ChaChaPoly authenticated cipher

doc/crypto.dox

@@ -29,6 +29,7 @@
 \li Block ciphers: AES128, AES192, AES256
 \li Block cipher modes: CTR, CFB, CBC, OFB
 \li Stream ciphers: ChaCha
+\li Authenticated encryption with associated data (AEAD): ChaChaPoly
 \li Hash algorithms: SHA1, SHA256, SHA512, SHA3_256, SHA3_512, BLAKE2s, BLAKE2b (regular and HMAC modes)
 \li Message authenticators: Poly1305
 \li Public key algorithms: Curve25519
@@ -68,6 +69,7 @@ Ardunino Mega 2560 running at 16 MHz are similar:
 <tr><td>ChaCha (20 rounds)</td><td align="right">14.87us</td><td align="right">14.88us</td><td align="right">43.74us</td><td align="right">132</td></tr>
 <tr><td>ChaCha (12 rounds)</td><td align="right">10.38us</td><td align="right">10.38us</td><td align="right">43.74us</td><td align="right">132</td></tr>
 <tr><td>ChaCha (8 rounds)</td><td align="right">8.13us</td><td align="right">8.14us</td><td align="right">43.74us</td><td align="right">132</td></tr>
+<tr><td>ChaChaPoly</td><td align="right">41.23us</td><td align="right">41.23us</td><td align="right">902.55us</td><td align="right">255</td></tr>
 <tr><td>SHA1</td><td align="right">21.90us</td><td> </td><td align="right"> </td><td align="right">95</td></tr>
 <tr><td>SHA256</td><td align="right">43.85us</td><td> </td><td align="right"> </td><td align="right">107</td></tr>
 <tr><td>SHA512</td><td align="right">123.24us</td><td> </td><td align="right"> </td><td align="right">211</td></tr>

doc/mainpage.dox

@@ -94,6 +94,7 @@ realtime clock and the LCD library to implement an alarm clock.
 \li Block ciphers: AES128, AES192, AES256
 \li Block cipher modes: CTR, CFB, CBC, OFB
 \li Stream ciphers: ChaCha
+\li Authenticated encryption with associated data (AEAD): ChaChaPoly
 \li Hash algorithms: SHA1, SHA256, SHA512, SHA3_256, SHA3_512, BLAKE2s, BLAKE2b (regular and HMAC modes)
 \li Message authenticators: Poly1305
 \li Public key algorithms: Curve25519

libraries/Crypto/AuthenticatedCipher.cpp

@@ -79,6 +79,7 @@ AuthenticatedCipher::~AuthenticatedCipher()
  * \brief Adds extra data that will be authenticated but not encrypted.
  *
  * \param data The extra data to be authenticated.
+ * \param len The number of bytes of extra data to be authenticated.
  *
  * This function must be called before the first call to encrypt() or
  * decrypt().  That is, it is assumed that all extra data for authentication
@@ -93,7 +94,7 @@ AuthenticatedCipher::~AuthenticatedCipher()
  */
 
 /**
- * \fn void AuthenticatedCipher::AuthenticatedCipher::computeTag(void *tag, size_t len)
+ * \fn void AuthenticatedCipher::computeTag(void *tag, size_t len)
  * \brief Finalizes the encryption process and computes the authentication tag.
  *
  * \param tag Points to the buffer to write the tag to.
@@ -104,7 +105,7 @@ AuthenticatedCipher::~AuthenticatedCipher()
  */
 
 /**
- * \fn bool AuthenticatedCipher::AuthenticatedCipher::checkTag(const void *tag, size_t len)
+ * \fn bool AuthenticatedCipher::checkTag(const void *tag, size_t len)
  * \brief Finalizes the decryption process and checks the authentication tag.
  *
  * \param tag The tag value from the incoming ciphertext to be checked.

libraries/Crypto/ChaCha.cpp

@@ -110,7 +110,7 @@ bool ChaCha::setKey(const uint8_t *key, size_t len)
 
 bool ChaCha::setIV(const uint8_t *iv, size_t len)
 {
-    // From draft-nir-cfrg-chacha20-poly1305-04.txt, we can use either
+    // From draft-nir-cfrg-chacha20-poly1305-10.txt, we can use either
     // 64-bit or 96-bit nonces.  The 96-bit nonce consists of the high
     // word of the counter prepended to a regular 64-bit nonce for ChaCha.
     if (len == 8) {
@@ -192,6 +192,29 @@ void ChaCha::decrypt(uint8_t *output, const uint8_t *input, size_t len)
     encrypt(output, input, len);
 }
 
+/**
+ * \brief Generates a single block of output direct from the keystream.
+ *
+ * \param output The output buffer to fill with keystream bytes.
+ *
+ * Unlike encrypt(), this function does not XOR the keystream with
+ * plaintext data.  Instead it generates the keystream directly into
+ * the caller-supplied buffer.  This is useful if the caller knows
+ * that the plaintext is all-zeroes.
+ *
+ * \sa encrypt()
+ */
+void ChaCha::keystreamBlock(uint32_t *output)
+{
+    // Generate the hash output directly into the caller-supplied buffer.
+    hashCore(output, (const uint32_t *)block, rounds);
+    posn = 64;
+
+    // Increment the lowest counter byte.  We are assuming that the caller
+    // is ChaChaPoly::setKey() and that the previous counter value was zero.
+    block[48] = 1;
+}
+
 void ChaCha::clear()
 {
     clean(block);

libraries/Crypto/ChaCha.h

@@ -25,6 +25,8 @@
 
 #include "Cipher.h"
 
+class ChaChaPoly;
+
 class ChaCha : public Cipher
 {
 public:
@@ -53,6 +55,10 @@ private:
     uint8_t stream[64];
     uint8_t rounds;
     uint8_t posn;
+
+    void keystreamBlock(uint32_t *output);
+
+    friend class ChaChaPoly;
 };
 
 #endif

libraries/Crypto/ChaChaPoly.cpp

@@ -0,0 +1,169 @@
+/*
+ * Copyright (C) 2015 Southern Storm Software, Pty Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include "ChaChaPoly.h"
+#include "Crypto.h"
+#include "utility/EndianUtil.h"
+#include <string.h>
+
+/**
+ * \class ChaChaPoly ChaChaPoly.h <ChaChaPoly.h>
+ * \brief Authenticated cipher based on ChaCha and Poly1305
+ *
+ * ChaChaPoly is an authenticated cipher based on a combination of
+ * ChaCha with 20 rounds for encryption and Poly1305 for authentication.
+ * The resulting cipher has a 256-bit key, a 64-bit or 96-bit
+ * initialization vector, and a 128-bit authentication tag.
+ *
+ * Reference: https://tools.ietf.org/html/draft-irtf-cfrg-chacha20-poly1305-10
+ *
+ * \sa ChaCha, Poly1305, AuthenticatedCipher
+ */
+
+/**
+ * \brief Constructs a new ChaChaPoly authenticated cipher.
+ */
+ChaChaPoly::ChaChaPoly()
+{
+    state.authSize = 0;
+    state.dataSize = 0;
+    state.dataStarted = false;
+    state.ivSize = 8;
+}
+
+/**
+ * \brief Destroys this ChaChaPoly authenticated cipher.
+ */
+ChaChaPoly::~ChaChaPoly()
+{
+    clean(state);
+}
+
+size_t ChaChaPoly::keySize() const
+{
+    // Default key size is 256-bit, but any key size is allowed.
+    return 32;
+}
+
+size_t ChaChaPoly::ivSize() const
+{
+    // Return 8 but we also support 12-byte nonces in setIV().
+    return 8;
+}
+
+size_t ChaChaPoly::tagSize() const
+{
+    // Any tag size between 1 and 16 is supported.
+    return 16;
+}
+
+bool ChaChaPoly::setKey(const uint8_t *key, size_t len)
+{
+    return chacha.setKey(key, len);
+}
+
+bool ChaChaPoly::setIV(const uint8_t *iv, size_t len)
+{
+    // ChaCha::setIV() supports both 64-bit and 96-bit nonces.
+    if (!chacha.setIV(iv, len))
+        return false;
+
+    // Generate the key and nonce to use for Poly1305.
+    uint32_t data[16];
+    chacha.keystreamBlock(data);
+    poly1305.reset(data);
+    memcpy(state.nonce, data + 4, 16);
+    clean(data);
+
+    // Reset the size counters for the auth data and payload.
+    state.authSize = 0;
+    state.dataSize = 0;
+    state.dataStarted = false;
+    state.ivSize = len;
+}
+
+void ChaChaPoly::encrypt(uint8_t *output, const uint8_t *input, size_t len)
+{
+    if (!state.dataStarted) {
+        poly1305.pad();
+        state.dataStarted = true;
+    }
+    chacha.encrypt(output, input, len);
+    poly1305.update(output, len);
+    state.dataSize += len;
+}
+
+void ChaChaPoly::decrypt(uint8_t *output, const uint8_t *input, size_t len)
+{
+    if (!state.dataStarted) {
+        poly1305.pad();
+        state.dataStarted = true;
+    }
+    poly1305.update(input, len);
+    chacha.encrypt(output, input, len); // encrypt() is the same as decrypt()
+    state.dataSize += len;
+}
+
+void ChaChaPoly::addAuthData(const void *data, size_t len)
+{
+    if (!state.dataStarted) {
+        poly1305.update(data, len);
+        state.authSize += len;
+    }
+}
+
+void ChaChaPoly::computeTag(void *tag, size_t len)
+{
+    uint64_t sizes[2];
+
+    // Pad the final Poly1305 block and then hash the sizes.
+    poly1305.pad();
+    sizes[0] = htole64(state.authSize);
+    sizes[1] = htole64(state.dataSize);
+    poly1305.update(sizes, sizeof(sizes));
+
+    // Compute the tag and copy it to the return buffer.
+    poly1305.finalize(state.nonce, tag, len);
+    clean(sizes);
+}
+
+bool ChaChaPoly::checkTag(const void *tag, size_t len)
+{
+    // Can never match if the expected tag length is too long.
+    if (len > 16)
+        return false;
+
+    // Compute the tag and check it.
+    uint8_t temp[16];
+    computeTag(temp, len);
+    bool equal = secure_compare(temp, tag, len);
+    clean(temp);
+    return equal;
+}
+
+void ChaChaPoly::clear()
+{
+    chacha.clear();
+    poly1305.clear();
+    clean(state);
+    state.ivSize = 8;
+}

libraries/Crypto/ChaChaPoly.h

@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2015 Southern Storm Software, Pty Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef CRYPTO_CHACHAPOLY_H
+#define CRYPTO_CHACHAPOLY_H
+
+#include "AuthenticatedCipher.h"
+#include "ChaCha.h"
+#include "Poly1305.h"
+
+class ChaChaPoly : public AuthenticatedCipher
+{
+public:
+    ChaChaPoly();
+    virtual ~ChaChaPoly();
+
+    size_t keySize() const;
+    size_t ivSize() const;
+    size_t tagSize() const;
+
+    bool setKey(const uint8_t *key, size_t len);
+    bool setIV(const uint8_t *iv, size_t len);
+
+    void encrypt(uint8_t *output, const uint8_t *input, size_t len);
+    void decrypt(uint8_t *output, const uint8_t *input, size_t len);
+
+    void addAuthData(const void *data, size_t len);
+
+    void computeTag(void *tag, size_t len);
+    bool checkTag(const void *tag, size_t len);
+
+    void clear();
+
+private:
+    ChaCha chacha;
+    Poly1305 poly1305;
+    struct {
+        uint8_t nonce[16];
+        uint64_t authSize;
+        uint64_t dataSize;
+        bool dataStarted;
+        uint8_t ivSize;
+    } state;
+};
+
+#endif

libraries/Crypto/Poly1305.cpp

@@ -252,6 +252,7 @@ void Poly1305::pad()
 {
     if (state.chunkSize != 0) {
         memset(((uint8_t *)state.c) + state.chunkSize, 0, 16 - state.chunkSize);
+        littleToHost(state.c, NUM_LIMBS_128BIT);
         state.c[NUM_LIMBS_128BIT] = 1;
         processChunk();
         state.chunkSize = 0;

libraries/Crypto/examples/TestChaChaPoly/TestChaChaPoly.ino

@@ -0,0 +1,448 @@
+/*
+ * Copyright (C) 2015 Southern Storm Software, Pty Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+/*
+This example runs tests on the ChaChaPoly implementation to verify
+correct behaviour.
+*/
+
+#include <Crypto.h>
+#include <ChaChaPoly.h>
+#include <string.h>
+#include <avr/pgmspace.h>
+
+#define MAX_PLAINTEXT_LEN 265
+
+struct TestVector
+{
+    const char *name;
+    uint8_t key[32];
+    uint8_t plaintext[MAX_PLAINTEXT_LEN];
+    uint8_t ciphertext[MAX_PLAINTEXT_LEN];
+    uint8_t authdata[16];
+    uint8_t iv[16];
+    uint8_t tag[16];
+    size_t authsize;
+    size_t datasize;
+    size_t tagsize;
+    size_t ivsize;
+};
+
+// Test vectors for ChaChaPoly from draft-nir-cfrg-chacha20-poly1305-04.txt
+static TestVector const testVectorChaChaPoly_1 PROGMEM = {
+    .name        = "ChaChaPoly #1",
+    .key         = {0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
+                    0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
+                    0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
+                    0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f},
+    .plaintext   = {0x4c, 0x61, 0x64, 0x69, 0x65, 0x73, 0x20, 0x61,
+                    0x6e, 0x64, 0x20, 0x47, 0x65, 0x6e, 0x74, 0x6c,
+                    0x65, 0x6d, 0x65, 0x6e, 0x20, 0x6f, 0x66, 0x20,
+                    0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x61, 0x73,
+                    0x73, 0x20, 0x6f, 0x66, 0x20, 0x27, 0x39, 0x39,
+                    0x3a, 0x20, 0x49, 0x66, 0x20, 0x49, 0x20, 0x63,
+                    0x6f, 0x75, 0x6c, 0x64, 0x20, 0x6f, 0x66, 0x66,
+                    0x65, 0x72, 0x20, 0x79, 0x6f, 0x75, 0x20, 0x6f,
+                    0x6e, 0x6c, 0x79, 0x20, 0x6f, 0x6e, 0x65, 0x20,
+                    0x74, 0x69, 0x70, 0x20, 0x66, 0x6f, 0x72, 0x20,
+                    0x74, 0x68, 0x65, 0x20, 0x66, 0x75, 0x74, 0x75,
+                    0x72, 0x65, 0x2c, 0x20, 0x73, 0x75, 0x6e, 0x73,
+                    0x63, 0x72, 0x65, 0x65, 0x6e, 0x20, 0x77, 0x6f,
+                    0x75, 0x6c, 0x64, 0x20, 0x62, 0x65, 0x20, 0x69,
+                    0x74, 0x2e},
+    .ciphertext  = {0xd3, 0x1a, 0x8d, 0x34, 0x64, 0x8e, 0x60, 0xdb,
+                    0x7b, 0x86, 0xaf, 0xbc, 0x53, 0xef, 0x7e, 0xc2,
+                    0xa4, 0xad, 0xed, 0x51, 0x29, 0x6e, 0x08, 0xfe,
+                    0xa9, 0xe2, 0xb5, 0xa7, 0x36, 0xee, 0x62, 0xd6,
+                    0x3d, 0xbe, 0xa4, 0x5e, 0x8c, 0xa9, 0x67, 0x12,
+                    0x82, 0xfa, 0xfb, 0x69, 0xda, 0x92, 0x72, 0x8b,
+                    0x1a, 0x71, 0xde, 0x0a, 0x9e, 0x06, 0x0b, 0x29,
+                    0x05, 0xd6, 0xa5, 0xb6, 0x7e, 0xcd, 0x3b, 0x36,
+                    0x92, 0xdd, 0xbd, 0x7f, 0x2d, 0x77, 0x8b, 0x8c,
+                    0x98, 0x03, 0xae, 0xe3, 0x28, 0x09, 0x1b, 0x58,
+                    0xfa, 0xb3, 0x24, 0xe4, 0xfa, 0xd6, 0x75, 0x94,
+                    0x55, 0x85, 0x80, 0x8b, 0x48, 0x31, 0xd7, 0xbc,
+                    0x3f, 0xf4, 0xde, 0xf0, 0x8e, 0x4b, 0x7a, 0x9d,
+                    0xe5, 0x76, 0xd2, 0x65, 0x86, 0xce, 0xc6, 0x4b,
+                    0x61, 0x16},
+    .authdata    = {0x50, 0x51, 0x52, 0x53, 0xc0, 0xc1, 0xc2, 0xc3,
+                    0xc4, 0xc5, 0xc6, 0xc7},
+    .iv          = {0x07, 0x00, 0x00, 0x00, 0x40, 0x41, 0x42, 0x43,
+                    0x44, 0x45, 0x46, 0x47},
+    .tag         = {0x1a, 0xe1, 0x0b, 0x59, 0x4f, 0x09, 0xe2, 0x6a,
+                    0x7e, 0x90, 0x2e, 0xcb, 0xd0, 0x60, 0x06, 0x91},
+    .authsize    = 12,
+    .datasize    = 114,
+    .tagsize     = 16,
+    .ivsize      = 12
+};
+static TestVector const testVectorChaChaPoly_2 PROGMEM = {
+    .name        = "ChaChaPoly #2",
+    .key         = {0x1c, 0x92, 0x40, 0xa5, 0xeb, 0x55, 0xd3, 0x8a,
+                    0xf3, 0x33, 0x88, 0x86, 0x04, 0xf6, 0xb5, 0xf0,
+                    0x47, 0x39, 0x17, 0xc1, 0x40, 0x2b, 0x80, 0x09,
+                    0x9d, 0xca, 0x5c, 0xbc, 0x20, 0x70, 0x75, 0xc0},
+    .plaintext   = {0x49, 0x6e, 0x74, 0x65, 0x72, 0x6e, 0x65, 0x74,
+                    0x2d, 0x44, 0x72, 0x61, 0x66, 0x74, 0x73, 0x20,
+                    0x61, 0x72, 0x65, 0x20, 0x64, 0x72, 0x61, 0x66,
+                    0x74, 0x20, 0x64, 0x6f, 0x63, 0x75, 0x6d, 0x65,
+                    0x6e, 0x74, 0x73, 0x20, 0x76, 0x61, 0x6c, 0x69,
+                    0x64, 0x20, 0x66, 0x6f, 0x72, 0x20, 0x61, 0x20,
+                    0x6d, 0x61, 0x78, 0x69, 0x6d, 0x75, 0x6d, 0x20,
+                    0x6f, 0x66, 0x20, 0x73, 0x69, 0x78, 0x20, 0x6d,
+                    0x6f, 0x6e, 0x74, 0x68, 0x73, 0x20, 0x61, 0x6e,
+                    0x64, 0x20, 0x6d, 0x61, 0x79, 0x20, 0x62, 0x65,
+                    0x20, 0x75, 0x70, 0x64, 0x61, 0x74, 0x65, 0x64,
+                    0x2c, 0x20, 0x72, 0x65, 0x70, 0x6c, 0x61, 0x63,
+                    0x65, 0x64, 0x2c, 0x20, 0x6f, 0x72, 0x20, 0x6f,
+                    0x62, 0x73, 0x6f, 0x6c, 0x65, 0x74, 0x65, 0x64,
+                    0x20, 0x62, 0x79, 0x20, 0x6f, 0x74, 0x68, 0x65,
+                    0x72, 0x20, 0x64, 0x6f, 0x63, 0x75, 0x6d, 0x65,
+                    0x6e, 0x74, 0x73, 0x20, 0x61, 0x74, 0x20, 0x61,
+                    0x6e, 0x79, 0x20, 0x74, 0x69, 0x6d, 0x65, 0x2e,
+                    0x20, 0x49, 0x74, 0x20, 0x69, 0x73, 0x20, 0x69,
+                    0x6e, 0x61, 0x70, 0x70, 0x72, 0x6f, 0x70, 0x72,
+                    0x69, 0x61, 0x74, 0x65, 0x20, 0x74, 0x6f, 0x20,
+                    0x75, 0x73, 0x65, 0x20, 0x49, 0x6e, 0x74, 0x65,
+                    0x72, 0x6e, 0x65, 0x74, 0x2d, 0x44, 0x72, 0x61,
+                    0x66, 0x74, 0x73, 0x20, 0x61, 0x73, 0x20, 0x72,
+                    0x65, 0x66, 0x65, 0x72, 0x65, 0x6e, 0x63, 0x65,
+                    0x20, 0x6d, 0x61, 0x74, 0x65, 0x72, 0x69, 0x61,
+                    0x6c, 0x20, 0x6f, 0x72, 0x20, 0x74, 0x6f, 0x20,
+                    0x63, 0x69, 0x74, 0x65, 0x20, 0x74, 0x68, 0x65,
+                    0x6d, 0x20, 0x6f, 0x74, 0x68, 0x65, 0x72, 0x20,
+                    0x74, 0x68, 0x61, 0x6e, 0x20, 0x61, 0x73, 0x20,
+                    0x2f, 0xe2, 0x80, 0x9c, 0x77, 0x6f, 0x72, 0x6b,
+                    0x20, 0x69, 0x6e, 0x20, 0x70, 0x72, 0x6f, 0x67,
+                    0x72, 0x65, 0x73, 0x73, 0x2e, 0x2f, 0xe2, 0x80,
+                    0x9d},
+    .ciphertext  = {0x64, 0xa0, 0x86, 0x15, 0x75, 0x86, 0x1a, 0xf4,
+                    0x60, 0xf0, 0x62, 0xc7, 0x9b, 0xe6, 0x43, 0xbd,
+                    0x5e, 0x80, 0x5c, 0xfd, 0x34, 0x5c, 0xf3, 0x89,
+                    0xf1, 0x08, 0x67, 0x0a, 0xc7, 0x6c, 0x8c, 0xb2,
+                    0x4c, 0x6c, 0xfc, 0x18, 0x75, 0x5d, 0x43, 0xee,
+                    0xa0, 0x9e, 0xe9, 0x4e, 0x38, 0x2d, 0x26, 0xb0,
+                    0xbd, 0xb7, 0xb7, 0x3c, 0x32, 0x1b, 0x01, 0x00,
+                    0xd4, 0xf0, 0x3b, 0x7f, 0x35, 0x58, 0x94, 0xcf,
+                    0x33, 0x2f, 0x83, 0x0e, 0x71, 0x0b, 0x97, 0xce,
+                    0x98, 0xc8, 0xa8, 0x4a, 0xbd, 0x0b, 0x94, 0x81,
+                    0x14, 0xad, 0x17, 0x6e, 0x00, 0x8d, 0x33, 0xbd,
+                    0x60, 0xf9, 0x82, 0xb1, 0xff, 0x37, 0xc8, 0x55,
+                    0x97, 0x97, 0xa0, 0x6e, 0xf4, 0xf0, 0xef, 0x61,
+                    0xc1, 0x86, 0x32, 0x4e, 0x2b, 0x35, 0x06, 0x38,
+                    0x36, 0x06, 0x90, 0x7b, 0x6a, 0x7c, 0x02, 0xb0,
+                    0xf9, 0xf6, 0x15, 0x7b, 0x53, 0xc8, 0x67, 0xe4,
+                    0xb9, 0x16, 0x6c, 0x76, 0x7b, 0x80, 0x4d, 0x46,
+                    0xa5, 0x9b, 0x52, 0x16, 0xcd, 0xe7, 0xa4, 0xe9,
+                    0x90, 0x40, 0xc5, 0xa4, 0x04, 0x33, 0x22, 0x5e,
+                    0xe2, 0x82, 0xa1, 0xb0, 0xa0, 0x6c, 0x52, 0x3e,
+                    0xaf, 0x45, 0x34, 0xd7, 0xf8, 0x3f, 0xa1, 0x15,
+                    0x5b, 0x00, 0x47, 0x71, 0x8c, 0xbc, 0x54, 0x6a,
+                    0x0d, 0x07, 0x2b, 0x04, 0xb3, 0x56, 0x4e, 0xea,
+                    0x1b, 0x42, 0x22, 0x73, 0xf5, 0x48, 0x27, 0x1a,
+                    0x0b, 0xb2, 0x31, 0x60, 0x53, 0xfa, 0x76, 0x99,
+                    0x19, 0x55, 0xeb, 0xd6, 0x31, 0x59, 0x43, 0x4e,
+                    0xce, 0xbb, 0x4e, 0x46, 0x6d, 0xae, 0x5a, 0x10,
+                    0x73, 0xa6, 0x72, 0x76, 0x27, 0x09, 0x7a, 0x10,
+                    0x49, 0xe6, 0x17, 0xd9, 0x1d, 0x36, 0x10, 0x94,
+                    0xfa, 0x68, 0xf0, 0xff, 0x77, 0x98, 0x71, 0x30,
+                    0x30, 0x5b, 0xea, 0xba, 0x2e, 0xda, 0x04, 0xdf,
+                    0x99, 0x7b, 0x71, 0x4d, 0x6c, 0x6f, 0x2c, 0x29,
+                    0xa6, 0xad, 0x5c, 0xb4, 0x02, 0x2b, 0x02, 0x70,
+                    0x9b},
+    .authdata    = {0xf3, 0x33, 0x88, 0x86, 0x00, 0x00, 0x00, 0x00,
+                    0x00, 0x00, 0x4e, 0x91},
+    .iv          = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08},
+    .tag         = {0xee, 0xad, 0x9d, 0x67, 0x89, 0x0c, 0xbb, 0x22,
+                    0x39, 0x23, 0x36, 0xfe, 0xa1, 0x85, 0x1f, 0x38},
+    .authsize    = 12,
+    .datasize    = 265,
+    .tagsize     = 16,
+    .ivsize      = 8
+};
+
+TestVector testVector;
+
+ChaChaPoly chachapoly;
+
+byte buffer[MAX_PLAINTEXT_LEN];
+
+bool testCipher_N(ChaChaPoly *cipher, const struct TestVector *test, size_t inc)
+{
+    size_t posn, len;
+    uint8_t tag[16];
+
+    cipher->clear();
+    if (!cipher->setKey(test->key, 32)) {
+        Serial.print("setKey ");
+        return false;
+    }
+    if (!cipher->setIV(test->iv, test->ivsize)) {
+        Serial.print("setIV ");
+        return false;
+    }
+
+    memset(buffer, 0xBA, sizeof(buffer));
+
+    for (posn = 0; posn < test->authsize; posn += inc) {
+        len = test->authsize - posn;
+        if (len > inc)
+            len = inc;
+        cipher->addAuthData(test->authdata + posn, len);
+    }
+
+    for (posn = 0; posn < test->datasize; posn += inc) {
+        len = test->datasize - posn;
+        if (len > inc)
+            len = inc;
+        cipher->encrypt(buffer + posn, test->plaintext + posn, len);
+    }
+
+    if (memcmp(buffer, test->ciphertext, test->datasize) != 0) {
+        Serial.print(buffer[0], HEX);
+        Serial.print("->");
+        Serial.print(test->ciphertext[0], HEX);
+        return false;
+    }
+
+    cipher->computeTag(tag, sizeof(tag));
+    if (memcmp(tag, test->tag, sizeof(tag)) != 0) {
+        Serial.print("computed wrong tag ... ");
+        return false;
+    }
+
+    cipher->setKey(test->key, 32);
+    cipher->setIV(test->iv, test->ivsize);
+
+    for (posn = 0; posn < test->authsize; posn += inc) {
+        len = test->authsize - posn;
+        if (len > inc)
+            len = inc;
+        cipher->addAuthData(test->authdata + posn, len);
+    }
+
+    for (posn = 0; posn < test->datasize; posn += inc) {
+        len = test->datasize - posn;
+        if (len > inc)
+            len = inc;
+        cipher->decrypt(buffer + posn, test->ciphertext + posn, len);
+    }
+
+    if (memcmp(buffer, test->plaintext, test->datasize) != 0)
+        return false;
+
+    if (!cipher->checkTag(tag, sizeof(tag))) {
+        Serial.print("tag did not check ... ");
+        return false;
+    }
+
+    return true;
+}
+
+void testCipher(ChaChaPoly *cipher, const struct TestVector *test)
+{
+    bool ok;
+
+    memcpy_P(&testVector, test, sizeof(TestVector));
+    test = &testVector;
+
+    Serial.print(test->name);
+    Serial.print(" ... ");
+
+    ok  = testCipher_N(cipher, test, test->datasize);
+    ok &= testCipher_N(cipher, test, 1);
+    ok &= testCipher_N(cipher, test, 2);
+    ok &= testCipher_N(cipher, test, 5);
+    ok &= testCipher_N(cipher, test, 8);
+    ok &= testCipher_N(cipher, test, 13);
+    ok &= testCipher_N(cipher, test, 16);
+
+    if (ok)
+        Serial.println("Passed");
+    else
+        Serial.println("Failed");
+}
+
+void perfCipherSetKey(ChaChaPoly *cipher, const struct TestVector *test)
+{
+    unsigned long start;
+    unsigned long elapsed;
+    int count;
+
+    memcpy_P(&testVector, test, sizeof(TestVector));
+    test = &testVector;
+
+    Serial.print(test->name);
+    Serial.print(" SetKey ... ");
+
+    start = micros();
+    for (count = 0; count < 1000; ++count) {
+        cipher->setKey(test->key, 32);
+        cipher->setIV(test->iv, test->ivsize);
+    }
+    elapsed = micros() - start;
+
+    Serial.print(elapsed / 1000.0);
+    Serial.print("us per operation, ");
+    Serial.print((1000.0 * 1000000.0) / elapsed);
+    Serial.println(" per second");
+}
+
+void perfCipherEncrypt(ChaChaPoly *cipher, const struct TestVector *test)
+{
+    unsigned long start;
+    unsigned long elapsed;
+    int count;
+
+    memcpy_P(&testVector, test, sizeof(TestVector));
+    test = &testVector;
+
+    Serial.print(test->name);
+    Serial.print(" Encrypt ... ");
+
+    cipher->setKey(test->key, 32);
+    cipher->setIV(test->iv, test->ivsize);
+    start = micros();
+    for (count = 0; count < 500; ++count) {
+        cipher->encrypt(buffer, buffer, 128);
+    }
+    elapsed = micros() - start;
+
+    Serial.print(elapsed / (128.0 * 500.0));
+    Serial.print("us per byte, ");
+    Serial.print((128.0 * 500.0 * 1000000.0) / elapsed);
+    Serial.println(" bytes per second");
+}
+
+void perfCipherDecrypt(ChaChaPoly *cipher, const struct TestVector *test)
+{
+    unsigned long start;
+    unsigned long elapsed;
+    int count;
+
+    memcpy_P(&testVector, test, sizeof(TestVector));
+    test = &testVector;
+
+    Serial.print(test->name);
+    Serial.print(" Decrypt ... ");
+
+    cipher->setKey(test->key, 32);
+    cipher->setIV(test->iv, test->ivsize);
+    start = micros();
+    for (count = 0; count < 500; ++count) {
+        cipher->decrypt(buffer, buffer, 128);
+    }
+    elapsed = micros() - start;
+
+    Serial.print(elapsed / (128.0 * 500.0));
+    Serial.print("us per byte, ");
+    Serial.print((128.0 * 500.0 * 1000000.0) / elapsed);
+    Serial.println(" bytes per second");
+}
+
+void perfCipherAddAuthData(ChaChaPoly *cipher, const struct TestVector *test)
+{
+    unsigned long start;
+    unsigned long elapsed;
+    int count;
+
+    memcpy_P(&testVector, test, sizeof(TestVector));
+    test = &testVector;
+
+    Serial.print(test->name);
+    Serial.print(" AddAuthData ... ");
+
+    cipher->setKey(test->key, 32);
+    cipher->setIV(test->iv, test->ivsize);
+    start = micros();
+    memset(buffer, 0xBA, 128);
+    for (count = 0; count < 500; ++count) {
+        cipher->addAuthData(buffer, 128);
+    }
+    elapsed = micros() - start;
+
+    Serial.print(elapsed / (128.0 * 500.0));
+    Serial.print("us per byte, ");
+    Serial.print((128.0 * 500.0 * 1000000.0) / elapsed);
+    Serial.println(" bytes per second");
+}
+
+/*
+void perfCipherComputeTag(ChaChaPoly *cipher, const struct TestVector *test)
+{
+    unsigned long start;
+    unsigned long elapsed;
+    int count;
+
+    memcpy_P(&testVector, test, sizeof(TestVector));
+    test = &testVector;
+
+    Serial.print(test->name);
+    Serial.print(" ComputeTag ... ");
+
+    cipher->setKey(test->key, 32);
+    cipher->setIV(test->iv, test->ivsize);
+    start = micros();
+    for (count = 0; count < 1000; ++count) {
+        cipher->computeTag(buffer, 16);
+    }
+    elapsed = micros() - start;
+
+    Serial.print(elapsed / 1000.0);
+    Serial.print("us per operation, ");
+    Serial.print((1000.0 * 1000000.0) / elapsed);
+    Serial.println(" per second");
+}
+*/
+
+void perfCipher(ChaChaPoly *cipher, const struct TestVector *test)
+{
+    perfCipherSetKey(cipher, test);
+    perfCipherEncrypt(cipher, test);
+    perfCipherDecrypt(cipher, test);
+    perfCipherAddAuthData(cipher, test);
+    //perfCipherComputeTag(cipher, test);
+}
+
+void setup()
+{
+    Serial.begin(9600);
+
+    Serial.println();
+
+    Serial.print("State Size ... ");
+    Serial.println(sizeof(ChaChaPoly));
+    Serial.println();
+
+    Serial.println("Test Vectors:");
+    testCipher(&chachapoly, &testVectorChaChaPoly_1);
+    testCipher(&chachapoly, &testVectorChaChaPoly_2);
+
+    Serial.println();
+
+    Serial.println("Performance Tests:");
+    perfCipher(&chachapoly, &testVectorChaChaPoly_1);
+}
+
+void loop()
+{
+}