xts: clarify Cipher concurrency guarantee

lukechampine · lukechampine · commit 14d81f589f3a · 2018-06-14T11:17:51.000-04:00
diff --git a/xts/xts.go b/xts/xts.go
@@ -30,8 +30,8 @@ import (
 	"golang.org/x/crypto/internal/subtle"
 )
 
-// Cipher contains an expanded key structure. It doesn't contain mutable state
-// and therefore can be used concurrently.
+// Cipher contains an expanded key structure. It is safe for concurrent use if
+// the underlying block cipher is safe for concurrent use.
 type Cipher struct {
 	k1, k2 cipher.Block
 }

Original file line number	Diff line number	Diff line change
`@@ -30,8 +30,8 @@ import (`
`30`	`30`	`"golang.org/x/crypto/internal/subtle"`
`31`	`31`	`)`
`32`	`32`
`33`		`-// Cipher contains an expanded key structure. It doesn't contain mutable state`
`34`		`-// and therefore can be used concurrently.`
	`33`	`+// Cipher contains an expanded key structure. It is safe for concurrent use if`
	`34`	`+// the underlying block cipher is safe for concurrent use.`
`35`	`35`	`type Cipher struct {`
`36`	`36`	`k1, k2 cipher.Block`
`37`	`37`	`}`