xref: /freebsd/crypto/heimdal/lib/krb5/krb5_create_checksum.3 (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
1.\" Copyright (c) 1999 Kungliga Tekniska H�gskolan
2.\" (Royal Institute of Technology, Stockholm, Sweden).
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32.\" $Id: krb5_create_checksum.3,v 1.6 2003/04/16 13:58:14 lha Exp $
33.\"
34.Dd April  7, 1999
35.Dt NAME 3
36.Os HEIMDAL
37.Sh NAME
38.Nm krb5_checksum_is_collision_proof ,
39.Nm krb5_checksum_is_keyed ,
40.Nm krb5_checksumsize ,
41.Nm krb5_create_checksum ,
42.Nm krb5_verify_checksum
43.Nd creates and verifies checksums
44.Sh LIBRARY
45Kerberos 5 Library (libkrb5, -lkrb5)
46.Sh SYNOPSIS
47.In krb5.h
48.Ft krb5_error_code
49.Fn krb5_create_checksum "krb5_context context" "krb5_crypto crypto" "unsigned usage_or_type" "void *data" "size_t len" "Checksum *result"
50.Ft krb5_error_code
51.Fn krb5_verify_checksum "krb5_context context" "krb5_crypto crypto" "krb5_key_usage usage" "void *data" "size_t len" "Checksum *cksum"
52.Ft krb5_boolean
53.Fn krb5_checksum_is_collision_proof "krb5_context context" "krb5_cksumtype type"
54.Ft krb5_boolean
55.Fn krb5_checksum_is_keyed "krb5_context context" "krb5_cksumtype type"
56.Sh DESCRIPTION
57These functions are used to create and verify checksums.
58.Fn krb5_create_checksum
59creates a checksum of the specified data, and puts it in
60.Fa result .
61If
62.Fa crypto
63is
64.Dv NULL ,
65.Fa usage_or_type
66specifies the checksum type to use; it must not be keyed. Otherwise
67.Fa crypto
68is an encryption context created by
69.Fn krb5_crypto_init ,
70and
71.Fa usage_or_type
72specifies a key-usage.
73.Pp
74.Fn krb5_verify_checksum
75verifies the
76.Fa checksum ,
77against the provided data.
78.Pp
79.Fn krb5_checksum_is_collision_proof
80returns true is the specified checksum is collision proof (that it's
81very unlikely that two strings has the same hash value, and that it's
82hard to find two strings that has the same hash). Examples of
83collision proof checksums are MD5, and SHA1, while CRC32 is not.
84.Pp
85.Fn krb5_checksum_is_keyed
86returns true if the specified checksum type is keyed (that the hash
87value is a function of both the data, and a separate key). Examples of
88keyed hash algorithms are HMAC-SHA1-DES3, and RSA-MD5-DES. The
89.Dq plain
90hash functions MD5, and SHA1 are not keyed.
91.\" .Sh EXAMPLE
92.\" .Sh BUGS
93.Sh SEE ALSO
94.Xr krb5_crypto_init 3 ,
95.Xr krb5_encrypt 3
96