1.\" Copyright (c) 1999 Kungliga Tekniska H�gskolan 2.\" $Id: krb5_create_checksum.3,v 1.4 2002/08/28 15:30:49 joda Exp $ 3.Dd April 7, 1999 4.Dt NAME 3 5.Os HEIMDAL 6.Sh NAME 7.Nm krb5_checksum_is_collision_proof , 8.Nm krb5_checksum_is_keyed , 9.Nm krb5_checksumsize , 10.Nm krb5_create_checksum , 11.Nm krb5_verify_checksum 12.Nd creates and verifies checksums 13.Sh LIBRARY 14Kerberos 5 Library (libkrb5, -lkrb5) 15.Sh SYNOPSIS 16.Fd #include <krb5.h> 17.Ft krb5_error_code 18.Fn krb5_create_checksum "krb5_context context" "krb5_crypto crypto" "unsigned usage_or_type" "void *data" "size_t len" "Checksum *result" 19.Ft krb5_error_code 20.Fn krb5_verify_checksum "krb5_context context" "krb5_crypto crypto" "krb5_key_usage usage" "void *data" "size_t len" "Checksum *cksum" 21.Ft krb5_boolean 22.Fn krb5_checksum_is_collision_proof "krb5_context context" "krb5_cksumtype type" 23.Ft krb5_boolean 24.Fn krb5_checksum_is_keyed "krb5_context context" "krb5_cksumtype type" 25.Sh DESCRIPTION 26These functions are used to create and verify checksums. 27.Fn krb5_create_checksum 28creates a checksum of the specified data, and puts it in 29.Fa result . 30If 31.Fa crypto 32is 33.Dv NULL , 34.Fa usage_or_type 35specifies the checksum type to use; it must not be keyed. Otherwise 36.Fa crypto 37is an encryption context created by 38.Fn krb5_crypto_init , 39and 40.Fa usage_or_type 41specifies a key-usage. 42.Pp 43.Fn krb5_verify_checksum 44verifies the 45.Fa checksum , 46against the provided data. 47.Pp 48.Fn krb5_checksum_is_collision_proof 49returns true is the specified checksum is collision proof (that it's 50very unlikely that two strings has the same hash value, and that it's 51hard to find two strings that has the same hash). Examples of 52collision proof checksums are MD5, and SHA1, while CRC32 is not. 53.Pp 54.Fn krb5_checksum_is_keyed 55returns true if the specified checksum type is keyed (that the hash 56value is a function of both the data, and a separate key). Examples of 57keyed hash algorithms are HMAC-SHA1-DES3, and RSA-MD5-DES. The 58.Dq plain 59hash functions MD5, and SHA1 are not keyed. 60.\" .Sh EXAMPLE 61.\" .Sh BUGS 62.Sh SEE ALSO 63.Xr krb5_crypto_init 3 , 64.Xr krb5_encrypt 3 65