2 .\" ----------------------------------------------------------------------------
3 .\" "THE BEER-WARE LICENSE" (Revision 42):
4 .\" <phk@FreeBSD.org> wrote this file. As long as you retain this notice you
5 .\" can do whatever you want with this stuff. If we meet some day, and you think
6 .\" this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
7 .\" ----------------------------------------------------------------------------
9 .\" From: Id: mdX.3,v 1.14 1999/02/11 20:31:49 wollman Exp
21 .Nm SHA512_FileChunk ,
28 .Nm SHA384_FileChunk ,
31 .Nm SHA512_256_Update ,
32 .Nm SHA512_256_Final ,
35 .Nm SHA512_256_FileChunk ,
37 .Nd calculate the FIPS 180-4 ``SHA-512'' family of message digests
44 .Fn SHA512_Init "SHA512_CTX *context"
46 .Fn SHA512_Update "SHA512_CTX *context" "const unsigned char *data" "size_t len"
48 .Fn SHA512_Final "unsigned char digest[64]" "SHA512_CTX *context"
50 .Fn SHA512_End "SHA512_CTX *context" "char *buf"
52 .Fn SHA512_File "const char *filename" "char *buf"
54 .Fn SHA512_FileChunk "const char *filename" "char *buf" "off_t offset" "off_t length"
56 .Fn SHA512_Data "const unsigned char *data" "unsigned int len" "char *buf"
59 .Fn SHA384_Init "SHA384_CTX *context"
61 .Fn SHA384_Update "SHA384_CTX *context" "const unsigned char *data" "size_t len"
63 .Fn SHA384_Final "unsigned char digest[48]" "SHA384_CTX *context"
65 .Fn SHA384_End "SHA384_CTX *context" "char *buf"
67 .Fn SHA384_File "const char *filename" "char *buf"
69 .Fn SHA384_FileChunk "const char *filename" "char *buf" "off_t offset" "off_t length"
71 .Fn SHA384_Data "const unsigned char *data" "unsigned int len" "char *buf"
74 .Fn SHA512_256_Init "SHA512_CTX *context"
76 .Fn SHA512_256_Update "SHA512_CTX *context" "const unsigned char *data" "size_t len"
78 .Fn SHA512_256_Final "unsigned char digest[32]" "SHA512_CTX *context"
80 .Fn SHA512_256_End "SHA512_CTX *context" "char *buf"
82 .Fn SHA512_256_File "const char *filename" "char *buf"
84 .Fn SHA512_256_FileChunk "const char *filename" "char *buf" "off_t offset" "off_t length"
86 .Fn SHA512_256_Data "const unsigned char *data" "unsigned int len" "char *buf"
90 functions calculate a 512-bit cryptographic checksum (digest)
91 for any number of input bytes.
92 A cryptographic checksum is a one-way
93 hash function; that is, it is computationally impractical to find
94 the input corresponding to a particular output.
98 of the input-data, which does not disclose the actual input.
105 functions are the core functions.
110 run over the data with
112 and finally extract the result using
118 which converts the return value to a 129-character
119 (including the terminating '\e0')
121 string which represents the 512 bits in hexadecimal.
124 calculates the digest of a file, and uses
126 to return the result.
127 If the file cannot be opened, a null pointer is returned.
131 but it only calculates the digest over a byte-range of the file specified,
139 parameter is specified as 0, or more than the length of the remaining part
142 calculates the digest from
146 calculates the digest of a chunk of data in memory, and uses
148 to return the result.
157 argument can be a null pointer, in which case the returned string
160 and subsequently must be explicitly deallocated using
165 argument is non-null it must point to at least 129 characters of buffer space.
171 functions are identical to the
173 functions except they use a different initial hash value and the output is
174 truncated to 384 bits and 256 bits respectively.
179 which converts the return value to a 97-character
180 (including the terminating '\e0')
182 string which represents the 384 bits in hexadecimal.
187 which converts the return value to a 65-character
188 (including the terminating '\e0')
190 string which represents the 256 bits in hexadecimal.
200 These functions appeared in
203 The core hash routines were implemented by Colin Percival based on
208 No method is known to exist which finds two files having the same hash value,
209 nor to find a file with a specific hash value.
210 There is on the other hand no guarantee that such a method does not exist.