Add crypto sources for future use.add/crypto

 * the goal is to support AES-CBC-HMAC-SHA as AEAD cipher

Signed-off-by: Toni Uhlig <matzeton@googlemail.com>

10 files changed, 1417 insertions, 5 deletions

diff --git a/Makefile b/Makefile
index 357c19a..7269dcf 100644
--- a/Makefile
+++ b/Makefile
@@ -4,16 +4,27 @@ endif
 
 include $(DPP_ROOT)/Makefile.inc
 
+SOCKET_HEADERS = ksocket/berkeley.h ksocket/helper.hpp ksocket/ksocket.h ksocket/wsk.h
+SOCKET_OBJECTS = ksocket/ksocket.o ksocket/berkeley.o
+
+PROTOB_HEADERS = protobuf-c/protobuf-c.h
+PROTOB_OBJECTS = protobuf-c/protobuf-c.o
+
+CRYPTO_HEADERS =
+CRYPTO_OBJECTS = crypto/aes.o crypto/hmac.o crypto/sha1.o crypto/pkcs7_padding.o
+
+STATIC_LIB_OBJS = $(SOCKET_OBJECTS) $(PROTOB_OBJECTS) $(CRYPTO_OBJECTS)
+
 DRIVER0_NAME = driver
-DRIVER0_OBJECTS = examples/$(DRIVER0_NAME).o ksocket/ksocket.o ksocket/berkeley.o
+DRIVER0_OBJECTS = examples/$(DRIVER0_NAME).o $(SOCKET_OBJECTS)
 DRIVER0_TARGET = $(DRIVER0_NAME).sys
 
 DRIVER1_NAME = driver-protobuf-c
-DRIVER1_OBJECTS = examples/$(DRIVER1_NAME).o protobuf-c/protobuf-c.o examples/example.pb-c.o
+DRIVER1_OBJECTS = examples/$(DRIVER1_NAME).o $(PROTOB_OBJECTS) examples/example.pb-c.o
 DRIVER1_TARGET = $(DRIVER1_NAME).sys
 
 DRIVER2_NAME = driver-protobuf-c-tcp
-DRIVER2_OBJECTS = examples/$(DRIVER2_NAME).o ksocket/ksocket.o ksocket/berkeley.o protobuf-c/protobuf-c.o examples/example.pb-c.o
+DRIVER2_OBJECTS = examples/$(DRIVER2_NAME).o $(SOCKET_OBJECTS) $(PROTOB_OBJECTS) examples/example.pb-c.o
 DRIVER2_TARGET = $(DRIVER2_NAME).sys
 
 USERSPACE0_NAME = userspace_client
@@ -21,7 +32,7 @@ USERSPACE0_OBJECTS = examples/$(USERSPACE0_NAME).o
 USERSPACE0_TARGET = $(USERSPACE0_NAME).exe
 
 USERSPACE1_NAME = userspace_client_protobuf
-USERSPACE1_OBJECTS = examples/$(USERSPACE1_NAME).o protobuf-c/protobuf-c.o examples/example.pb-c.o
+USERSPACE1_OBJECTS = examples/$(USERSPACE1_NAME).o $(PROTOB_OBJECTS) examples/example.pb-c.o
 USERSPACE1_TARGET = $(USERSPACE1_NAME).exe
 
 # mingw-w64-dpp related
@@ -71,7 +82,13 @@ install: $(DRIVER0_TARGET) $(DRIVER1_TARGET) $(DRIVER2_TARGET) $(USERSPACE0_TARG
 	$(INSTALL) 'examples/$(DRIVER1_NAME).bat' '$(DESTDIR)/'
 	$(INSTALL) 'examples/$(DRIVER2_NAME).bat' '$(DESTDIR)/'
 
+package: $(SOCKET_HEADERS) $(PROTOB_HEADERS) $(STATIC_LIB_OBJS)
+	$(call INSTALL_HEADERS,ksocket,$(SOCKET_HEADERS),package)
+	$(call INSTALL_HEADERS,protobuf-c,$(PROTOB_HEADERS),package)
+	$(call PACKAGE,ksocket,$(STATIC_LIB_OBJS),package)
+
 clean:
+	rm -f $(STATIC_LIB_OBJS)
 	rm -f $(DRIVER0_OBJECTS) $(DRIVER1_OBJECTS) $(DRIVER2_OBJECTS)
 	rm -f $(DRIVER0_TARGET) $(DRIVER0_TARGET).map \
 		$(DRIVER1_TARGET) $(DRIVER1_TARGET).map \
@@ -80,5 +97,5 @@ clean:
 	rm -f $(USERSPACE0_TARGET) $(USERSPACE1_TARGET)
 
 .NOTPARALLEL: clean
-.PHONY: all install clean
+.PHONY: all install package clean
 .DEFAULT_GOAL := all
diff --git a/crypto/aes.c b/crypto/aes.c
new file mode 100644
index 0000000..4481f7b
--- /dev/null
+++ b/crypto/aes.c
@@ -0,0 +1,572 @@
+/*
+
+This is an implementation of the AES algorithm, specifically ECB, CTR and CBC mode.
+Block size can be chosen in aes.h - available choices are AES128, AES192, AES256.
+
+The implementation is verified against the test vectors in:
+  National Institute of Standards and Technology Special Publication 800-38A 2001 ED
+
+ECB-AES128
+----------
+
+  plain-text:
+    6bc1bee22e409f96e93d7e117393172a
+    ae2d8a571e03ac9c9eb76fac45af8e51
+    30c81c46a35ce411e5fbc1191a0a52ef
+    f69f2445df4f9b17ad2b417be66c3710
+
+  key:
+    2b7e151628aed2a6abf7158809cf4f3c
+
+  resulting cipher
+    3ad77bb40d7a3660a89ecaf32466ef97 
+    f5d3d58503b9699de785895a96fdbaaf 
+    43b1cd7f598ece23881b00e3ed030688 
+    7b0c785e27e8ad3f8223207104725dd4 
+
+
+NOTE:   String length must be evenly divisible by 16byte (str_len % 16 == 0)
+        You should pad the end of the string with zeros if this is not the case.
+        For AES192/256 the key size is proportionally larger.
+
+*/
+
+
+/*****************************************************************************/
+/* Includes:                                                                 */
+/*****************************************************************************/
+#include <string.h> // CBC mode, for memset
+#include "aes.h"
+
+/*****************************************************************************/
+/* Defines:                                                                  */
+/*****************************************************************************/
+// The number of columns comprising a state in AES. This is a constant in AES. Value=4
+#define Nb 4
+
+#if defined(AES256) && (AES256 == 1)
+    #define Nk 8
+    #define Nr 14
+#elif defined(AES192) && (AES192 == 1)
+    #define Nk 6
+    #define Nr 12
+#else
+    #define Nk 4        // The number of 32 bit words in a key.
+    #define Nr 10       // The number of rounds in AES Cipher.
+#endif
+
+// jcallan@github points out that declaring Multiply as a function 
+// reduces code size considerably with the Keil ARM compiler.
+// See this link for more information: https://github.com/kokke/tiny-AES-C/pull/3
+#ifndef MULTIPLY_AS_A_FUNCTION
+  #define MULTIPLY_AS_A_FUNCTION 0
+#endif
+
+
+
+
+/*****************************************************************************/
+/* Private variables:                                                        */
+/*****************************************************************************/
+// state - array holding the intermediate results during decryption.
+typedef uint8_t state_t[4][4];
+
+
+
+// The lookup-tables are marked const so they can be placed in read-only storage instead of RAM
+// The numbers below can be computed dynamically trading ROM for RAM - 
+// This can be useful in (embedded) bootloader applications, where ROM is often limited.
+static const uint8_t sbox[256] = {
+  //0     1    2      3     4    5     6     7      8    9     A      B    C     D     E     F
+  0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
+  0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
+  0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
+  0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
+  0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
+  0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
+  0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
+  0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
+  0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
+  0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
+  0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
+  0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
+  0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
+  0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
+  0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
+  0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 };
+
+#if (defined(CBC) && CBC == 1) || (defined(ECB) && ECB == 1)
+static const uint8_t rsbox[256] = {
+  0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
+  0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
+  0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
+  0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
+  0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
+  0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
+  0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
+  0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
+  0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
+  0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
+  0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
+  0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
+  0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
+  0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
+  0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
+  0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d };
+#endif
+
+// The round constant word array, Rcon[i], contains the values given by 
+// x to the power (i-1) being powers of x (x is denoted as {02}) in the field GF(2^8)
+static const uint8_t Rcon[11] = {
+  0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 };
+
+/*
+ * Jordan Goulder points out in PR #12 (https://github.com/kokke/tiny-AES-C/pull/12),
+ * that you can remove most of the elements in the Rcon array, because they are unused.
+ *
+ * From Wikipedia's article on the Rijndael key schedule @ https://en.wikipedia.org/wiki/Rijndael_key_schedule#Rcon
+ * 
+ * "Only the first some of these constants are actually used – up to rcon[10] for AES-128 (as 11 round keys are needed), 
+ *  up to rcon[8] for AES-192, up to rcon[7] for AES-256. rcon[0] is not used in AES algorithm."
+ */
+
+
+/*****************************************************************************/
+/* Private functions:                                                        */
+/*****************************************************************************/
+/*
+static uint8_t getSBoxValue(uint8_t num)
+{
+  return sbox[num];
+}
+*/
+#define getSBoxValue(num) (sbox[(num)])
+
+// This function produces Nb(Nr+1) round keys. The round keys are used in each round to decrypt the states. 
+static void KeyExpansion(uint8_t* RoundKey, const uint8_t* Key)
+{
+  unsigned i, j, k;
+  uint8_t tempa[4]; // Used for the column/row operations
+  
+  // The first round key is the key itself.
+  for (i = 0; i < Nk; ++i)
+  {
+    RoundKey[(i * 4) + 0] = Key[(i * 4) + 0];
+    RoundKey[(i * 4) + 1] = Key[(i * 4) + 1];
+    RoundKey[(i * 4) + 2] = Key[(i * 4) + 2];
+    RoundKey[(i * 4) + 3] = Key[(i * 4) + 3];
+  }
+
+  // All other round keys are found from the previous round keys.
+  for (i = Nk; i < Nb * (Nr + 1); ++i)
+  {
+    {
+      k = (i - 1) * 4;
+      tempa[0]=RoundKey[k + 0];
+      tempa[1]=RoundKey[k + 1];
+      tempa[2]=RoundKey[k + 2];
+      tempa[3]=RoundKey[k + 3];
+
+    }
+
+    if (i % Nk == 0)
+    {
+      // This function shifts the 4 bytes in a word to the left once.
+      // [a0,a1,a2,a3] becomes [a1,a2,a3,a0]
+
+      // Function RotWord()
+      {
+        const uint8_t u8tmp = tempa[0];
+        tempa[0] = tempa[1];
+        tempa[1] = tempa[2];
+        tempa[2] = tempa[3];
+        tempa[3] = u8tmp;
+      }
+
+      // SubWord() is a function that takes a four-byte input word and 
+      // applies the S-box to each of the four bytes to produce an output word.
+
+      // Function Subword()
+      {
+        tempa[0] = getSBoxValue(tempa[0]);
+        tempa[1] = getSBoxValue(tempa[1]);
+        tempa[2] = getSBoxValue(tempa[2]);
+        tempa[3] = getSBoxValue(tempa[3]);
+      }
+
+      tempa[0] = tempa[0] ^ Rcon[i/Nk];
+    }
+#if defined(AES256) && (AES256 == 1)
+    if (i % Nk == 4)
+    {
+      // Function Subword()
+      {
+        tempa[0] = getSBoxValue(tempa[0]);
+        tempa[1] = getSBoxValue(tempa[1]);
+        tempa[2] = getSBoxValue(tempa[2]);
+        tempa[3] = getSBoxValue(tempa[3]);
+      }
+    }
+#endif
+    j = i * 4; k=(i - Nk) * 4;
+    RoundKey[j + 0] = RoundKey[k + 0] ^ tempa[0];
+    RoundKey[j + 1] = RoundKey[k + 1] ^ tempa[1];
+    RoundKey[j + 2] = RoundKey[k + 2] ^ tempa[2];
+    RoundKey[j + 3] = RoundKey[k + 3] ^ tempa[3];
+  }
+}
+
+void AES_init_ctx(struct AES_ctx* ctx, const uint8_t* key)
+{
+  KeyExpansion(ctx->RoundKey, key);
+}
+#if (defined(CBC) && (CBC == 1)) || (defined(CTR) && (CTR == 1))
+void AES_init_ctx_iv(struct AES_ctx* ctx, const uint8_t* key, const uint8_t* iv)
+{
+  KeyExpansion(ctx->RoundKey, key);
+  memcpy (ctx->Iv, iv, AES_BLOCKLEN);
+}
+void AES_ctx_set_iv(struct AES_ctx* ctx, const uint8_t* iv)
+{
+  memcpy (ctx->Iv, iv, AES_BLOCKLEN);
+}
+#endif
+
+// This function adds the round key to state.
+// The round key is added to the state by an XOR function.
+static void AddRoundKey(uint8_t round, state_t* state, const uint8_t* RoundKey)
+{
+  uint8_t i,j;
+  for (i = 0; i < 4; ++i)
+  {
+    for (j = 0; j < 4; ++j)
+    {
+      (*state)[i][j] ^= RoundKey[(round * Nb * 4) + (i * Nb) + j];
+    }
+  }
+}
+
+// The SubBytes Function Substitutes the values in the
+// state matrix with values in an S-box.
+static void SubBytes(state_t* state)
+{
+  uint8_t i, j;
+  for (i = 0; i < 4; ++i)
+  {
+    for (j = 0; j < 4; ++j)
+    {
+      (*state)[j][i] = getSBoxValue((*state)[j][i]);
+    }
+  }
+}
+
+// The ShiftRows() function shifts the rows in the state to the left.
+// Each row is shifted with different offset.
+// Offset = Row number. So the first row is not shifted.
+static void ShiftRows(state_t* state)
+{
+  uint8_t temp;
+
+  // Rotate first row 1 columns to left  
+  temp           = (*state)[0][1];
+  (*state)[0][1] = (*state)[1][1];
+  (*state)[1][1] = (*state)[2][1];
+  (*state)[2][1] = (*state)[3][1];
+  (*state)[3][1] = temp;
+
+  // Rotate second row 2 columns to left  
+  temp           = (*state)[0][2];
+  (*state)[0][2] = (*state)[2][2];
+  (*state)[2][2] = temp;
+
+  temp           = (*state)[1][2];
+  (*state)[1][2] = (*state)[3][2];
+  (*state)[3][2] = temp;
+
+  // Rotate third row 3 columns to left
+  temp           = (*state)[0][3];
+  (*state)[0][3] = (*state)[3][3];
+  (*state)[3][3] = (*state)[2][3];
+  (*state)[2][3] = (*state)[1][3];
+  (*state)[1][3] = temp;
+}
+
+static uint8_t xtime(uint8_t x)
+{
+  return ((x<<1) ^ (((x>>7) & 1) * 0x1b));
+}
+
+// MixColumns function mixes the columns of the state matrix
+static void MixColumns(state_t* state)
+{
+  uint8_t i;
+  uint8_t Tmp, Tm, t;
+  for (i = 0; i < 4; ++i)
+  {  
+    t   = (*state)[i][0];
+    Tmp = (*state)[i][0] ^ (*state)[i][1] ^ (*state)[i][2] ^ (*state)[i][3] ;
+    Tm  = (*state)[i][0] ^ (*state)[i][1] ; Tm = xtime(Tm);  (*state)[i][0] ^= Tm ^ Tmp ;
+    Tm  = (*state)[i][1] ^ (*state)[i][2] ; Tm = xtime(Tm);  (*state)[i][1] ^= Tm ^ Tmp ;
+    Tm  = (*state)[i][2] ^ (*state)[i][3] ; Tm = xtime(Tm);  (*state)[i][2] ^= Tm ^ Tmp ;
+    Tm  = (*state)[i][3] ^ t ;              Tm = xtime(Tm);  (*state)[i][3] ^= Tm ^ Tmp ;
+  }
+}
+
+// Multiply is used to multiply numbers in the field GF(2^8)
+// Note: The last call to xtime() is unneeded, but often ends up generating a smaller binary
+//       The compiler seems to be able to vectorize the operation better this way.
+//       See https://github.com/kokke/tiny-AES-c/pull/34
+#if MULTIPLY_AS_A_FUNCTION
+static uint8_t Multiply(uint8_t x, uint8_t y)
+{
+  return (((y & 1) * x) ^
+       ((y>>1 & 1) * xtime(x)) ^
+       ((y>>2 & 1) * xtime(xtime(x))) ^
+       ((y>>3 & 1) * xtime(xtime(xtime(x)))) ^
+       ((y>>4 & 1) * xtime(xtime(xtime(xtime(x)))))); /* this last call to xtime() can be omitted */
+  }
+#else
+#define Multiply(x, y)                                \
+      (  ((y & 1) * x) ^                              \
+      ((y>>1 & 1) * xtime(x)) ^                       \
+      ((y>>2 & 1) * xtime(xtime(x))) ^                \
+      ((y>>3 & 1) * xtime(xtime(xtime(x)))) ^         \
+      ((y>>4 & 1) * xtime(xtime(xtime(xtime(x))))))   \
+
+#endif
+
+#if (defined(CBC) && CBC == 1) || (defined(ECB) && ECB == 1)
+/*
+static uint8_t getSBoxInvert(uint8_t num)
+{
+  return rsbox[num];
+}
+*/
+#define getSBoxInvert(num) (rsbox[(num)])
+
+// MixColumns function mixes the columns of the state matrix.
+// The method used to multiply may be difficult to understand for the inexperienced.
+// Please use the references to gain more information.
+static void InvMixColumns(state_t* state)
+{
+  int i;
+  uint8_t a, b, c, d;
+  for (i = 0; i < 4; ++i)
+  { 
+    a = (*state)[i][0];
+    b = (*state)[i][1];
+    c = (*state)[i][2];
+    d = (*state)[i][3];
+
+    (*state)[i][0] = Multiply(a, 0x0e) ^ Multiply(b, 0x0b) ^ Multiply(c, 0x0d) ^ Multiply(d, 0x09);
+    (*state)[i][1] = Multiply(a, 0x09) ^ Multiply(b, 0x0e) ^ Multiply(c, 0x0b) ^ Multiply(d, 0x0d);
+    (*state)[i][2] = Multiply(a, 0x0d) ^ Multiply(b, 0x09) ^ Multiply(c, 0x0e) ^ Multiply(d, 0x0b);
+    (*state)[i][3] = Multiply(a, 0x0b) ^ Multiply(b, 0x0d) ^ Multiply(c, 0x09) ^ Multiply(d, 0x0e);
+  }
+}
+
+
+// The SubBytes Function Substitutes the values in the
+// state matrix with values in an S-box.
+static void InvSubBytes(state_t* state)
+{
+  uint8_t i, j;
+  for (i = 0; i < 4; ++i)
+  {
+    for (j = 0; j < 4; ++j)
+    {
+      (*state)[j][i] = getSBoxInvert((*state)[j][i]);
+    }
+  }
+}
+
+static void InvShiftRows(state_t* state)
+{
+  uint8_t temp;
+
+  // Rotate first row 1 columns to right  
+  temp = (*state)[3][1];
+  (*state)[3][1] = (*state)[2][1];
+  (*state)[2][1] = (*state)[1][1];
+  (*state)[1][1] = (*state)[0][1];
+  (*state)[0][1] = temp;
+
+  // Rotate second row 2 columns to right 
+  temp = (*state)[0][2];
+  (*state)[0][2] = (*state)[2][2];
+  (*state)[2][2] = temp;
+
+  temp = (*state)[1][2];
+  (*state)[1][2] = (*state)[3][2];
+  (*state)[3][2] = temp;
+
+  // Rotate third row 3 columns to right
+  temp = (*state)[0][3];
+  (*state)[0][3] = (*state)[1][3];
+  (*state)[1][3] = (*state)[2][3];
+  (*state)[2][3] = (*state)[3][3];
+  (*state)[3][3] = temp;
+}
+#endif // #if (defined(CBC) && CBC == 1) || (defined(ECB) && ECB == 1)
+
+// Cipher is the main function that encrypts the PlainText.
+static void Cipher(state_t* state, const uint8_t* RoundKey)
+{
+  uint8_t round = 0;
+
+  // Add the First round key to the state before starting the rounds.
+  AddRoundKey(0, state, RoundKey);
+
+  // There will be Nr rounds.
+  // The first Nr-1 rounds are identical.
+  // These Nr rounds are executed in the loop below.
+  // Last one without MixColumns()
+  for (round = 1; ; ++round)
+  {
+    SubBytes(state);
+    ShiftRows(state);
+    if (round == Nr) {
+      break;
+    }
+    MixColumns(state);
+    AddRoundKey(round, state, RoundKey);
+  }
+  // Add round key to last round
+  AddRoundKey(Nr, state, RoundKey);
+}
+
+#if (defined(CBC) && CBC == 1) || (defined(ECB) && ECB == 1)
+static void InvCipher(state_t* state, const uint8_t* RoundKey)
+{
+  uint8_t round = 0;
+
+  // Add the First round key to the state before starting the rounds.
+  AddRoundKey(Nr, state, RoundKey);
+
+  // There will be Nr rounds.
+  // The first Nr-1 rounds are identical.
+  // These Nr rounds are executed in the loop below.
+  // Last one without InvMixColumn()
+  for (round = (Nr - 1); ; --round)
+  {
+    InvShiftRows(state);
+    InvSubBytes(state);
+    AddRoundKey(round, state, RoundKey);
+    if (round == 0) {
+      break;
+    }
+    InvMixColumns(state);
+  }
+
+}
+#endif // #if (defined(CBC) && CBC == 1) || (defined(ECB) && ECB == 1)
+
+/*****************************************************************************/
+/* Public functions:                                                         */
+/*****************************************************************************/
+#if defined(ECB) && (ECB == 1)
+
+
+void AES_ECB_encrypt(const struct AES_ctx* ctx, uint8_t* buf)
+{
+  // The next function call encrypts the PlainText with the Key using AES algorithm.
+  Cipher((state_t*)buf, ctx->RoundKey);
+}
+
+void AES_ECB_decrypt(const struct AES_ctx* ctx, uint8_t* buf)
+{
+  // The next function call decrypts the PlainText with the Key using AES algorithm.
+  InvCipher((state_t*)buf, ctx->RoundKey);
+}
+
+
+#endif // #if defined(ECB) && (ECB == 1)
+
+
+
+
+
+#if defined(CBC) && (CBC == 1)
+
+
+static void XorWithIv(uint8_t* buf, const uint8_t* Iv)
+{
+  uint8_t i;
+  for (i = 0; i < AES_BLOCKLEN; ++i) // The block in AES is always 128bit no matter the key size
+  {
+    buf[i] ^= Iv[i];
+  }
+}
+
+void AES_CBC_encrypt_buffer(struct AES_ctx *ctx, uint8_t* buf, size_t length)
+{
+  size_t i;
+  uint8_t *Iv = ctx->Iv;
+  for (i = 0; i < length; i += AES_BLOCKLEN)
+  {
+    XorWithIv(buf, Iv);
+    Cipher((state_t*)buf, ctx->RoundKey);
+    Iv = buf;
+    buf += AES_BLOCKLEN;
+  }
+  /* store Iv in ctx for next call */
+  memcpy(ctx->Iv, Iv, AES_BLOCKLEN);
+}
+
+void AES_CBC_decrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, size_t length)
+{
+  size_t i;
+  uint8_t storeNextIv[AES_BLOCKLEN];
+  for (i = 0; i < length; i += AES_BLOCKLEN)
+  {
+    memcpy(storeNextIv, buf, AES_BLOCKLEN);
+    InvCipher((state_t*)buf, ctx->RoundKey);
+    XorWithIv(buf, ctx->Iv);
+    memcpy(ctx->Iv, storeNextIv, AES_BLOCKLEN);
+    buf += AES_BLOCKLEN;
+  }
+
+}
+
+#endif // #if defined(CBC) && (CBC == 1)
+
+
+
+#if defined(CTR) && (CTR == 1)
+
+/* Symmetrical operation: same function for encrypting as for decrypting. Note any IV/nonce should never be reused with the same key */
+void AES_CTR_xcrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, size_t length)
+{
+  uint8_t buffer[AES_BLOCKLEN];
+  
+  size_t i;
+  int bi;
+  for (i = 0, bi = AES_BLOCKLEN; i < length; ++i, ++bi)
+  {
+    if (bi == AES_BLOCKLEN) /* we need to regen xor compliment in buffer */
+    {
+      
+      memcpy(buffer, ctx->Iv, AES_BLOCKLEN);
+      Cipher((state_t*)buffer,ctx->RoundKey);
+
+      /* Increment Iv and handle overflow */
+      for (bi = (AES_BLOCKLEN - 1); bi >= 0; --bi)
+      {
+	/* inc will overflow */
+        if (ctx->Iv[bi] == 255)
+	{
+          ctx->Iv[bi] = 0;
+          continue;
+        } 
+        ctx->Iv[bi] += 1;
+        break;   
+      }
+      bi = 0;
+    }
+
+    buf[i] = (buf[i] ^ buffer[bi]);
+  }
+}
+
+#endif // #if defined(CTR) && (CTR == 1)
+
diff --git a/crypto/aes.h b/crypto/aes.h
new file mode 100644
index 0000000..b29b668
--- /dev/null
+++ b/crypto/aes.h
@@ -0,0 +1,91 @@
+#ifndef _AES_H_
+#define _AES_H_
+
+#include <stdint.h>
+#include <stddef.h>
+
+// #define the macros below to 1/0 to enable/disable the mode of operation.
+//
+// CBC enables AES encryption in CBC-mode of operation.
+// CTR enables encryption in counter-mode.
+// ECB enables the basic ECB 16-byte block algorithm. All can be enabled simultaneously.
+
+// The #ifndef-guard allows it to be configured before #include'ing or at compile time.
+#ifndef CBC
+  #define CBC 1
+#endif
+
+#ifndef ECB
+  #define ECB 1
+#endif
+
+#ifndef CTR
+  #define CTR 1
+#endif
+
+
+#define AES128 1
+//#define AES192 1
+//#define AES256 1
+
+#define AES_BLOCKLEN 16 // Block length in bytes - AES is 128b block only
+
+#if defined(AES256) && (AES256 == 1)
+    #define AES_KEYLEN 32
+    #define AES_keyExpSize 240
+#elif defined(AES192) && (AES192 == 1)
+    #define AES_KEYLEN 24
+    #define AES_keyExpSize 208
+#else
+    #define AES_KEYLEN 16   // Key length in bytes
+    #define AES_keyExpSize 176
+#endif
+
+struct AES_ctx
+{
+  uint8_t RoundKey[AES_keyExpSize];
+#if (defined(CBC) && (CBC == 1)) || (defined(CTR) && (CTR == 1))
+  uint8_t Iv[AES_BLOCKLEN];
+#endif
+};
+
+void AES_init_ctx(struct AES_ctx* ctx, const uint8_t* key);
+#if (defined(CBC) && (CBC == 1)) || (defined(CTR) && (CTR == 1))
+void AES_init_ctx_iv(struct AES_ctx* ctx, const uint8_t* key, const uint8_t* iv);
+void AES_ctx_set_iv(struct AES_ctx* ctx, const uint8_t* iv);
+#endif
+
+#if defined(ECB) && (ECB == 1)
+// buffer size is exactly AES_BLOCKLEN bytes; 
+// you need only AES_init_ctx as IV is not used in ECB 
+// NB: ECB is considered insecure for most uses
+void AES_ECB_encrypt(const struct AES_ctx* ctx, uint8_t* buf);
+void AES_ECB_decrypt(const struct AES_ctx* ctx, uint8_t* buf);
+
+#endif // #if defined(ECB) && (ECB == !)
+
+
+#if defined(CBC) && (CBC == 1)
+// buffer size MUST be mutile of AES_BLOCKLEN;
+// Suggest https://en.wikipedia.org/wiki/Padding_(cryptography)#PKCS7 for padding scheme
+// NOTES: you need to set IV in ctx via AES_init_ctx_iv() or AES_ctx_set_iv()
+//        no IV should ever be reused with the same key 
+void AES_CBC_encrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, size_t length);
+void AES_CBC_decrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, size_t length);
+
+#endif // #if defined(CBC) && (CBC == 1)
+
+
+#if defined(CTR) && (CTR == 1)
+
+// Same function for encrypting as for decrypting. 
+// IV is incremented for every block, and used after encryption as XOR-compliment for output
+// Suggesting https://en.wikipedia.org/wiki/Padding_(cryptography)#PKCS7 for padding scheme
+// NOTES: you need to set IV in ctx with AES_init_ctx_iv() or AES_ctx_set_iv()
+//        no IV should ever be reused with the same key 
+void AES_CTR_xcrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, size_t length);
+
+#endif // #if defined(CTR) && (CTR == 1)
+
+
+#endif // _AES_H_
diff --git a/crypto/hmac.c b/crypto/hmac.c
new file mode 100644
index 0000000..f9b81c1
--- /dev/null
+++ b/crypto/hmac.c
@@ -0,0 +1,37 @@
+#include "hmac.h"
+
+/* function doing the HMAC-SHA-1 calculation */
+void hmac_sha1(const uint8_t* key, const uint32_t keysize, const uint8_t* msg, const uint32_t msgsize, uint8_t* output)
+{
+  struct sha1 outer, inner;
+  uint8_t tmp;
+
+  sha1_reset(&outer);
+  sha1_reset(&inner);
+
+  uint32_t i;
+  for (i = 0; i < keysize; ++i)
+  {
+    tmp = key[i] ^ 0x5C;
+    sha1_input(&outer, &tmp, 1);
+    tmp = key[i] ^ 0x36;
+    sha1_input(&inner, &tmp, 1);
+  }
+  for (; i < 64; ++i)
+  {
+    tmp = 0x5C;
+    sha1_input(&outer, &tmp, 1);
+    tmp = 0x36;
+    sha1_input(&inner, &tmp, 1);
+  }
+
+  sha1_input(&inner, msg, msgsize);
+  sha1_result(&inner, output);
+
+  sha1_input(&outer, output, HMAC_SHA1_HASH_SIZE);
+  sha1_result(&outer, output);
+}
+
+
+
+
diff --git a/crypto/hmac.h b/crypto/hmac.h
new file mode 100644
index 0000000..2c2d437
--- /dev/null
+++ b/crypto/hmac.h
@@ -0,0 +1,22 @@
+#ifndef __HMAC_H__
+#define __HMAC_H__
+
+#include <stdint.h>
+#include "sha1.h"
+
+#define HMAC_SHA1_HASH_SIZE 20
+
+/***********************************************************************'
+ * HMAC(K,m)      : HMAC SHA1
+ * @param key     : secret key
+ * @param keysize : key-length ín bytes
+ * @param msg     : msg to calculate HMAC over
+ * @param msgsize : msg-length in bytes
+ * @param output  : writeable buffer with at least 20 bytes available
+ */
+void hmac_sha1(const uint8_t* key, const uint32_t keysize, const uint8_t* msg, const uint32_t msgsize, uint8_t* output);
+
+
+#endif /* __HMAC_H__ */
+
+
diff --git a/crypto/pkcs7_padding.c b/crypto/pkcs7_padding.c
new file mode 100644
index 0000000..512f6b6
--- /dev/null
+++ b/crypto/pkcs7_padding.c
@@ -0,0 +1,56 @@
+#include "pkcs7_padding.h"
+
+int pkcs7_padding_pad_buffer( uint8_t *buffer,  size_t data_length, size_t buffer_size, uint8_t modulus ){
+  uint8_t pad_byte = modulus - ( data_length % modulus ) ;
+  if( data_length + pad_byte > buffer_size ){
+    return -pad_byte;
+  }
+  int i = 0;
+  while( i <  pad_byte){
+    buffer[data_length+i] = pad_byte;
+    i++;
+  }
+  return pad_byte;
+}
+
+int pkcs7_padding_valid( uint8_t *buffer, size_t data_length, size_t buffer_size, uint8_t modulus ){
+  uint8_t expected_pad_byte = modulus - ( data_length % modulus ) ;
+  if( data_length + expected_pad_byte > buffer_size ){
+    return 0;
+  }
+  int i = 0;
+  while( i < expected_pad_byte ){
+    if( buffer[data_length + i] != expected_pad_byte){
+      return 0;
+    }
+    i++;
+  }
+  return 1;
+}
+
+size_t pkcs7_padding_data_length( uint8_t * buffer, size_t buffer_size, uint8_t modulus ){
+  /* test for valid buffer size */
+  if( buffer_size % modulus != 0 ||
+    buffer_size < modulus ){
+    return 0;
+  }
+  uint8_t padding_value;
+  padding_value = buffer[buffer_size-1];
+  /* test for valid padding value */
+  if( padding_value < 1 || padding_value > modulus ){
+    return 0;
+  }
+  /* buffer must be at least padding_value + 1 in size */
+  if( buffer_size < padding_value + 1 ){
+    return 0;
+  }
+  uint8_t count = 1;
+  buffer_size --;
+  for( ; count  < padding_value ; count++){
+    buffer_size --;
+    if( buffer[buffer_size] != padding_value ){
+      return 0;
+    }
+  }
+  return buffer_size;
+}
\ No newline at end of file
diff --git a/crypto/pkcs7_padding.h b/crypto/pkcs7_padding.h
new file mode 100644
index 0000000..bdd6c21
--- /dev/null
+++ b/crypto/pkcs7_padding.h
@@ -0,0 +1,24 @@
+#ifndef _PKCS7_PADDING_H_
+#define _PKCS7_PADDING_H_
+
+#include <stdint.h>
+#include <stddef.h>
+
+/* Pad a buffer with bytes as defined in PKCS#7 
+ * Returns the number of pad bytes added, or zero if
+ * the buffer size is not large enough to hold the correctly padded data
+ */
+int pkcs7_padding_pad_buffer( uint8_t *buffer,  size_t data_length, size_t buffer_size, uint8_t modulus );
+
+int pkcs7_padding_valid( uint8_t *buffer, size_t data_length, size_t buffer_size, uint8_t modulus );
+
+/* Given a block of pkcs7 padded data, return the actual data length in the block based on the padding applied.
+ * buffer_size must be a multiple of modulus
+ * last byte 'x' in buffer must be between 1 and modulus
+ * buffer_size must be at least x + 1 in size
+ * last 'x' bytes in buffer must be same as 'x'
+ * returned size will be buffer_size - 'x'
+ */
+size_t pkcs7_padding_data_length( uint8_t * buffer, size_t buffer_size, uint8_t modulus );
+
+#endif
\ No newline at end of file
diff --git a/crypto/sha1.c b/crypto/sha1.c
new file mode 100644
index 0000000..ea2bf70
--- /dev/null
+++ b/crypto/sha1.c
@@ -0,0 +1,518 @@
+/*
+ *  sha1.c
+ *
+ *  Description:
+ *      This file implements the Secure Hashing Algorithm 1 as
+ *      defined in FIPS PUB 180-1 published April 17, 1995.
+ *
+ *      The SHA-1, produces a 160-bit message digest for a given
+ *      data stream.  It should take about 2**n steps to find a
+ *      message with the same digest as a given message and
+ *      2**(n/2) to find any two messages with the same digest,
+ *      when n is the digest size in bits.  Therefore, this
+ *      algorithm can serve as a means of providing a
+ *      "fingerprint" for a message.
+ *
+ * Caveats:
+ *     SHA-1 is designed to work with messages less than 2^64 bits
+ *     long.  Although SHA-1 allows a message digest to be generated
+ *     for messages of any number of bits less than 2^64, this
+ *     implementation only works with messages with a length that is
+ *     a multiple of the size of an 8-bit character.
+ *
+ */
+
+#include "sha1.h"
+
+/* Local Function Prototyptes */
+static void     _pad_block(struct sha1*);
+static void     _process_block(struct sha1*);
+
+/* SHA1 circular left shift */
+static uint32_t _circular_shift(const uint32_t nbits, const uint32_t word)
+{
+  return ((word << nbits) | (word >> (32 - nbits)));
+}
+
+/*
+ * sha1_reset
+ *
+ * Description:
+ *     This function will initialize the SHA1-context in preparation
+ *     for computing a new SHA1 message digest.
+ *
+ * Parameters:
+ *     context: [in/out]
+ *         The context to reset.
+ *
+ * Returns:
+ *     sha Error Code.
+ *
+ */
+int sha1_reset(struct sha1* context)
+{
+  if (context == 0)
+  {
+    return shaNull;
+  }
+
+  context->Length_Low           = 0;
+  context->Length_High          = 0;
+  context->Message_Block_Index  = 0;
+
+  context->Intermediate_Hash[0] = 0x67452301;
+  context->Intermediate_Hash[1] = 0xEFCDAB89;
+  context->Intermediate_Hash[2] = 0x98BADCFE;
+  context->Intermediate_Hash[3] = 0x10325476;
+  context->Intermediate_Hash[4] = 0xC3D2E1F0;
+
+  context->flags = 0;
+
+  return shaSuccess;
+}
+
+/*
+ * sha1_result
+ *
+ * Description:
+ *     This function will return the 160-bit message digest into the
+ *     Message_Digest array  provided by the caller.
+ *     NOTE: The first octet of hash is stored in the 0th element,
+ *           the last octet of hash in the 19th element.
+ *
+ * Parameters:
+ *     context: [in/out]
+ *         The context to use to calculate the SHA-1 hash.
+ *     Message_Digest: [out]
+ *         Where the digest is returned.
+ *
+ * Returns:
+ *     sha Error Code.
+ *
+ */
+int sha1_result(struct sha1* context, uint8_t Message_Digest[SHA1HashSize])
+{
+  int i;
+
+  if (    (context == 0)
+       || (Message_Digest == 0))
+  {
+    return shaNull;
+  }
+
+  if ((context->flags & FLAG_CORRUPTED) != 0)
+  {
+    return shaStateError;
+  }
+
+  if ((context->flags & FLAG_COMPUTED) == 0)
+  {
+    _pad_block(context);
+
+    for (i = 0; i < 64; ++i)
+    {
+      /* message may be sensitive, clear it out */
+      context->Message_Block[i] = 0;
+    }
+    context->Length_Low = 0;    /* and clear length */
+    context->Length_High = 0;
+    context->flags |= FLAG_COMPUTED;
+  }
+
+  for (i = 0; i < SHA1HashSize; ++i)
+  {
+    Message_Digest[i] = (context->Intermediate_Hash[i >> 2] >> (8 * (3 - (i & 0x03))));
+  }
+
+  return shaSuccess;
+}
+
+/*
+ *  sha1_input
+ *
+ *  Description:
+ *      This function accepts an array of octets as the next portion
+ *      of the message.
+ *
+ *  Parameters:
+ *      context: [in/out]
+ *          The SHA context to update
+ *      message_array: [in]
+ *          An array of characters representing the next portion of
+ *          the message.
+ *      length: [in]
+ *          The length of the message in message_array
+ *
+ *  Returns:
+ *      sha Error Code.
+ *
+ */
+int sha1_input(struct sha1* context, const uint8_t* message_array, unsigned length)
+{
+  if (length == 0)
+  {
+    return shaSuccess;
+  }
+
+  if (    (context == 0)
+       || (message_array == 0))
+  {
+    return shaNull;
+  }
+
+  if ((context->flags & FLAG_COMPUTED) != 0)
+  {
+    context->flags |= FLAG_CORRUPTED;
+    return shaStateError;
+  }
+
+  if ((context->flags & FLAG_CORRUPTED) != 0)
+  {
+    return shaStateError;
+  }
+
+  while (    (length != 0)
+          && (context->flags == 0))
+  {
+    context->Message_Block[context->Message_Block_Index] = (*message_array);
+
+    context->Message_Block_Index += 1;
+    context->Length_Low += 8;
+
+    if (context->Length_Low == 0)
+    {
+      context->Length_High += 1;
+
+      if (context->Length_High == 0)
+      {
+        /* Message is too long */
+        context->flags |= FLAG_CORRUPTED;
+      }
+    }
+
+    if (context->Message_Block_Index == 64)
+    {
+      _process_block(context);
+    }
+
+    message_array += 1;
+    length -= 1;
+  }
+
+  return shaSuccess;
+}
+
+/*
+ *  _process_block
+ *
+ *  Description:
+ *      This function will process the next 512 bits of the message
+ *      stored in the Message_Block array.
+ *
+ *  Parameters:
+ *      None.
+ *
+ *  Returns:
+ *      Nothing.
+ *
+ *  Comments:
+
+ *      Many of the variable names in this code, especially the
+ *      single character names, were used because those were the
+ *      names used in the publication.
+ *
+ *
+ */
+#if 0 // original code
+static void _process_block(struct sha1 *context)
+{
+  const uint32_t K[] = /* Constants defined in SHA-1 */
+  {
+    0x5A827999,
+    0x6ED9EBA1,
+    0x8F1BBCDC,
+    0xCA62C1D6
+  };
+  uint32_t t;                 /* Loop counter                */
+  uint32_t temp;              /* Temporary word value        */
+  uint32_t W[80];             /* Word sequence               */
+  uint32_t A, B, C, D, E;     /* Word buffers                */
+
+  /*
+   *  Initialize the first 16 words in the array W
+   */
+  for (t = 0; t < 16; ++t)
+  {
+    W[t]  = context->Message_Block[(t * 4) + 0] << 24;
+    W[t] |= context->Message_Block[(t * 4) + 1] << 16;
+    W[t] |= context->Message_Block[(t * 4) + 2] << 8;
+    W[t] |= context->Message_Block[(t * 4) + 3] << 0;
+  }
+
+  for (t = 16; t < 80; ++t)
+  {
+    W[t] = _circular_shift(1, W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16]);
+  }
+
+  A = context->Intermediate_Hash[0];
+  B = context->Intermediate_Hash[1];
+  C = context->Intermediate_Hash[2];
+  D = context->Intermediate_Hash[3];
+  E = context->Intermediate_Hash[4];
+
+  for (t = 0; t < 20; ++t)
+  {
+    temp =  _circular_shift(5, A) +
+            ((B & C) | ((~B) & D)) + E + W[t] + K[0];
+    E = D;
+    D = C;
+    C = _circular_shift(30, B);
+    B = A;
+    A = temp;
+  }
+
+  for (; t < 40; ++t)
+  {
+    temp = _circular_shift(5, A) + (B ^ C ^ D) + E + W[t] + K[1];
+    E = D;
+    D = C;
+    C = _circular_shift(30, B);
+    B = A;
+    A = temp;
+  }
+
+  for (; t < 60; ++t)
+  {
+    temp = _circular_shift(5, A) +
+           ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2];
+    E = D;
+    D = C;
+    C = _circular_shift(30, B);
+    B = A;
+    A = temp;
+  }
+
+  for (; t < 80; ++t)
+  {
+    temp = _circular_shift(5, A) + (B ^ C ^ D) + E + W[t] + K[3];
+    E = D;
+    D = C;
+    C = _circular_shift(30, B);
+    B = A;
+    A = temp;
+  }
+
+  context->Intermediate_Hash[0] += A;
+  context->Intermediate_Hash[1] += B;
+  context->Intermediate_Hash[2] += C;
+  context->Intermediate_Hash[3] += D;
+  context->Intermediate_Hash[4] += E;
+
+  context->Message_Block_Index = 0;
+}
+
+#else
+
+//#define METHOD2
+  void _process_block(struct sha1 *context)
+  {
+    const uint32_t K[] =             /* Constants defined in SHA-1 */
+    {
+      0x5A827999,
+      0x6ED9EBA1,
+      0x8F1BBCDC,
+      0xCA62C1D6
+    };
+    uint8_t       t;                 /* Loop counter                */
+    uint32_t      temp;              /* Temporary word value        */
+#ifdef METHOD2
+    uint8_t       s;
+    uint32_t      W[16];
+#else
+    uint32_t      W[80];             /* Word sequence               */
+#endif
+    uint32_t      A, B, C, D, E;     /* Word buffers                */
+
+   /*
+    * Initialize the first 16 words in the array W
+    */
+   for (t = 0; t < 16; ++t)
+   {
+      W[t]  = ((uint32_t)context->Message_Block[t * 4 + 0]) << 24;
+      W[t] |= ((uint32_t)context->Message_Block[t * 4 + 1]) << 16;
+      W[t] |= ((uint32_t)context->Message_Block[t * 4 + 2]) << 8;
+      W[t] |= ((uint32_t)context->Message_Block[t * 4 + 3]) << 0;
+    }
+
+#ifndef METHOD2
+    for (t = 16; t < 80; ++t)
+    {
+      W[t] = _circular_shift(1, (W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16]));
+    }
+#endif
+
+    A = context->Intermediate_Hash[0];
+    B = context->Intermediate_Hash[1];
+    C = context->Intermediate_Hash[2];
+    D = context->Intermediate_Hash[3];
+    E = context->Intermediate_Hash[4];
+
+    for (t = 0; t < 20; ++t)
+    {
+#ifdef METHOD2
+      s = t & 0x0f;
+      if (t >= 16)
+      {
+	W[s] = _circular_shift(1, (W[(s + 13) & 0x0f] ^ W[(s + 8) & 0x0f] ^ W[(s + 2) & 0x0f] ^ W[s]));
+      }
+      temp =  _circular_shift(5, A) + ((B & C) | ((~B) & D)) + E + W[s] + K[0];
+#else
+      temp =  _circular_shift(5, A) + ((B & C) | ((~B) & D)) + E + W[t] + K[0];
+#endif
+      E = D;
+      D = C;
+      C = _circular_shift(30, B);
+      B = A;
+      A = temp;
+    }
+
+    for (t = 20; t < 40; ++t)
+    {
+#ifdef METHOD2
+      s = (t & 0x0f);
+      W[s] = _circular_shift(1, (W[(s + 13) & 0x0f] ^ W[(s + 8) & 0x0f] ^ W[(s + 2) & 0x0f] ^ W[s]));
+      temp = _circular_shift(5, A) + (B ^ C ^ D) + E + W[s] + K[1];
+#else
+      temp = _circular_shift(5, A) + (B ^ C ^ D) + E + W[t] + K[1];
+#endif
+      E = D;
+      D = C;
+      C = _circular_shift(30, B);
+      B = A;
+      A = temp;
+    }
+
+    for (t = 40; t < 60; ++t)
+    {
+#ifdef METHOD2
+      s = (t & 0x0f);
+      W[s] = _circular_shift(1, (W[(s + 13) & 0x0f] ^ W[(s + 8) & 0x0f] ^ W[(s + 2) & 0x0f] ^ W[s]));
+      temp = _circular_shift(5, A) + ((B & C) | (B & D) | (C & D)) + E + W[s] + K[2];
+#else
+      temp = _circular_shift(5, A) + ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2];
+#endif
+      E = D;
+      D = C;
+      C = _circular_shift(30, B);
+      B = A;
+      A = temp;
+    }
+
+    for (t = 60; t < 80; ++t)
+    {
+#ifdef METHOD2
+      s = (t & 0x0f);
+      W[s] = _circular_shift(1, (W[(s + 13) & 0x0f] ^ W[(s + 8) & 0x0f] ^ W[(s + 2) & 0x0f] ^ W[s]));
+      temp = _circular_shift(5, A) + (B ^ C ^ D) + E + W[s] + K[3];
+#else
+      temp = _circular_shift(5, A) + (B ^ C ^ D) + E + W[t] + K[3];
+#endif
+      E = D;
+      D = C;
+      C = _circular_shift(30, B);
+      B = A;
+      A = temp;
+    }
+
+    context->Intermediate_Hash[0] += A;
+    context->Intermediate_Hash[1] += B;
+    context->Intermediate_Hash[2] += C;
+    context->Intermediate_Hash[3] += D;
+    context->Intermediate_Hash[4] += E;
+
+    context->Message_Block_Index = 0;
+  }
+
+#endif
+
+
+/*
+ *  _pad_block
+ *
+ * Description:
+ *     According to the standard, the message must be padded to an even
+ *     512 bits.  The first padding bit must be a '1'.  The last 64
+ *     bits represent the length of the original message.  All bits in
+ *     between should be 0.  This function will pad the message
+ *     according to those rules by filling the Message_Block array
+ *     accordingly.  It will also call the ProcessMessageBlock function
+ *     provided appropriately.  When it returns, it can be assumed that
+ *     the message digest has been computed.
+ *
+ * Parameters:
+ *     context: [in/out]
+ *         The context to pad
+ *     ProcessMessageBlock: [in]
+ *         The appropriate SHA*ProcessMessageBlock function
+ * Returns:
+ *     Nothing.
+ *
+ */
+static void _pad_block(struct sha1* context)
+{
+  /*
+   * Check to see if the current message block is too small to hold
+   * the initial padding bits and length.  If so, we will pad the
+   * block, process it, and then continue padding into a second
+   * block.
+   */
+  if (context->Message_Block_Index > 55)
+  {
+    context->Message_Block[context->Message_Block_Index] = 0x80;
+    context->Message_Block_Index += 1;
+
+    while (context->Message_Block_Index < 64)
+    {
+      context->Message_Block[context->Message_Block_Index] = 0;
+      context->Message_Block_Index += 1;
+    }
+
+    _process_block(context);
+
+    while (context->Message_Block_Index < 56)
+    {
+      context->Message_Block[context->Message_Block_Index] = 0;
+      context->Message_Block_Index += 1;
+    }
+  }
+  else
+  {
+    context->Message_Block[context->Message_Block_Index] = 0x80;
+    context->Message_Block_Index += 1;
+
+    while (context->Message_Block_Index < 56)
+    {
+      context->Message_Block[context->Message_Block_Index] = 0;
+      context->Message_Block_Index += 1;
+    }
+  }
+
+  /*
+   * Store the message length as the last 8 bytes
+   */
+  context->Message_Block[56] = context->Length_High >> 24;
+  context->Message_Block[57] = context->Length_High >> 16;
+  context->Message_Block[58] = context->Length_High >>  8;
+  context->Message_Block[59] = context->Length_High >>  0;
+  context->Message_Block[60] = context->Length_Low  >> 24;
+  context->Message_Block[61] = context->Length_Low  >> 16;
+  context->Message_Block[62] = context->Length_Low  >>  8;
+  context->Message_Block[63] = context->Length_Low  >>  0;
+
+  _process_block(context);
+}
+
+
+
+
+
diff --git a/crypto/sha1.h b/crypto/sha1.h
new file mode 100644
index 0000000..58817ce
--- /dev/null
+++ b/crypto/sha1.h
@@ -0,0 +1,61 @@
+/*
+ *  sha1.h
+ *
+ *  Description:
+ *      This is the header file for code which implements the Secure
+ *      Hashing Algorithm 1 as defined in FIPS PUB 180-1 published
+ *      April 17, 1995.
+ *
+ *      Many of the variable names in this code, especially the
+ *      single character names, were used because those were the names
+ *      used in the publication.
+ *
+ *      Please read the file sha1.c for more information.
+ *
+ */
+
+#ifndef _SHA1_H_
+#define _SHA1_H_
+
+#include <stdint.h>
+
+#define SHA1HashSize 20
+
+enum
+{
+  shaSuccess = 0,
+  shaNull,            /* Null pointer parameter */
+  shaInputTooLong,    /* input data too long */
+  shaStateError       /* called Input after Result */
+};
+
+#define FLAG_COMPUTED   1
+#define FLAG_CORRUPTED  2
+
+/*
+ * Data structure holding contextual information about the SHA-1 hash
+ */
+struct sha1
+{
+  uint8_t  Message_Block[64];       /* 512-bit message blocks         */
+  uint32_t Intermediate_Hash[5];    /* Message Digest                 */
+  uint32_t Length_Low;              /* Message length in bits         */
+  uint32_t Length_High;             /* Message length in bits         */
+  uint16_t Message_Block_Index;     /* Index into message block array */
+  uint8_t  flags;
+};
+
+
+
+/* 
+ * Public API
+ */
+int sha1_reset (struct sha1* context);
+int sha1_input (struct sha1* context, const uint8_t* message_array, unsigned length);
+int sha1_result(struct sha1* context, uint8_t Message_Digest[SHA1HashSize]);
+
+
+
+#endif /* #ifndef _SHA1_H_ */
+
+
diff --git a/crypto/update.sh b/crypto/update.sh
new file mode 100755
index 0000000..c9cd37a
--- /dev/null
+++ b/crypto/update.sh
@@ -0,0 +1,14 @@
+#!/usr/bin/env sh
+
+set -e
+set -x
+
+MYDIR="$(dirname ${0})"
+wget 'https://raw.githubusercontent.com/kokke/tiny-AES-c/master/aes.c' -O "${MYDIR}/aes.c"
+wget 'https://raw.githubusercontent.com/kokke/tiny-AES-c/master/aes.h' -O "${MYDIR}/aes.h"
+wget 'https://raw.githubusercontent.com/kokke/tiny-HMAC-c/main/src/hmac.c' -O "${MYDIR}/hmac.c"
+wget 'https://raw.githubusercontent.com/kokke/tiny-HMAC-c/main/src/hmac.h' -O "${MYDIR}/hmac.h"
+wget 'https://raw.githubusercontent.com/kokke/tiny-HMAC-c/main/src/sha1.c' -O "${MYDIR}/sha1.c"
+wget 'https://raw.githubusercontent.com/kokke/tiny-HMAC-c/main/src/sha1.h' -O "${MYDIR}/sha1.h"
+wget 'https://raw.githubusercontent.com/bonybrown/tiny-AES128-C/master/pkcs7_padding.c' -O "${MYDIR}/pkcs7_padding.c"
+wget 'https://raw.githubusercontent.com/bonybrown/tiny-AES128-C/master/pkcs7_padding.h' -O "${MYDIR}/pkcs7_padding.h"