1sha(3)                              OpenSSL                             sha(3)
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NAME

6       SHA1, SHA1_Init, SHA1_Update, SHA1_Final - Secure Hash Algorithm
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SYNOPSIS

9        #include <openssl/sha.h>
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11        unsigned char *SHA1(const unsigned char *d, unsigned long n,
12                         unsigned char *md);
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14        void SHA1_Init(SHA_CTX *c);
15        void SHA1_Update(SHA_CTX *c, const void *data,
16                         unsigned long len);
17        void SHA1_Final(unsigned char *md, SHA_CTX *c);
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DESCRIPTION

20       SHA-1 (Secure Hash Algorithm) is a cryptographic hash function with a
21       160 bit output.
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23       SHA1() computes the SHA-1 message digest of the n bytes at d and places
24       it in md (which must have space for SHA_DIGEST_LENGTH == 20 bytes of
25       output). If md is NULL, the digest is placed in a static array.
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27       The following functions may be used if the message is not completely
28       stored in memory:
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30       SHA1_Init() initializes a SHA_CTX structure.
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32       SHA1_Update() can be called repeatedly with chunks of the message to be
33       hashed (len bytes at data).
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35       SHA1_Final() places the message digest in md, which must have space for
36       SHA_DIGEST_LENGTH == 20 bytes of output, and erases the SHA_CTX.
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38       Applications should use the higher level functions EVP_DigestInit(3)
39       etc. instead of calling the hash functions directly.
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41       The predecessor of SHA-1, SHA, is also implemented, but it should be
42       used only when backward compatibility is required.
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RETURN VALUES

45       SHA1() returns a pointer to the hash value.
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47       SHA1_Init(), SHA1_Update() and SHA1_Final() do not return values.
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CONFORMING TO

50       SHA: US Federal Information Processing Standard FIPS PUB 180 (Secure
51       Hash Standard), SHA-1: US Federal Information Processing Standard FIPS
52       PUB 180-1 (Secure Hash Standard), ANSI X9.30
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SEE ALSO

55       ripemd(3), hmac(3), EVP_DigestInit(3)
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HISTORY

58       SHA1(), SHA1_Init(), SHA1_Update() and SHA1_Final() are available in
59       all versions of SSLeay and OpenSSL.
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630.9.8b                            2000-02-25                            sha(3)