Replace SHA1 implementation with the one from RFC 6234.

1 files changed, 328 insertions, 325 deletions

diff --git a/common/sha1.c b/common/sha1.c
index 988b188..53f1872 100644
--- a/common/sha1.c
+++ b/common/sha1.c
@@ -1,73 +1,66 @@
-/*
- * Copyright (C) The Internet Society (2001).  All Rights Reserved.
- *
- * This document and translations of it may be copied and furnished to
- * others, and derivative works that comment on or otherwise explain it
- * or assist in its implementation may be prepared, copied, published
- * and distributed, in whole or in part, without restriction of any
- * kind, provided that the above copyright notice and this paragraph are
- * included on all such copies and derivative works.  However, this
- * document itself may not be modified in any way, such as by removing
- * the copyright notice or references to the Internet Society or other
- * Internet organizations, except as needed for the purpose of
- * developing Internet standards in which case the procedures for
- * copyrights defined in the Internet Standards process must be
- * followed, or as required to translate it into languages other than
- * English.
- *
- * The limited permissions granted above are perpetual and will not be
- * revoked by the Internet Society or its successors or assigns.
- *
- * This document and the information contained herein is provided on an
- * "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
- * TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
- * BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
- * HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
- * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
- */
+/**************************** sha1.c ***************************/
+/***************** See RFC 6234 for details. *******************/
+/* Copyright (c) 2011 IETF Trust and the persons identified as */
+/* authors of the code.  All rights reserved.                  */
+/* See sha.h for terms of use and redistribution.              */
 
 /*
- *  sha1.c
- *
  *  Description:
- *      This file implements the Secure Hashing Algorithm 1 as
- *      defined in FIPS PUB 180-1 published April 17, 1995.
+ *      This file implements the Secure Hash Algorithm SHA-1
+ *      as defined in the U.S. National Institute of Standards
+ *      and Technology Federal Information Processing Standards
+ *      Publication (FIPS PUB) 180-3 published in October 2008
+ *      and formerly defined in its predecessors, FIPS PUB 180-1
+ *      and FIP PUB 180-2.
  *
- *      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
+ *      A combined document showing all algorithms is available at
+ *              http://csrc.nist.gov/publications/fips/
+ *                     fips180-3/fips180-3_final.pdf
+ *
+ *      The SHA-1 algorithm produces a 160-bit message digest for a
+ *      given data stream that can serve as a means of providing a
  *      "fingerprint" for a message.
  *
  *  Portability Issues:
  *      SHA-1 is defined in terms of 32-bit "words".  This code
- *      uses <stdint.h> (included via "sha1.h" to define 32 and 8
- *      bit unsigned integer types.  If your C compiler does not
- *      support 32 bit unsigned integers, this code is not
+ *      uses <stdint.h> (included via "sha.h") to define 32- and
+ *      8-bit unsigned integer types.  If your C compiler does
+ *      not support 32-bit unsigned integers, this code is not
  *      appropriate.
  *
  *  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.
- *
+ *      long.  This implementation uses SHA1Input() to hash the bits
+ *      that are a multiple of the size of an 8-bit octet, and then
+ *      optionally uses SHA1FinalBits() to hash the final few bits of
+ *      the input.
  */
 
-#include "sha1.h"
+#include "sha.h"
+#include "sha-private.h"
 
 /*
  *  Define the SHA1 circular left shift macro
  */
-#define SHA1CircularShift(bits,word) \
+#define SHA1_ROTL(bits,word) \
                 (((word) << (bits)) | ((word) >> (32-(bits))))
 
-/* Local Function Prototyptes */
-void SHA1PadMessage(SHA1Context *);
-void SHA1ProcessMessageBlock(SHA1Context *);
+/*
+ * Add "length" to the length.
+ * Set Corrupted when overflow has occurred.
+ */
+static uint32_t addTemp;
+#define SHA1AddLength(context, length)                     \
+    (addTemp = (context)->Length_Low,                      \
+     (context)->Corrupted =                                \
+        (((context)->Length_Low += (length)) < addTemp) && \
+        (++(context)->Length_High == 0) ? shaInputTooLong  \
+                                        : (context)->Corrupted )
+
+/* Local Function Prototypes */
+static void SHA1ProcessMessageBlock(SHA1Context *context);
+static void SHA1Finalize(SHA1Context *context, uint8_t Pad_Byte);
+static void SHA1PadMessage(SHA1Context *context, uint8_t Pad_Byte);
 
 /*
  *  SHA1Reset
@@ -86,80 +79,22 @@ void SHA1ProcessMessageBlock(SHA1Context *);
  */
 int SHA1Reset(SHA1Context *context)
 {
-    if (!context)
-    {
-        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->Computed   = 0;
-    context->Corrupted  = 0;
-    return shaSuccess;
-}
+  if (!context) return shaNull;
 
-/*
- *  SHA1Result
- *
- *  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 SHA1Result( SHA1Context *context,
-                uint8_t Message_Digest[SHA1HashSize])
-{
-    int i;
-
-    if (!context || !Message_Digest)
-    {
-        return shaNull;
-    }
-
-    if (context->Corrupted)
-    {
-        return context->Corrupted;
-    }
-
-    if (!context->Computed)
-    {
-        SHA1PadMessage(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->Computed = 1;
-    }
-
-    for(i = 0; i < SHA1HashSize; ++i)
-    {
-        Message_Digest[i] = context->Intermediate_Hash[i>>2]
-                            >> 8 * ( 3 - ( i & 0x03 ) );
-    }
-
-    return shaSuccess;
+  context->Length_High = context->Length_Low = 0;
+  context->Message_Block_Index = 0;
+
+  /* Initial Hash Values: FIPS 180-3 section 5.3.1 */
+  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->Computed   = 0;
+  context->Corrupted  = shaSuccess;
+
+  return shaSuccess;
 }
 
 /*
@@ -171,241 +106,309 @@ int SHA1Result( SHA1Context *context,
  *
  *  Parameters:
  *      context: [in/out]
- *          The SHA context to update
- *      message_array: [in]
- *          An array of characters representing the next portion of
+ *          The SHA context to update.
+ *      message_array[ ]: [in]
+ *          An array of octets representing the next portion of
  *          the message.
  *      length: [in]
- *          The length of the message in message_array
+ *          The length of the message in message_array.
  *
  *  Returns:
  *      sha Error Code.
  *
  */
-int SHA1Input(    SHA1Context    *context,
-                  const uint8_t  *message_array,
-                  unsigned       length)
+int SHA1Input(SHA1Context *context,
+    const uint8_t *message_array, unsigned length)
 {
-    if (!length)
-    {
-        return shaSuccess;
-    }
-
-    if (!context || !message_array)
-    {
-        return shaNull;
-    }
-
-    if (context->Computed)
-    {
-        context->Corrupted = shaStateError;
-        return shaStateError;
-    }
-
-    if (context->Corrupted)
-    {
-         return context->Corrupted;
-    }
-    while(length-- && !context->Corrupted)
-    {
+  if (!context) return shaNull;
+  if (!length) return shaSuccess;
+  if (!message_array) return shaNull;
+  if (context->Computed) return context->Corrupted = shaStateError;
+  if (context->Corrupted) return context->Corrupted;
+
+  while (length--) {
     context->Message_Block[context->Message_Block_Index++] =
-                    (*message_array & 0xFF);
-
-    context->Length_Low += 8;
-    if (context->Length_Low == 0)
-    {
-        context->Length_High++;
-        if (context->Length_High == 0)
-        {
-            /* Message is too long */
-            context->Corrupted = 1;
-        }
-    }
-
-    if (context->Message_Block_Index == 64)
-    {
-        SHA1ProcessMessageBlock(context);
-    }
+      *message_array;
+
+    if ((SHA1AddLength(context, 8) == shaSuccess) &&
+      (context->Message_Block_Index == SHA1_Message_Block_Size))
+      SHA1ProcessMessageBlock(context);
 
     message_array++;
-    }
+  }
 
-    return shaSuccess;
+  return context->Corrupted;
 }
 
 /*
- *  SHA1ProcessMessageBlock
+ * SHA1FinalBits
  *
- *  Description:
- *      This function will process the next 512 bits of the message
- *      stored in the Message_Block array.
+ * Description:
+ *   This function will add in any final bits of the message.
  *
- *  Parameters:
- *      None.
+ * Parameters:
+ *   context: [in/out]
+ *     The SHA context to update.
+ *   message_bits: [in]
+ *     The final bits of the message, in the upper portion of the
+ *     byte.  (Use 0b###00000 instead of 0b00000### to input the
+ *     three bits ###.)
+ *   length: [in]
+ *     The number of bits in message_bits, between 1 and 7.
  *
- *  Returns:
- *      Nothing.
+ * Returns:
+ *   sha Error Code.
+ */
+int SHA1FinalBits(SHA1Context *context, uint8_t message_bits,
+    unsigned int length)
+{
+  static uint8_t masks[8] = {
+      /* 0 0b00000000 */ 0x00, /* 1 0b10000000 */ 0x80,
+      /* 2 0b11000000 */ 0xC0, /* 3 0b11100000 */ 0xE0,
+      /* 4 0b11110000 */ 0xF0, /* 5 0b11111000 */ 0xF8,
+      /* 6 0b11111100 */ 0xFC, /* 7 0b11111110 */ 0xFE
+  };
+
+  static uint8_t markbit[8] = {
+      /* 0 0b10000000 */ 0x80, /* 1 0b01000000 */ 0x40,
+      /* 2 0b00100000 */ 0x20, /* 3 0b00010000 */ 0x10,
+      /* 4 0b00001000 */ 0x08, /* 5 0b00000100 */ 0x04,
+      /* 6 0b00000010 */ 0x02, /* 7 0b00000001 */ 0x01
+  };
+
+  if (!context) return shaNull;
+  if (!length) return shaSuccess;
+  if (context->Corrupted) return context->Corrupted;
+  if (context->Computed) return context->Corrupted = shaStateError;
+  if (length >= 8) return context->Corrupted = shaBadParam;
+
+  SHA1AddLength(context, length);
+  SHA1Finalize(context,
+    (uint8_t) ((message_bits & masks[length]) | markbit[length]));
+
+  return context->Corrupted;
+}
+
+/*
+ * SHA1Result
+ *
+ * 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 element with index 0,
+ *      the last octet of hash in the element with index 19.
  *
- *  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.
+ * 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.
  *
  */
-void SHA1ProcessMessageBlock(SHA1Context *context)
+int SHA1Result(SHA1Context *context,
+    uint8_t Message_Digest[SHA1HashSize])
 {
-    const uint32_t K[] =    {       /* Constants defined in SHA-1   */
-                            0x5A827999,
-                            0x6ED9EBA1,
-                            0x8F1BBCDC,
-                            0xCA62C1D6
-                            };
-    int           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] << 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];
-    }
-
-    for(t = 16; t < 80; t++)
-    {
-       W[t] = SHA1CircularShift(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 =  SHA1CircularShift(5,A) +
-                ((B & C) | ((~B) & D)) + E + W[t] + K[0];
-        E = D;
-        D = C;
-        C = SHA1CircularShift(30,B);
-        B = A;
-        A = temp;
-    }
-
-    for(t = 20; t < 40; t++)
-    {
-        temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[1];
-        E = D;
-        D = C;
-        C = SHA1CircularShift(30,B);
-        B = A;
-        A = temp;
-    }
-
-    for(t = 40; t < 60; t++)
-    {
-        temp = SHA1CircularShift(5,A) +
-               ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2];
-        E = D;
-        D = C;
-        C = SHA1CircularShift(30,B);
-        B = A;
-        A = temp;
-    }
-
-    for(t = 60; t < 80; t++)
-    {
-        temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[3];
-        E = D;
-        D = C;
-        C = SHA1CircularShift(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;
+  int i;
+
+  if (!context) return shaNull;
+  if (!Message_Digest) return shaNull;
+  if (context->Corrupted) return context->Corrupted;
+
+  if (!context->Computed)
+    SHA1Finalize(context, 0x80);
+
+  for (i = 0; i < SHA1HashSize; ++i)
+    Message_Digest[i] = (uint8_t) (context->Intermediate_Hash[i>>2]
+                                   >> (8 * ( 3 - ( i & 0x03 ) )));
+
+  return shaSuccess;
 }
 
+/*
+ * SHA1ProcessMessageBlock
+ *
+ * Description:
+ *   This helper function will process the next 512 bits of the
+ *   message stored in the Message_Block array.
+ *
+ * Parameters:
+ *   context: [in/out]
+ *     The SHA context to update.
+ *
+ * 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 Secure Hash Standard.
+ */
+static void SHA1ProcessMessageBlock(SHA1Context *context)
+{
+  /* Constants defined in FIPS 180-3, section 4.2.1 */
+  const uint32_t K[4] = {
+      0x5A827999, 0x6ED9EBA1, 0x8F1BBCDC, 0xCA62C1D6
+  };
+
+  int        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]  = ((uint32_t)context->Message_Block[t * 4]) << 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]);
+  }
+
+  for (t = 16; t < 80; t++)
+    W[t] = SHA1_ROTL(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 = SHA1_ROTL(5,A) + SHA_Ch(B, C, D) + E + W[t] + K[0];
+    E = D;
+    D = C;
+    C = SHA1_ROTL(30,B);
+    B = A;
+    A = temp;
+  }
+
+  for (t = 20; t < 40; t++) {
+    temp = SHA1_ROTL(5,A) + SHA_Parity(B, C, D) + E + W[t] + K[1];
+    E = D;
+    D = C;
+    C = SHA1_ROTL(30,B);
+    B = A;
+    A = temp;
+  }
+
+  for (t = 40; t < 60; t++) {
+    temp = SHA1_ROTL(5,A) + SHA_Maj(B, C, D) + E + W[t] + K[2];
+    E = D;
+    D = C;
+    C = SHA1_ROTL(30,B);
+    B = A;
+    A = temp;
+  }
+
+  for (t = 60; t < 80; t++) {
+    temp = SHA1_ROTL(5,A) + SHA_Parity(B, C, D) + E + W[t] + K[3];
+    E = D;
+    D = C;
+    C = SHA1_ROTL(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;
+}
 
 /*
- *  SHA1PadMessage
+ * SHA1Finalize
  *
- *  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.
+ * Description:
+ *   This helper function finishes off the digest calculations.
  *
- *  Parameters:
- *      context: [in/out]
- *          The context to pad
- *      ProcessMessageBlock: [in]
- *          The appropriate SHA*ProcessMessageBlock function
- *  Returns:
- *      Nothing.
+ * Parameters:
+ *   context: [in/out]
+ *     The SHA context to update.
+ *   Pad_Byte: [in]
+ *     The last byte to add to the message block before the 0-padding
+ *     and length.  This will contain the last bits of the message
+ *     followed by another single bit.  If the message was an
+ *     exact multiple of 8-bits long, Pad_Byte will be 0x80.
+ *
+ * Returns:
+ *   sha Error Code.
  *
  */
+static void SHA1Finalize(SHA1Context *context, uint8_t Pad_Byte)
+{
+  int i;
+  SHA1PadMessage(context, Pad_Byte);
+  /* message may be sensitive, clear it out */
+  for (i = 0; i < SHA1_Message_Block_Size; ++i)
+    context->Message_Block[i] = 0;
+  context->Length_High = 0;     /* and clear length */
+  context->Length_Low = 0;
+  context->Computed = 1;
+}
 
-void SHA1PadMessage(SHA1Context *context)
+/*
+ * SHA1PadMessage
+ *
+ * Description:
+ *   According to the standard, the message must be padded to the next
+ *   even multiple of 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 helper function will pad
+ *   the message according to those rules by filling the Message_Block
+ *   array accordingly.  When it returns, it can be assumed that the
+ *   message digest has been computed.
+ *
+ * Parameters:
+ *   context: [in/out]
+ *     The context to pad.
+ *   Pad_Byte: [in]
+ *     The last byte to add to the message block before the 0-padding
+ *     and length.  This will contain the last bits of the message
+ *     followed by another single bit.  If the message was an
+ *     exact multiple of 8-bits long, Pad_Byte will be 0x80.
+ *
+ * Returns:
+ *   Nothing.
+ */
+static void SHA1PadMessage(SHA1Context *context, uint8_t Pad_Byte)
 {
-    /*
-     *  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;
-        while(context->Message_Block_Index < 64)
-        {
-            context->Message_Block[context->Message_Block_Index++] = 0;
-        }
-
-        SHA1ProcessMessageBlock(context);
-
-        while(context->Message_Block_Index < 56)
-        {
-            context->Message_Block[context->Message_Block_Index++] = 0;
-        }
-    }
-    else
-    {
-        context->Message_Block[context->Message_Block_Index++] = 0x80;
-        while(context->Message_Block_Index < 56)
-        {
-            context->Message_Block[context->Message_Block_Index++] = 0;
-        }
-    }
-
-    /*
-     *  Store the message length as the last 8 octets
-     */
-    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;
-    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;
+  /*
+   * 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 >= (SHA1_Message_Block_Size - 8)) {
+    context->Message_Block[context->Message_Block_Index++] = Pad_Byte;
+    while (context->Message_Block_Index < SHA1_Message_Block_Size)
+      context->Message_Block[context->Message_Block_Index++] = 0;
 
     SHA1ProcessMessageBlock(context);
+  } else
+    context->Message_Block[context->Message_Block_Index++] = Pad_Byte;
+
+  while (context->Message_Block_Index < (SHA1_Message_Block_Size - 8))
+    context->Message_Block[context->Message_Block_Index++] = 0;
+
+  /*
+   * Store the message length as the last 8 octets
+   */
+  context->Message_Block[56] = (uint8_t) (context->Length_High >> 24);
+  context->Message_Block[57] = (uint8_t) (context->Length_High >> 16);
+  context->Message_Block[58] = (uint8_t) (context->Length_High >> 8);
+  context->Message_Block[59] = (uint8_t) (context->Length_High);
+  context->Message_Block[60] = (uint8_t) (context->Length_Low >> 24);
+  context->Message_Block[61] = (uint8_t) (context->Length_Low >> 16);
+  context->Message_Block[62] = (uint8_t) (context->Length_Low >> 8);
+  context->Message_Block[63] = (uint8_t) (context->Length_Low);
+
+  SHA1ProcessMessageBlock(context);
 }
+