LIBRARY

Kerberos 5 Library (libkrb5, -lkrb5)

SYNOPSIS

In krb5.h

typedef Checksum krb5_checksum; Ft void Fo krb5_checksum_disable Fa krb5_context context Fa krb5_cksumtype type Fc Ft krb5_boolean Fo krb5_checksum_is_collision_proof Fa krb5_context context Fa krb5_cksumtype type Fc Ft krb5_boolean Fo krb5_checksum_is_keyed Fa krb5_context context Fa krb5_cksumtype type Fc Ft krb5_error_code Fo krb5_cksumtype_valid Fa krb5_context context Fa krb5_cksumtype ctype Fc Ft krb5_error_code Fo krb5_checksumsize Fa krb5_context context Fa krb5_cksumtype type Fa size_t *size Fc Ft krb5_error_code Fo krb5_create_checksum Fa krb5_context context Fa krb5_crypto crypto Fa krb5_key_usage usage Fa int type Fa void *data Fa size_t len Fa Checksum *result Fc Ft krb5_error_code Fo krb5_verify_checksum Fa krb5_context context Fa krb5_crypto crypto Fa krb5_key_usage usage Fa void *data Fa size_t len Fa Checksum *cksum Fc Ft krb5_error_code Fo krb5_crypto_get_checksum_type Fa krb5_context context Fa krb5_crypto crypto Fa krb5_cksumtype *type Fc Ft void Fo krb5_free_checksum Fa krb5_context context Fa krb5_checksum *cksum Fc Ft void Fo krb5_free_checksum_contents Fa krb5_context context Fa krb5_checksum *cksum Fc Ft krb5_error_code Fo krb5_hmac Fa krb5_context context Fa krb5_cksumtype cktype Fa const void *data Fa size_t len Fa unsigned usage Fa krb5_keyblock *key Fa Checksum *result Fc Ft krb5_error_code Fo krb5_copy_checksum Fa krb5_context context Fa const krb5_checksum *old Fa krb5_checksum **new Fc

DESCRIPTION

The krb5_checksum structure holds a Kerberos checksum. There is no component inside krb5_checksum that is directly referable.

The 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 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.

Fn krb5_verify_checksum verifies the Fa checksum against the provided data.

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.

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 ``plain'' hash functions MD5, and SHA1 are not keyed.

Fn krb5_crypto_get_checksum_type returns the checksum type that will be used when creating a checksum for the given Fa crypto context. This function is useful in combination with Fn krb5_checksumsize when you want to know the size a checksum will use when you create it.

Fn krb5_cksumtype_valid returns 0 or an error if the checksumtype is implemented and not currently disabled in this kerberos library.

Fn krb5_checksumsize returns the size of the outdata of checksum function.

Fn krb5_copy_checksum returns a copy of the checksum Fn krb5_free_checksum should use used to free the Fa new checksum.

Fn krb5_free_checksum free the checksum and the content of the checksum.

Fn krb5_free_checksum_contents frees the content of checksum in Fa cksum .

Fn krb5_hmac calculates the HMAC over Fa data (with length Fa len ) using the keyusage Fa usage and keyblock Fa key . Note that keyusage is not always used in checksums.

krb5_checksum_disable globally disables the checksum type.