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

kernelmethod · May 13, 2024 · be3380c · be3380c
1 parent 38fd5d9
commit be3380c
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Showing 2 changed files with 13 additions and 5 deletions.
diff --git a/src/keystream.jl b/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(

diff --git a/test/test_keystream.jl b/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)