1SHA256_INIT(3ossl)                  OpenSSL                 SHA256_INIT(3ossl)
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NAME

6       SHA1, SHA1_Init, SHA1_Update, SHA1_Final, SHA224, SHA224_Init,
7       SHA224_Update, SHA224_Final, SHA256, SHA256_Init, SHA256_Update,
8       SHA256_Final, SHA384, SHA384_Init, SHA384_Update, SHA384_Final, SHA512,
9       SHA512_Init, SHA512_Update, SHA512_Final - Secure Hash Algorithm
10

SYNOPSIS

12        #include <openssl/sha.h>
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14        unsigned char *SHA1(const unsigned char *data, size_t count, unsigned char *md_buf);
15        unsigned char *SHA224(const unsigned char *data, size_t count, unsigned char *md_buf);
16        unsigned char *SHA256(const unsigned char *data, size_t count, unsigned char *md_buf);
17        unsigned char *SHA384(const unsigned char *data, size_t count, unsigned char *md_buf);
18        unsigned char *SHA512(const unsigned char *data, size_t count, unsigned char *md_buf);
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20       The following functions have been deprecated since OpenSSL 3.0, and can
21       be hidden entirely by defining OPENSSL_API_COMPAT with a suitable
22       version value, see openssl_user_macros(7):
23
24        int SHA1_Init(SHA_CTX *c);
25        int SHA1_Update(SHA_CTX *c, const void *data, size_t len);
26        int SHA1_Final(unsigned char *md, SHA_CTX *c);
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28        int SHA224_Init(SHA256_CTX *c);
29        int SHA224_Update(SHA256_CTX *c, const void *data, size_t len);
30        int SHA224_Final(unsigned char *md, SHA256_CTX *c);
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32        int SHA256_Init(SHA256_CTX *c);
33        int SHA256_Update(SHA256_CTX *c, const void *data, size_t len);
34        int SHA256_Final(unsigned char *md, SHA256_CTX *c);
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36        int SHA384_Init(SHA512_CTX *c);
37        int SHA384_Update(SHA512_CTX *c, const void *data, size_t len);
38        int SHA384_Final(unsigned char *md, SHA512_CTX *c);
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40        int SHA512_Init(SHA512_CTX *c);
41        int SHA512_Update(SHA512_CTX *c, const void *data, size_t len);
42        int SHA512_Final(unsigned char *md, SHA512_CTX *c);
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DESCRIPTION

45       All of the functions described on this page except for SHA1(),
46       SHA224(), SHA256(), SHA384() and SHA512() are deprecated.  Applications
47       should instead use EVP_DigestInit_ex(3), EVP_DigestUpdate(3) and
48       EVP_DigestFinal_ex(3), or the quick one-shot function EVP_Q_digest(3).
49       SHA1(), SHA224(), SHA256(), SHA384(), and SHA256() can continue to be
50       used. They can also be replaced by, e.g.,
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52           (EVP_Q_digest(d, n, md, NULL, NULL, "SHA256", NULL) ? md : NULL)
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54       SHA-1 (Secure Hash Algorithm) is a cryptographic hash function with a
55       160 bit output.
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57       SHA1() computes the SHA-1 message digest of the n bytes at d and places
58       it in md (which must have space for SHA_DIGEST_LENGTH == 20 bytes of
59       output). If md is NULL, the digest is placed in a static array. Note:
60       setting md to NULL is not thread safe.
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62       The following functions may be used if the message is not completely
63       stored in memory:
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65       SHA1_Init() initializes a SHA_CTX structure.
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67       SHA1_Update() can be called repeatedly with chunks of the message to be
68       hashed (len bytes at data).
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70       SHA1_Final() places the message digest in md, which must have space for
71       SHA_DIGEST_LENGTH == 20 bytes of output, and erases the SHA_CTX.
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73       The SHA224, SHA256, SHA384 and SHA512 families of functions operate in
74       the same way as for the SHA1 functions. Note that SHA224 and SHA256 use
75       a SHA256_CTX object instead of SHA_CTX. SHA384 and SHA512 use
76       SHA512_CTX.  The buffer md must have space for the output from the SHA
77       variant being used (defined by SHA224_DIGEST_LENGTH,
78       SHA256_DIGEST_LENGTH, SHA384_DIGEST_LENGTH and SHA512_DIGEST_LENGTH).
79       Also note that, as for the SHA1() function above, the SHA224(),
80       SHA256(), SHA384() and SHA512() functions are not thread safe if md is
81       NULL.
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RETURN VALUES

84       SHA1(), SHA224(), SHA256(), SHA384() and SHA512() return a pointer to
85       the hash value.
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87       SHA1_Init(), SHA1_Update() and SHA1_Final() and equivalent SHA224,
88       SHA256, SHA384 and SHA512 functions return 1 for success, 0 otherwise.
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CONFORMING TO

91       US Federal Information Processing Standard FIPS PUB 180-4 (Secure Hash
92       Standard), ANSI X9.30
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SEE ALSO

95       EVP_Q_digest(3), EVP_DigestInit(3)
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HISTORY

98       All of these functions except SHA*() were deprecated in OpenSSL 3.0.
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101       Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
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103       Licensed under the Apache License 2.0 (the "License").  You may not use
104       this file except in compliance with the License.  You can obtain a copy
105       in the file LICENSE in the source distribution or at
106       <https://www.openssl.org/source/license.html>.
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1103.1.1                             2023-08-31                SHA256_INIT(3ossl)
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