58 lines
1.3 KiB
Go
58 lines
1.3 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build !gccgo,!purego
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package poly1305
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//go:noescape
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func update(state *macState, msg []byte)
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func sum(out *[16]byte, m []byte, key *[32]byte) {
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h := newMAC(key)
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h.Write(m)
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h.Sum(out)
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}
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func newMAC(key *[32]byte) (h mac) {
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initialize(key, &h.r, &h.s)
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return
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}
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// mac is a wrapper for macGeneric that redirects calls that would have gone to
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// updateGeneric to update.
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//
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// Its Write and Sum methods are otherwise identical to the macGeneric ones, but
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// using function pointers would carry a major performance cost.
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type mac struct{ macGeneric }
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func (h *mac) Write(p []byte) (int, error) {
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nn := len(p)
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if h.offset > 0 {
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n := copy(h.buffer[h.offset:], p)
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if h.offset+n < TagSize {
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h.offset += n
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return nn, nil
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}
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p = p[n:]
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h.offset = 0
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update(&h.macState, h.buffer[:])
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}
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if n := len(p) - (len(p) % TagSize); n > 0 {
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update(&h.macState, p[:n])
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p = p[n:]
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}
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if len(p) > 0 {
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h.offset += copy(h.buffer[h.offset:], p)
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}
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return nn, nil
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}
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func (h *mac) Sum(out *[16]byte) {
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state := h.macState
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if h.offset > 0 {
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update(&state, h.buffer[:h.offset])
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}
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finalize(out, &state.h, &state.s)
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}
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