diff options
Diffstat (limited to 'crypto/src')
| -rw-r--r-- | crypto/src/crypto/engines/ElephantEngine.cs | 181 |
1 files changed, 120 insertions, 61 deletions
diff --git a/crypto/src/crypto/engines/ElephantEngine.cs b/crypto/src/crypto/engines/ElephantEngine.cs index b0ec4733c..e3d9ca670 100644 --- a/crypto/src/crypto/engines/ElephantEngine.cs +++ b/crypto/src/crypto/engines/ElephantEngine.cs @@ -12,7 +12,7 @@ using Org.BouncyCastle.Utilities; */ namespace Org.BouncyCastle.Crypto.Engines { - public class ElephantEngine : IAeadCipher + public class ElephantEngine : IAeadBlockCipher { public enum ElephantParameters { @@ -20,23 +20,23 @@ namespace Org.BouncyCastle.Crypto.Engines elephant176, elephant200 } - + private bool forEncryption; + private readonly string algorithmName; private ElephantParameters parameters; private int BLOCK_SIZE; private int nBits; private int nSBox; private int nRounds; private byte lfsrIV; - private byte[] m; private byte[] npub; private byte[] expanded_key; - private byte[] tag_buffer; + private byte[] tag; private byte CRYPTO_KEYBYTES = 16; private byte CRYPTO_NPUBBYTES = 12; private byte CRYPTO_ABYTES; + private bool initialised; private MemoryStream aadData = new MemoryStream(); - private bool encrypted; - private bool aadFinished; + private MemoryStream message = new MemoryStream(); private readonly byte[] sBoxLayer = { (byte)0xee, (byte)0xed, (byte)0xeb, (byte)0xe0, (byte)0xe2, (byte)0xe1, (byte)0xe4, (byte)0xef, (byte)0xe7, (byte)0xea, (byte)0xe8, (byte)0xe5, (byte)0xe9, (byte)0xec, (byte)0xe3, (byte)0xe6, @@ -75,6 +75,7 @@ namespace Org.BouncyCastle.Crypto.Engines nRounds = 80; lfsrIV = 0x75; CRYPTO_ABYTES = 8; + algorithmName = "Elephant 160 AEAD"; break; case ElephantParameters.elephant176: BLOCK_SIZE = 22; @@ -83,15 +84,19 @@ namespace Org.BouncyCastle.Crypto.Engines nRounds = 90; lfsrIV = 0x45; CRYPTO_ABYTES = 8; + algorithmName = "Elephant 176 AEAD"; break; case ElephantParameters.elephant200: BLOCK_SIZE = 25; nRounds = 18; CRYPTO_ABYTES = 16; + algorithmName = "Elephant 200 AEAD"; break; + default: + throw new ArgumentException("Invalid parameter settings for Elephant"); } this.parameters = parameters; - tag_buffer = new byte[BLOCK_SIZE]; + initialised = false; reset(false); } @@ -157,7 +162,7 @@ namespace Org.BouncyCastle.Crypto.Engines return x + y * 5; } - void KeccakP200Round(byte[] state, int indexRound) + private void KeccakP200Round(byte[] state, int indexRound) { int x, y; byte[] tempA = new byte[25]; @@ -215,7 +220,7 @@ namespace Org.BouncyCastle.Crypto.Engines // State should be BLOCK_SIZE bytes long // Note: input may be equal to output - void lfsr_step(byte[] output, byte[] input) + private void lfsr_step(byte[] output, byte[] input) { switch (parameters) { @@ -233,7 +238,7 @@ namespace Org.BouncyCastle.Crypto.Engines Array.Copy(input, 1, output, 0, BLOCK_SIZE - 1); } - void xor_block(byte[] state, byte[] block, int bOff, int size) + private void xor_block(byte[] state, byte[] block, int bOff, int size) { for (int i = 0; i < size; ++i) { @@ -244,7 +249,7 @@ namespace Org.BouncyCastle.Crypto.Engines // Write the ith assocated data block to "output". // The nonce is prepended and padding is added as required. // adlen is the length of the associated data in bytes - void get_ad_block(byte[] output, byte[] ad, int adlen, byte[] npub, int i) + private void get_ad_block(byte[] output, byte[] ad, int adlen, byte[] npub, int i) { int len = 0; // First block contains nonce @@ -282,9 +287,9 @@ namespace Org.BouncyCastle.Crypto.Engines // Return the ith ciphertext block. // clen is the length of the ciphertext in bytes - void get_c_block(byte[] output, byte[] c, int cOff, int clen, int i) + private void get_c_block(byte[] output, byte[] c, int cOff, int clen, int i) { - int block_offset = cOff + i * BLOCK_SIZE; + int block_offset = i * BLOCK_SIZE; // If clen is divisible by BLOCK_SIZE, add an additional padding block if (block_offset == clen) { @@ -296,13 +301,13 @@ namespace Org.BouncyCastle.Crypto.Engines // Fill with ciphertext if available if (BLOCK_SIZE <= r_clen) { // enough ciphertext - Array.Copy(c, block_offset, output, 0, BLOCK_SIZE); + Array.Copy(c, cOff + block_offset, output, 0, BLOCK_SIZE); } else { // not enough ciphertext, need to pad if (r_clen > 0) // c might be nullptr { - Array.Copy(c, block_offset, output, 0, r_clen); + Array.Copy(c, cOff + block_offset, output, 0, r_clen); } Arrays.Fill(output, r_clen, BLOCK_SIZE, (byte)0); output[r_clen] = 0x01; @@ -313,10 +318,7 @@ namespace Org.BouncyCastle.Crypto.Engines public void Init(bool forEncryption, ICipherParameters param) { - /** - * Elephant encryption and decryption is completely symmetrical, so the - * 'forEncryption' is irrelevant. - */ + this.forEncryption = forEncryption; if (!(param is ParametersWithIV)) { throw new ArgumentException( @@ -350,10 +352,14 @@ namespace Org.BouncyCastle.Crypto.Engines expanded_key = new byte[BLOCK_SIZE]; Array.Copy(k, 0, expanded_key, 0, CRYPTO_KEYBYTES); permutation(expanded_key); + initialised = true; + reset(false); } - public string AlgorithmName => "Elephant AEAD"; + public string AlgorithmName => algorithmName; + + public IBlockCipher UnderlyingCipher => throw new NotImplementedException(); public void ProcessAadByte(byte input) { @@ -363,26 +369,48 @@ namespace Org.BouncyCastle.Crypto.Engines public void ProcessAadBytes(byte[] input, int inOff, int len) { + if (inOff + len > input.Length) + { + throw new DataLengthException("input buffer too short"); + } aadData.Write(input, inOff, len); } public int ProcessByte(byte input, byte[] output, int outOff) { - return ProcessBytes(new byte[] { input }, 0, 1, output, outOff); + message.Write(new byte[] { input }, 0, 1); + return 0; } public int ProcessBytes(byte[] input, int inOff, int len, byte[] output, int outOff) { - if (encrypted) + if (inOff + len > input.Length) + { + throw new DataLengthException("input buffer too short"); + } + message.Write(input, inOff, len); + return 0; + } + + + public int DoFinal(byte[] output, int outOff) + { + if (!initialised) + { + throw new ArgumentException("Need call init function before encryption/decryption"); + } + int mlen = (int)message.Length - (forEncryption ? 0 : CRYPTO_ABYTES); + if ((forEncryption && mlen + outOff + CRYPTO_ABYTES > output.Length) || + (!forEncryption && mlen + outOff - CRYPTO_ABYTES > output.Length)) { - throw new ArgumentException("Encryption has been processed"); + throw new OutputLengthException("output buffer is too short"); } - m = new byte[len]; - Array.Copy(input, inOff, m, 0, len); + byte[] tag_buffer = new byte[BLOCK_SIZE]; + byte[] m = message.GetBuffer(); byte[] ad = aadData.GetBuffer(); - int mlen = len, adlen = (int)aadData.Length; + int adlen = (int)aadData.Length; int nblocks_c = 1 + mlen / BLOCK_SIZE; int nblocks_m = (mlen % BLOCK_SIZE) != 0 ? nblocks_c : nblocks_c - 1; int nblocks_ad = 1 + (CRYPTO_NPUBBYTES + adlen) / BLOCK_SIZE; @@ -415,11 +443,17 @@ namespace Org.BouncyCastle.Crypto.Engines xor_block(buffer, m, offset, r_size); Array.Copy(buffer, 0, output, offset + outOff, r_size); } - if (i > 0 && i <= nblocks_c) { // Compute tag for ciphertext block - get_c_block(buffer, output, outOff, mlen, i - 1);//encrypt != 0 ? c : m + if (forEncryption) + { + get_c_block(buffer, output, outOff, mlen, i - 1); + } + else + { + get_c_block(buffer, m, 0, mlen, i - 1); + } xor_block(buffer, previous_mask, 0, BLOCK_SIZE); xor_block(buffer, next_mask, 0, BLOCK_SIZE); permutation(buffer); @@ -444,30 +478,34 @@ namespace Org.BouncyCastle.Crypto.Engines next_mask = temp; offset += BLOCK_SIZE; } - encrypted = true; - return 0; - } - - - public int DoFinal(byte[] output, int outOff) - { - byte[] tag = GetMac(); - Array.Copy(tag, 0, output, outOff, tag.Length); + outOff += mlen; + tag = new byte[CRYPTO_ABYTES]; + xor_block(tag_buffer, expanded_key, 0, BLOCK_SIZE); + permutation(tag_buffer); + xor_block(tag_buffer, expanded_key, 0, BLOCK_SIZE); + if (forEncryption) + { + Array.Copy(tag_buffer, 0, tag, 0, CRYPTO_ABYTES); + Array.Copy(tag, 0, output, outOff, tag.Length); + mlen += CRYPTO_ABYTES; + } + else + { + for (int i = 0; i < CRYPTO_ABYTES; ++i) + { + if (tag_buffer[i] != m[mlen + i]) + { + throw new ArgumentException("Mac does not match"); + } + } + } reset(false); - return 0; + return mlen; } public byte[] GetMac() { - byte[] tag = new byte[CRYPTO_ABYTES]; - if (!aadFinished) - { - xor_block(tag_buffer, expanded_key, 0, BLOCK_SIZE); - permutation(tag_buffer); - xor_block(tag_buffer, expanded_key, 0, BLOCK_SIZE); - } - Array.Copy(tag_buffer, 0, tag, 0, CRYPTO_ABYTES); return tag; } @@ -493,11 +531,12 @@ namespace Org.BouncyCastle.Crypto.Engines { if (clearMac) { - aadData.SetLength(0); + tag = null; } - encrypted = false; - aadFinished = false; + aadData.SetLength(0); + message.SetLength(0); } + #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER public void ProcessAadBytes(ReadOnlySpan<byte> input) { @@ -506,28 +545,48 @@ namespace Org.BouncyCastle.Crypto.Engines public int ProcessByte(byte input, Span<byte> output) { - byte[] rv = new byte[1]; - ProcessBytes(new byte[] { input }, 0, 1, rv, 0); - rv.AsSpan(0, 1).CopyTo(output); - return 1; + message.Write(new byte[] { input }); + return 0; } public int ProcessBytes(ReadOnlySpan<byte> input, Span<byte> output) { - byte[] rv = new byte[input.Length]; - ProcessBytes(input.ToArray(), 0, rv.Length, rv, 0); - rv.AsSpan(0, rv.Length).CopyTo(output); - return rv.Length; + message.Write(input.ToArray()); + return 0; } public int DoFinal(Span<byte> output) { - byte[] tag = GetMac(); - tag.AsSpan(0, tag.Length).CopyTo(output); - reset(false); - return tag.Length; + byte[] rv; + if (forEncryption) + { + rv = new byte[message.Length + CRYPTO_ABYTES]; + } + else + { + rv = new byte[message.Length - CRYPTO_ABYTES]; + } + int len = DoFinal(rv, 0); + rv.AsSpan(0, len).CopyTo(output); + return rv.Length; + } #endif + + public int GetKeyBytesSize() + { + return CRYPTO_KEYBYTES; + } + + public int GetIVBytesSize() + { + return CRYPTO_NPUBBYTES; + } + + public int GetBlockSize() + { + return BLOCK_SIZE; + } } } |