--- /dev/null
+/*
+ * 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.
+ *
+ * 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
+ * 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.
+ *
+ */
+
+
+
+#include "sha1.h"
+
+/*
+ * Define the SHA1 circular left shift macro
+ */
+#define SHA1CircularShift(bits,word) \
+ (((word) << (bits)) | ((word) >> (32-(bits))))
+
+/* Local Function Prototyptes */
+void SHA1PadMessage(SHA1Context *);
+void SHA1ProcessMessageBlock(SHA1Context *);
+
+/*
+ * SHA1Reset
+ *
+ * Description:
+ * This function will initialize the SHA1Context in preparation
+ * for computing a new SHA1 message digest.
+ *
+ * Parameters:
+ * context: [in/out]
+ * The context to reset.
+ *
+ * Returns:
+ * sha Error Code.
+ *
+ */
+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;
+}
+
+/*
+ * 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;
+}
+
+/*
+ * SHA1Input
+ *
+ * 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 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) {
+ 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++;
+ }
+
+ return shaSuccess;
+}
+
+/*
+ * SHA1ProcessMessageBlock
+ *
+ * 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.
+ *
+ *
+ */
+void SHA1ProcessMessageBlock(SHA1Context * context)
+{
+ 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;
+}
+
+
+/*
+ * SHA1PadMessage
+ *
+ * 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.
+ *
+ */
+
+void SHA1PadMessage(SHA1Context * 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;
+ 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;
+
+ SHA1ProcessMessageBlock(context);
+}
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