doc: correct crypto encoding information

The default encoding for crypto methods was changed in v6.0.0,
with v4.x keeping a default of `binary`.

Ref: nodejs#5500
Fixes: nodejs#7712

doc/api/crypto.md

@@ -674,7 +674,7 @@ called. Multiple calls to `hmac.digest()` will result in an error being thrown.
 Updates the `Hmac` content with the given `data`, the encoding of which
 is given in `input_encoding` and can be `'utf8'`, `'ascii'` or
 `'binary'`. If `encoding` is not provided, and the `data` is a string, an
-encoding of `'utf8'` is enforced. If `data` is a [`Buffer`][] then
+encoding of `'binary'` is enforced. If `data` is a [`Buffer`][] then
 `input_encoding` is ignored.
 
 This can be called many times with new data as it is streamed.
@@ -765,7 +765,7 @@ called. Multiple calls to `sign.sign()` will result in an error being thrown.
 Updates the `Sign` content with the given `data`, the encoding of which
 is given in `input_encoding` and can be `'utf8'`, `'ascii'` or
 `'binary'`. If `encoding` is not provided, and the `data` is a string, an
-encoding of `'utf8'` is enforced. If `data` is a [`Buffer`][] then
+encoding of `'binary'` is enforced. If `data` is a [`Buffer`][] then
 `input_encoding` is ignored.
 
 This can be called many times with new data as it is streamed.
@@ -817,7 +817,7 @@ console.log(verify.verify(public_key, signature));
 Updates the `Verify` content with the given `data`, the encoding of which
 is given in `input_encoding` and can be `'utf8'`, `'ascii'` or
 `'binary'`. If `encoding` is not provided, and the `data` is a string, an
-encoding of `'utf8'` is enforced. If `data` is a [`Buffer`][] then
+encoding of `'binary'` is enforced. If `data` is a [`Buffer`][] then
 `input_encoding` is ignored.
 
 This can be called many times with new data as it is streamed.
@@ -848,7 +848,7 @@ or [buffers][`Buffer`]. The default value is `'buffer'`, which makes methods
 default to [`Buffer`][] objects.
 
 The `crypto.DEFAULT_ENCODING` mechanism is provided for backwards compatibility
-with legacy programs that expect `'binary'` to be the default encoding.
+with legacy programs that expect `'utf8'` to be the default encoding.
 
 New applications should expect the default to be `'buffer'`. This property may
 become deprecated in a future Node.js release.