blake2b,blake2s: clarify difference between blake2b and blake2s

Fixes golang/go#37784

Change-Id: I2fdaf96979390f3744ba8135da78107a15f5e9a8
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/226845
Run-TryBot: Katie Hockman <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>
Reviewed-by: Filippo Valsorda <[email protected]>

Author: katiehockman

blake2b/blake2b.go

@@ -5,6 +5,8 @@
 // Package blake2b implements the BLAKE2b hash algorithm defined by RFC 7693
 // and the extendable output function (XOF) BLAKE2Xb.
 //
+// BLAKE2b is optimized for 64-bit platforms—including NEON-enabled ARMs—and
+// produces digests of any size between 1 and 64 bytes.
 // For a detailed specification of BLAKE2b see https://blake2.net/blake2.pdf
 // and for BLAKE2Xb see https://blake2.net/blake2x.pdf
 //

blake2s/blake2s.go

@@ -5,6 +5,8 @@
 // Package blake2s implements the BLAKE2s hash algorithm defined by RFC 7693
 // and the extendable output function (XOF) BLAKE2Xs.
 //
+// BLAKE2s is optimized for 8- to 32-bit platforms and produces digests of any
+// size between 1 and 32 bytes.
 // For a detailed specification of BLAKE2s see https://blake2.net/blake2.pdf
 // and for BLAKE2Xs see https://blake2.net/blake2x.pdf
 //