ca4971cbae
We no longer need to fork them. This is in preparation for pulling it via Go modules, but probably need to figure out the network issue first. Slightly bad manners for CI to do that. Change-Id: Ic258264f3c3559817d5e4921e4ad3282e94d05fe Reviewed-on: https://boringssl-review.googlesource.com/31904 Commit-Queue: David Benjamin <davidben@google.com> CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> Reviewed-by: Adam Langley <agl@google.com>
34 lines
1.3 KiB
Go
34 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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/*
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Package poly1305 implements Poly1305 one-time message authentication code as
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specified in https://cr.yp.to/mac/poly1305-20050329.pdf.
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Poly1305 is a fast, one-time authentication function. It is infeasible for an
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attacker to generate an authenticator for a message without the key. However, a
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key must only be used for a single message. Authenticating two different
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messages with the same key allows an attacker to forge authenticators for other
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messages with the same key.
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Poly1305 was originally coupled with AES in order to make Poly1305-AES. AES was
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used with a fixed key in order to generate one-time keys from an nonce.
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However, in this package AES isn't used and the one-time key is specified
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directly.
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*/
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package poly1305 // import "golang.org/x/crypto/poly1305"
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import "crypto/subtle"
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// TagSize is the size, in bytes, of a poly1305 authenticator.
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const TagSize = 16
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// Verify returns true if mac is a valid authenticator for m with the given
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// key.
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func Verify(mac *[16]byte, m []byte, key *[32]byte) bool {
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var tmp [16]byte
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Sum(&tmp, m, key)
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return subtle.ConstantTimeCompare(tmp[:], mac[:]) == 1
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}
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