initial version

git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@5975 ec53bebd-3082-4978-b11e-865c3cabbd6b

lib/krb5/krb5_create_checksum.3

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+.\" Copyright (c) 1999 Kungliga Tekniska H<>gskolan
+.\" $Id$
+.Dd April  7, 1999
+.Dt NAME 3
+.Os HEIMDAL
+.Sh NAME
+.Nm krb5_checksum_is_collision_proof , 
+.Nm krb5_checksum_is_keyed , 
+.Nm krb5_checksumsize , 
+.Nm krb5_create_checksum , 
+.Nm krb5_verify_checksum
+.Nd creates and verifies checksums
+.Sh SYNOPSIS
+.Fd #include <krb5.h>
+
+.Ft krb5_error_code
+.Fn krb5_create_checksum "krb5_context context" "krb5_crypto crypto" "unsigned usage_or_type" "void *data" "size_t len" "Checksum *result"
+
+.Ft krb5_error_code
+.Fn krb5_verify_checksum "krb5_context context" "krb5_crypto crypto" "krb5_key_usage usage" "void *data" "size_t len" "Checksum *cksum"
+
+.Ft krb5_boolean
+.Fn krb5_checksum_is_collision_proof "krb5_context context" "krb5_cksumtype type"
+
+.Ft krb5_boolean
+.Fn krb5_checksum_is_keyed "krb5_context context" "krb5_cksumtype type"
+
+.Sh DESCRIPTION
+These functions are used to create and verify checksums.
+.Fn krb5_create_checksum 
+creates a checksum of the specified data, and puts it in
+.Fa result .
+If
+.Fa crypto
+is 
+.Dv NULL ,
+.Fa usage_or_type 
+specifies the checksum type to use; it must not be keyed. Otherwise 
+.Fa crypto
+is an encryption context created by
+.Fn krb5_crypto_init ,
+and
+.Fa usage_or_type
+specifies a key-usage.
+.Pp
+.Fn krb5_verify_checksum
+verifies the
+.Fa checksum ,
+against the provided data. 
+.Pp
+.Fn krb5_checksum_is_collision_proof
+returns true is the specified checksum is collision proof (that it's
+very unlikely that two strings has the same hash value, and that it's
+hard to find two strings that has the same hash). Examples of
+collision proof checksums are MD5, and SHA1, while CRC32 is not.
+.Pp
+.Fn krb5_checksum_is_keyed
+returns true if the specified checksum type is keyed (that the hash
+value is a function of both the data, and a separate key). Examples of
+keyed hash algorithms are HMAC-SHA1-DES3, and RSA-MD5-DES. The 
+.Dq plain
+hash functions MD5, and SHA1 are not keyed.
+
+.\" .Sh EXAMPLE
+.\" .Sh BUGS
+.Sh SEE ALSO
+.Xr krb5_crypto_init 3 ,
+.Xr krb5_encrypt 3