Package hmac
Package hmac implements the Keyed-Hash Message Authentication Code (HMAC) as
defined in U.S. Federal Information Processing Standards Publication 198.
An HMAC is a cryptographic hash that uses a key to sign a message.
The receiver verifies the hash by recomputing it using the same key.
Receivers should be careful to use Equal to compare MACs in order to avoid
timing side-channels:
// ValidMAC reports whether messageMAC is a valid HMAC tag for message.
func ValidMAC(message, messageMAC, key []byte) bool {
mac := hmac.New(sha256.New, key)
mac.Write(message)
expectedMAC := mac.Sum(nil)
return hmac.Equal(messageMAC, expectedMAC)
}
In the call graph viewer below, each node
is a function belonging to this package
and its children are the functions it
calls—perhaps dynamically.
The root nodes are the entry points of the
package: functions that may be called from
outside the package.
There may be non-exported or anonymous
functions among them if they are called
dynamically from another package.
Click a node to visit that function's source code.
From there you can visit its callers by
clicking its declaring func
token.
Functions may be omitted if they were
determined to be unreachable in the
particular programs or tests that were
analyzed.
func Equal(mac1, mac2 []byte) bool
Equal compares two MACs for equality without leaking timing information.
func New(h func() hash.Hash, key []byte) hash.Hash
New returns a new HMAC hash using the given hash.Hash type and key.
Note that unlike other hash implementations in the standard library,
the returned Hash does not implement encoding.BinaryMarshaler
or encoding.BinaryUnmarshaler.