man/man3/krb5_crypto.3

     $NetBSD: krb5_crypto.3,v 1.3 2023/06/19 21:41:40 christos Exp $

 "krb5_crypto" 3 "Tue Nov 15 2022" "Version 7.8.0" "Heimdal Kerberos 5 library" \" -*- nroff -*-
 NAME
krb5_crypto - Heimdal Kerberos 5 cryptography functions
 SYNOPSIS


 "Functions"

 "HEIMDAL_WARN_UNUSED_RESULT_ATTRIBUTE KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_generate_random (void *buf, size_t len)"
 "KRB5_LIB_FUNCTION void KRB5_LIB_CALL krb5_generate_random_block (void *buf, size_t len)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_enctype_valid (krb5_context context, krb5_enctype etype)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_cksumtype_to_enctype (krb5_context context, krb5_cksumtype ctype, krb5_enctype *etype)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_encrypt_iov_ivec (krb5_context context, krb5_crypto crypto, unsigned usage, krb5_crypto_iov *data, int num_data, void *ivec)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_decrypt_iov_ivec (krb5_context context, krb5_crypto crypto, unsigned usage, krb5_crypto_iov *data, unsigned int num_data, void *ivec)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_create_checksum_iov (krb5_context context, krb5_crypto crypto, unsigned usage, krb5_crypto_iov *data, unsigned int num_data, krb5_cksumtype *type)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_verify_checksum_iov (krb5_context context, krb5_crypto crypto, unsigned usage, krb5_crypto_iov *data, unsigned int num_data, krb5_cksumtype *type)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_crypto_init (krb5_context context, const krb5_keyblock *key, krb5_enctype etype, krb5_crypto *crypto)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_crypto_destroy (krb5_context context, krb5_crypto crypto)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_crypto_getblocksize (krb5_context context, krb5_crypto crypto, size_t *blocksize)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_crypto_getenctype (krb5_context context, krb5_crypto crypto, krb5_enctype *enctype)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_crypto_getpadsize (krb5_context context, krb5_crypto crypto, size_t *padsize)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_crypto_getconfoundersize (krb5_context context, krb5_crypto crypto, size_t *confoundersize)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_enctype_disable (krb5_context context, krb5_enctype enctype)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_enctype_enable (krb5_context context, krb5_enctype enctype)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_allow_weak_crypto (krb5_context context, krb5_boolean enable)"
 "KRB5_LIB_FUNCTION krb5_boolean KRB5_LIB_CALL krb5_is_enctype_weak (krb5_context context, krb5_enctype enctype)"
 "KRB5_LIB_FUNCTION krb5_boolean KRB5_LIB_CALL _krb5_enctype_requires_random_salt (krb5_context context, krb5_enctype enctype)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_random_to_key (krb5_context context, krb5_enctype type, const void *data, size_t size, krb5_keyblock *key)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_crypto_fx_cf2 (krb5_context context, const krb5_crypto crypto1, const krb5_crypto crypto2, krb5_data *pepper1, krb5_data *pepper2, krb5_enctype enctype, krb5_keyblock *res)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_generate_subkey_extended (krb5_context context, const krb5_keyblock *key, krb5_enctype etype, krb5_keyblock **subkey)"
 "KRB5_LIB_FUNCTION void KRB5_LIB_CALL krb5_keyblock_zero (krb5_keyblock *keyblock)"
 "KRB5_LIB_FUNCTION void KRB5_LIB_CALL krb5_free_keyblock_contents (krb5_context context, krb5_keyblock *keyblock)"
 "KRB5_LIB_FUNCTION void KRB5_LIB_CALL krb5_free_keyblock (krb5_context context, krb5_keyblock *keyblock)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_copy_keyblock_contents (krb5_context context, const krb5_keyblock *inblock, krb5_keyblock *to)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_copy_keyblock (krb5_context context, const krb5_keyblock *inblock, krb5_keyblock **to)"
 "KRB5_LIB_FUNCTION krb5_enctype KRB5_LIB_CALL krb5_keyblock_get_enctype (const krb5_keyblock *block)"
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_keyblock_init (krb5_context context, krb5_enctype type, const void *data, size_t size, krb5_keyblock *key)"
 "krb5_error_code _krb5_SP800_108_HMAC_KDF (krb5_context context, const krb5_data *kdf_K1, const krb5_data *kdf_label, const krb5_data *kdf_context, const EVP_MD *md, krb5_data *kdf_K0)"
 "Detailed Description"


 "Function Documentation"

 "KRB5_LIB_FUNCTION krb5_boolean KRB5_LIB_CALL _krb5_enctype_requires_random_salt (krb5_context context, krb5_enctype enctype)"
Returns whether the encryption type should use randomly generated salts

Parameters

context Kerberos 5 context

enctype encryption type to probe


Returns

Returns true if generated salts should have random component


 "krb5_error_code _krb5_SP800_108_HMAC_KDF (krb5_context context, const krb5_data * kdf_K1, const krb5_data * kdf_label, const krb5_data * kdf_context, const EVP_MD * md, krb5_data * kdf_K0)"
As described in SP800-108 5.1 (for HMAC)

Parameters

context Kerberos 5 context

kdf_K1 Base key material.

kdf_label A string that identifies the purpose for the derived key.

kdf_context A binary string containing parties, nonce, etc.

md Message digest function to use for PRF.

kdf_K0 Derived key data.


Returns

Return an error code for an failure or 0 on success.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_allow_weak_crypto (krb5_context context, krb5_boolean enable)"
Enable or disable all weak encryption types

Parameters

context Kerberos 5 context

enable true to enable, false to disable


Returns

Return an error code or 0.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_cksumtype_to_enctype (krb5_context context, krb5_cksumtype ctype, krb5_enctype * etype)"
Return the coresponding encryption type for a checksum type.

Parameters

context Kerberos context

ctype The checksum type to get the result enctype for

etype The returned encryption, when the matching etype is not found, etype is set to ETYPE_NULL.


Returns

Return an error code for an failure or 0 on success.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_copy_keyblock (krb5_context context, const krb5_keyblock * inblock, krb5_keyblock ** to)"
Copy a keyblock, free the output keyblock with krb5_free_keyblock().

Parameters

context a Kerberos 5 context

inblock the key to copy

to the output key.


Returns

0 on success or a Kerberos 5 error code


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_copy_keyblock_contents (krb5_context context, const krb5_keyblock * inblock, krb5_keyblock * to)"
Copy a keyblock, free the output keyblock with krb5_free_keyblock_contents().

Parameters

context a Kerberos 5 context

inblock the key to copy

to the output key.


Returns

0 on success or a Kerberos 5 error code


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_create_checksum_iov (krb5_context context, krb5_crypto crypto, unsigned usage, krb5_crypto_iov * data, unsigned int num_data, krb5_cksumtype * type)"
Create a Kerberos message checksum.

Parameters

context Kerberos context

crypto Kerberos crypto context

usage Key usage for this buffer

data array of buffers to process

num_data length of array

type output data


Returns

Return an error code or 0.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_crypto_destroy (krb5_context context, krb5_crypto crypto)"
Free a crypto context created by krb5_crypto_init().

Parameters

context Kerberos context

crypto crypto context to free


Returns

Return an error code or 0.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_crypto_fx_cf2 (krb5_context context, const krb5_crypto crypto1, const krb5_crypto crypto2, krb5_data * pepper1, krb5_data * pepper2, krb5_enctype enctype, krb5_keyblock * res)"
The FX-CF2 key derivation function, used in FAST and preauth framework.

Parameters

context Kerberos 5 context

crypto1 first key to combine

crypto2 second key to combine

pepper1 factor to combine with first key to garante uniqueness

pepper2 factor to combine with second key to garante uniqueness

enctype the encryption type of the resulting key

res allocated key, free with krb5_free_keyblock_contents()


Returns

Return an error code or 0.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_crypto_getblocksize (krb5_context context, krb5_crypto crypto, size_t * blocksize)"
Return the blocksize used algorithm referenced by the crypto context

Parameters

context Kerberos context

crypto crypto context to query

blocksize the resulting blocksize


Returns

Return an error code or 0.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_crypto_getconfoundersize (krb5_context context, krb5_crypto crypto, size_t * confoundersize)"
Return the confounder size used by the crypto context

Parameters

context Kerberos context

crypto crypto context to query

confoundersize the returned confounder size


Returns

Return an error code or 0.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_crypto_getenctype (krb5_context context, krb5_crypto crypto, krb5_enctype * enctype)"
Return the encryption type used by the crypto context

Parameters

context Kerberos context

crypto crypto context to query

enctype the resulting encryption type


Returns

Return an error code or 0.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_crypto_getpadsize (krb5_context context, krb5_crypto crypto, size_t * padsize)"
Return the padding size used by the crypto context

Parameters

context Kerberos context

crypto crypto context to query

padsize the return padding size


Returns

Return an error code or 0.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_crypto_init (krb5_context context, const krb5_keyblock * key, krb5_enctype etype, krb5_crypto * crypto)"
Create a crypto context used for all encryption and signature operation. The encryption type to use is taken from the key, but can be overridden with the enctype parameter. This can be useful for encryptions types which is compatiable (DES for example).

To free the crypto context, use krb5_crypto_destroy().

Parameters

context Kerberos context

key the key block information with all key data

etype the encryption type

crypto the resulting crypto context


Returns

Return an error code or 0.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_decrypt_iov_ivec (krb5_context context, krb5_crypto crypto, unsigned usage, krb5_crypto_iov * data, unsigned int num_data, void * ivec)"
Inline decrypt a Kerberos message.

Parameters

context Kerberos context

crypto Kerberos crypto context

usage Key usage for this buffer

data array of buffers to process

num_data length of array

ivec initial cbc/cts vector


Returns

Return an error code or 0.


 "1." 4
KRB5_CRYPTO_TYPE_HEADER
 "2." 4
one KRB5_CRYPTO_TYPE_DATA and array [0,...] of KRB5_CRYPTO_TYPE_SIGN_ONLY in any order, however the receiver have to aware of the order. KRB5_CRYPTO_TYPE_SIGN_ONLY is commonly used unencrypoted protocol headers and trailers. The output data will be of same size as the input data or shorter.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_encrypt_iov_ivec (krb5_context context, krb5_crypto crypto, unsigned usage, krb5_crypto_iov * data, int num_data, void * ivec)"
Inline encrypt a kerberos message

Parameters

context Kerberos context

crypto Kerberos crypto context

usage Key usage for this buffer

data array of buffers to process

num_data length of array

ivec initial cbc/cts vector


Returns

Return an error code or 0.


Kerberos encrypted data look like this:

 "1." 4
KRB5_CRYPTO_TYPE_HEADER
 "2." 4
array [1,...] KRB5_CRYPTO_TYPE_DATA and array [0,...] KRB5_CRYPTO_TYPE_SIGN_ONLY in any order, however the receiver have to aware of the order. KRB5_CRYPTO_TYPE_SIGN_ONLY is commonly used headers and trailers.
 "3." 4
KRB5_CRYPTO_TYPE_PADDING, at least on padsize long if padsize > 1
 "4." 4
KRB5_CRYPTO_TYPE_TRAILER


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_enctype_disable (krb5_context context, krb5_enctype enctype)"
Disable encryption type

Parameters

context Kerberos 5 context

enctype encryption type to disable


Returns

Return an error code or 0.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_enctype_enable (krb5_context context, krb5_enctype enctype)"
Enable encryption type

Parameters

context Kerberos 5 context

enctype encryption type to enable


Returns

Return an error code or 0.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_enctype_valid (krb5_context context, krb5_enctype etype)"
Check if a enctype is valid, return 0 if it is.

Parameters

context Kerberos context

etype enctype to check if its valid or not


Returns

Return an error code for an failure or 0 on success (enctype valid).


 "KRB5_LIB_FUNCTION void KRB5_LIB_CALL krb5_free_keyblock (krb5_context context, krb5_keyblock * keyblock)"
Free a keyblock, also zero out the content of the keyblock, uses krb5_free_keyblock_contents() to free the content.

Parameters

context a Kerberos 5 context

keyblock keyblock to free, NULL is valid argument


 "KRB5_LIB_FUNCTION void KRB5_LIB_CALL krb5_free_keyblock_contents (krb5_context context, krb5_keyblock * keyblock)"
Free a keyblock's content, also zero out the content of the keyblock.

Parameters

context a Kerberos 5 context

keyblock keyblock content to free, NULL is valid argument


 "HEIMDAL_WARN_UNUSED_RESULT_ATTRIBUTE KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_generate_random (void * buf, size_t len)"
Fill buffer buf with len bytes of PRNG randomness that is ok to use for key generation, padding and public diclosing the randomness w/o disclosing the randomness source.

This function can fail, and callers must check the return value.

Parameters

buf a buffer to fill with randomness

len length of memory that buf points to.


Returns

return 0 on success or HEIM_ERR_RANDOM_OFFLINE if the funcation failed to initialize the randomness source.


 "KRB5_LIB_FUNCTION void KRB5_LIB_CALL krb5_generate_random_block (void * buf, size_t len)"
Fill buffer buf with len bytes of PRNG randomness that is ok to use for key generation, padding and public diclosing the randomness w/o disclosing the randomness source.

This function can NOT fail, instead it will abort() and program will crash.

If this function is called after a successful krb5_init_context(), the chance of it failing is low due to that krb5_init_context() pulls out some random, and quite commonly the randomness sources will not fail once it have started to produce good output, /dev/urandom behavies that way.

Parameters

buf a buffer to fill with randomness

len length of memory that buf points to.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_generate_subkey_extended (krb5_context context, const krb5_keyblock * key, krb5_enctype etype, krb5_keyblock ** subkey)"
Generate subkey, from keyblock

Parameters

context kerberos context

key session key

etype encryption type of subkey, if ETYPE_NULL, use key's enctype

subkey returned new, free with krb5_free_keyblock().


Returns

0 on success or a Kerberos 5 error code


 "KRB5_LIB_FUNCTION krb5_boolean KRB5_LIB_CALL krb5_is_enctype_weak (krb5_context context, krb5_enctype enctype)"
Returns is the encryption is strong or weak

Parameters

context Kerberos 5 context

enctype encryption type to probe


Returns

Returns true if encryption type is weak or is not supported.


 "KRB5_LIB_FUNCTION krb5_enctype KRB5_LIB_CALL krb5_keyblock_get_enctype (const krb5_keyblock * block)"
Get encryption type of a keyblock.
 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_keyblock_init (krb5_context context, krb5_enctype type, const void * data, size_t size, krb5_keyblock * key)"
Fill in `key' with key data of type `enctype' from `data' of length `size'. Key should be freed using krb5_free_keyblock_contents().

Returns

0 on success or a Kerberos 5 error code


 "KRB5_LIB_FUNCTION void KRB5_LIB_CALL krb5_keyblock_zero (krb5_keyblock * keyblock)"
Zero out a keyblock

Parameters

keyblock keyblock to zero out


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_random_to_key (krb5_context context, krb5_enctype type, const void * data, size_t size, krb5_keyblock * key)"
Converts the random bytestring to a protocol key according to Kerberos crypto frame work. It may be assumed that all the bits of the input string are equally random, even though the entropy present in the random source may be limited.

Parameters

context Kerberos 5 context

type the enctype resulting key will be of

data input random data to convert to a key

size size of input random data, at least krb5_enctype_keysize() long

key key, output key, free with krb5_free_keyblock_contents()


Returns

Return an error code or 0.


 "KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_verify_checksum_iov (krb5_context context, krb5_crypto crypto, unsigned usage, krb5_crypto_iov * data, unsigned int num_data, krb5_cksumtype * type)"
Verify a Kerberos message checksum.

Parameters

context Kerberos context

crypto Kerberos crypto context

usage Key usage for this buffer

data array of buffers to process

num_data length of array

type return checksum type if not NULL


Returns

Return an error code or 0.


 "Author"

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