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Annotation of src/include/sha1.h, Revision 1.1

1.1     ! millert     1: /* --------------------------------- SHA1.H ------------------------------- */
        !             2:
        !             3: /* NIST proposed Secure Hash Standard.
        !             4:
        !             5:    Written 2 September 1992, Peter C. Gutmann.
        !             6:    This implementation placed in the public domain.
        !             7:
        !             8:    Comments to pgut1@cs.aukuni.ac.nz */
        !             9:
        !            10: /* Useful defines/typedefs */
        !            11:
        !            12: typedef unsigned char   BYTE;
        !            13: typedef u_int32_t      LONG;
        !            14:
        !            15: /* The SHA1 block size and message digest sizes, in bytes */
        !            16:
        !            17: #define SHA1_BLOCKSIZE   64
        !            18: #define SHA1_DIGESTSIZE  20
        !            19:
        !            20: /* The structure for storing SHA1 info */
        !            21:
        !            22: typedef struct {
        !            23:               LONG digest[ 5 ];            /* Message digest */
        !            24:               LONG countLo, countHi;       /* 64-bit bit count */
        !            25:               LONG data[ 16 ];             /* SHA1 data buffer */
        !            26:               } SHA1_INFO;
        !            27:
        !            28: /* The next def turns on the change to the algorithm introduced by NIST at
        !            29:  * the behest of the NSA.  It supposedly corrects a weakness in the original
        !            30:  * formulation.  Bruce Schneier described it thus in a posting to the
        !            31:  * Cypherpunks mailing list on June 21, 1994 (as told to us by Steve Bellovin):
        !            32:  *
        !            33:  *     This is the fix to the Secure Hash Standard, NIST FIPS PUB 180:
        !            34:  *
        !            35:  *          In Section 7 of FIPS 180 (page 9), the line which reads
        !            36:  *
        !            37:  *          "b) For t=16 to 79 let Wt = Wt-3 XOR Wt-8 XOR Wt-14 XOR
        !            38:  *          Wt-16."
        !            39:  *
        !            40:  *          is to be replaced by
        !            41:  *
        !            42:  *          "b) For t=16 to 79 let Wt = S1(Wt-3 XOR Wt-8 XOR Wt-14 XOR
        !            43:  *          Wt-16)."
        !            44:  *
        !            45:  *          where S1 is a left circular shift by one bit as defined in
        !            46:  *          Section 3 of FIPS 180 (page 6):
        !            47:  *
        !            48:  *          S1(X) = (X<<1) OR (X>>31).
        !            49:  *
        !            50:  */
        !            51:
        !            52: #define NEW_SHA1