Switch to 4 double-rounds (i.e. to ChaCha8) by default.

Author: kernelmethod

src/keystream.jl

@@ -54,7 +54,7 @@ mutable struct ChaChaStream <: AbstractChaChaStream
         nonce,
         counter = UInt64(0),
         position = 1;
-        doublerounds = 10
+        doublerounds = 4
     )
         if doublerounds ≤ 0
             error("`doublerounds` must be an even positive number")
@@ -75,17 +75,24 @@ end
 """
     ChaCha20Stream(args...)
 
-Create a keystream for a ChaCha20 stream cipher.
+Create a random stream from the ChaCha20 stream cipher.
 """
 ChaCha20Stream(args...) = ChaChaStream(args...; doublerounds=10)
 
 """
     ChaCha12Stream(args...)
 
-Create a keystream for a ChaCha12 stream cipher.
+Create a random stream from the ChaCha12 stream cipher.
 """
 ChaCha12Stream(args...) = ChaChaStream(args...; doublerounds=6)
 
+"""
+    ChaCha8Stream(args...)
+
+Create a random stream from the ChaCha8 stream cipher.
+"""
+ChaCha8Stream(args...) = ChaChaStream(args...; doublerounds=4)
+
 function Base.show(io::IO, rng::ChaChaStream)
     msg = """
         ChaChaStream(

test/test_keystream.jl

@@ -12,10 +12,11 @@ using Test
         stream = ChaChaStream()
         @test stream.nonce == 0
         @test stream.position == 1
-
-        stream = ChaChaStream(; doublerounds=4)
         @test stream.doublerounds == 4
 
+        stream = ChaChaStream(; doublerounds=6)
+        @test stream.doublerounds == 6
+
         # We should receive an error if we try to create a
         # keystream with non-positive number of doublerounds
         @test_throws ErrorException ChaChaStream(; doublerounds=0)