +79,8 @@ Several features in libsodium are already provided by Crystal:
 | [`Sodium::CryptoBox::SecretKey`](https://didactic-drunk.github.io/sodium.cr/Sodium/CryptoBox/PublicKey.html) .encrypt | I want anonymously send encrypted data. (No signatures) |
 | [`Sodium::Sign::SecretKey`](https://didactic-drunk.github.io/sodium.cr/Sodium/Sign/SecretKey.html) | I want to sign or verify messages. (No encryption) |
 | [`Sodium::SecretBox`](https://didactic-drunk.github.io/sodium.cr/Sodium/SecretBox.html) | I have a shared key and want to encrypt + authenticate data. |
-| [`Sodium::Cipher::SecretStream`](https://didactic-drunk.github.io/sodium.cr/Sodium/Cipher/SecretStream/XChaCha20Poly1305.html), AEAD | I have a shared key and want encrypt + authenticate streamed data. |
+| [`Sodium::Cipher::Aead::XChaCha20Poly1305Ietf`](https://didactic-drunk.github.io/sodium.cr/Sodium/Cipher/Aead/XChaCha20Poly1305Ietf.html) | I have a shared key and want to encrypt + authenticate data and authentication additional plaintext data. |
+| [`Sodium::Cipher::SecretStream`](https://didactic-drunk.github.io/sodium.cr/Sodium/Cipher/SecretStream/XChaCha20Poly1305.html) | I have a shared key and want encrypt + authenticate streamed data. |
 | [`Sodium::Digest::Blake2b`](https://didactic-drunk.github.io/sodium.cr/Sodium/Digest::Blake2b.html) | I want to hash data fast and securely. |
 | `Sodium::Digest::SipHash` | I want to hash data really fast and less securely. (Not implemented yet) |
 | [`Sodium::Pwhash`](https://didactic-drunk.github.io/sodium.cr/Sodium/Pwhash.html) | I want to hash a password and store it. |
diff --git a/benchmarks/rand.cr b/benchmarks/rand.cr
new file mode 100644
index 0000000..a9b6e26
--- /dev/null
+++ b/benchmarks/rand.cr
@@ -0,0 +1,36 @@
+require "benchmark"
+require "random/pcg32"
+require "random/isaac"
+require "../src/sodium/cipher/chalsa"
+
+pcgrand = Random::PCG32.new 0
+isaacrand = Random::ISAAC.new Bytes.new(32)
+
+ciphers = {{ Sodium::Cipher::Chalsa.subclasses }}.map do |klass|
+  cipher = klass.new.tap do |c|
+    c.key = Bytes.new c.key_size
+    c.nonce = Bytes.new c.nonce_size
+  end
+
+  # {short_name, cipher}
+  {klass.to_s.split("::").last, cipher}
+end.to_a
+# p ciphers
+
+buf = Bytes.new 1024
+
+Benchmark.ips warmup: 0.5 do |bm|
+  bm.report "PCG32" do
+    pcgrand.random_bytes buf
+  end
+
+  bm.report "ISAAC" do
+    isaacrand.random_bytes buf
+  end
+
+  ciphers.each do |name, cipher|
+    bm.report "#{name}" do
+      cipher.random_bytes buf
+    end
+  end
+end
diff --git a/benchmarks/rand.txt b/benchmarks/rand.txt
new file mode 100644
index 0000000..9b2eaa2
--- /dev/null
+++ b/benchmarks/rand.txt
@@ -0,0 +1,7 @@
+       PCG32 606.78k (  1.65µs) (± 1.07%)  0.0B/op   4.19× slower
+       ISAAC 373.63k (  2.68µs) (± 1.95%)  0.0B/op   6.80× slower
+    XSalsa20   1.84M (544.61ns) (± 1.17%)  0.0B/op   1.38× slower
+     Salsa20   2.37M (421.53ns) (± 1.24%)  0.0B/op   1.07× slower
+   XChaCha20   1.88M (530.86ns) (± 1.46%)  0.0B/op   1.35× slower
+ChaCha20Ietf   2.54M (393.65ns) (± 1.22%)  0.0B/op        fastest
+    ChaCha20   2.51M (398.58ns) (± 1.73%)  0.0B/op   1.01× slower