Provided by: libssl-doc_3.0.5-2ubuntu1_all 
NAME
EVP_CIPHER_fetch, EVP_CIPHER_up_ref, EVP_CIPHER_free, EVP_CIPHER_CTX_new,
EVP_CIPHER_CTX_reset, EVP_CIPHER_CTX_free, EVP_EncryptInit_ex, EVP_EncryptInit_ex2,
EVP_EncryptUpdate, EVP_EncryptFinal_ex, EVP_DecryptInit_ex, EVP_DecryptInit_ex2,
EVP_DecryptUpdate, EVP_DecryptFinal_ex, EVP_CipherInit_ex, EVP_CipherInit_ex2,
EVP_CipherUpdate, EVP_CipherFinal_ex, EVP_CIPHER_CTX_set_key_length, EVP_CIPHER_CTX_ctrl,
EVP_EncryptInit, EVP_EncryptFinal, EVP_DecryptInit, EVP_DecryptFinal, EVP_CipherInit,
EVP_CipherFinal, EVP_Cipher, EVP_get_cipherbyname, EVP_get_cipherbynid,
EVP_get_cipherbyobj, EVP_CIPHER_is_a, EVP_CIPHER_get0_name, EVP_CIPHER_get0_description,
EVP_CIPHER_names_do_all, EVP_CIPHER_get0_provider, EVP_CIPHER_get_nid,
EVP_CIPHER_get_params, EVP_CIPHER_gettable_params, EVP_CIPHER_get_block_size,
EVP_CIPHER_get_key_length, EVP_CIPHER_get_iv_length, EVP_CIPHER_get_flags,
EVP_CIPHER_get_mode, EVP_CIPHER_get_type, EVP_CIPHER_CTX_cipher,
EVP_CIPHER_CTX_get0_cipher, EVP_CIPHER_CTX_get1_cipher, EVP_CIPHER_CTX_get0_name,
EVP_CIPHER_CTX_get_nid, EVP_CIPHER_CTX_get_params, EVP_CIPHER_gettable_ctx_params,
EVP_CIPHER_CTX_gettable_params, EVP_CIPHER_CTX_set_params, EVP_CIPHER_settable_ctx_params,
EVP_CIPHER_CTX_settable_params, EVP_CIPHER_CTX_get_block_size,
EVP_CIPHER_CTX_get_key_length, EVP_CIPHER_CTX_get_iv_length,
EVP_CIPHER_CTX_get_tag_length, EVP_CIPHER_CTX_get_app_data, EVP_CIPHER_CTX_set_app_data,
EVP_CIPHER_CTX_flags, EVP_CIPHER_CTX_set_flags, EVP_CIPHER_CTX_clear_flags,
EVP_CIPHER_CTX_test_flags, EVP_CIPHER_CTX_get_type, EVP_CIPHER_CTX_get_mode,
EVP_CIPHER_CTX_get_num, EVP_CIPHER_CTX_set_num, EVP_CIPHER_CTX_is_encrypting,
EVP_CIPHER_param_to_asn1, EVP_CIPHER_asn1_to_param, EVP_CIPHER_CTX_set_padding,
EVP_enc_null, EVP_CIPHER_do_all_provided, EVP_CIPHER_nid, EVP_CIPHER_name,
EVP_CIPHER_block_size, EVP_CIPHER_key_length, EVP_CIPHER_iv_length, EVP_CIPHER_flags,
EVP_CIPHER_mode, EVP_CIPHER_type, EVP_CIPHER_CTX_encrypting, EVP_CIPHER_CTX_nid,
EVP_CIPHER_CTX_block_size, EVP_CIPHER_CTX_key_length, EVP_CIPHER_CTX_iv_length,
EVP_CIPHER_CTX_tag_length, EVP_CIPHER_CTX_num, EVP_CIPHER_CTX_type, EVP_CIPHER_CTX_mode -
EVP cipher routines
SYNOPSIS
#include <openssl/evp.h>
EVP_CIPHER *EVP_CIPHER_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
const char *properties);
int EVP_CIPHER_up_ref(EVP_CIPHER *cipher);
void EVP_CIPHER_free(EVP_CIPHER *cipher);
EVP_CIPHER_CTX *EVP_CIPHER_CTX_new(void);
int EVP_CIPHER_CTX_reset(EVP_CIPHER_CTX *ctx);
void EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx);
int EVP_EncryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
ENGINE *impl, const unsigned char *key, const unsigned char *iv);
int EVP_EncryptInit_ex2(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
const unsigned char *key, const unsigned char *iv,
const OSSL_PARAM params[]);
int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
int *outl, const unsigned char *in, int inl);
int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl);
int EVP_DecryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
ENGINE *impl, const unsigned char *key, const unsigned char *iv);
int EVP_DecryptInit_ex2(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
const unsigned char *key, const unsigned char *iv,
const OSSL_PARAM params[]);
int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
int *outl, const unsigned char *in, int inl);
int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl);
int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
ENGINE *impl, const unsigned char *key, const unsigned char *iv, int enc);
int EVP_CipherInit_ex2(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
const unsigned char *key, const unsigned char *iv,
int enc, const OSSL_PARAM params[]);
int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
int *outl, const unsigned char *in, int inl);
int EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl);
int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
const unsigned char *key, const unsigned char *iv);
int EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl);
int EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
const unsigned char *key, const unsigned char *iv);
int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl);
int EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
const unsigned char *key, const unsigned char *iv, int enc);
int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl);
int EVP_Cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
const unsigned char *in, unsigned int inl);
int EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *x, int padding);
int EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *x, int keylen);
int EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *ctx, int cmd, int p1, void *p2);
int EVP_CIPHER_CTX_rand_key(EVP_CIPHER_CTX *ctx, unsigned char *key);
void EVP_CIPHER_CTX_set_flags(EVP_CIPHER_CTX *ctx, int flags);
void EVP_CIPHER_CTX_clear_flags(EVP_CIPHER_CTX *ctx, int flags);
int EVP_CIPHER_CTX_test_flags(const EVP_CIPHER_CTX *ctx, int flags);
const EVP_CIPHER *EVP_get_cipherbyname(const char *name);
const EVP_CIPHER *EVP_get_cipherbynid(int nid);
const EVP_CIPHER *EVP_get_cipherbyobj(const ASN1_OBJECT *a);
int EVP_CIPHER_get_nid(const EVP_CIPHER *e);
int EVP_CIPHER_is_a(const EVP_CIPHER *cipher, const char *name);
int EVP_CIPHER_names_do_all(const EVP_CIPHER *cipher,
void (*fn)(const char *name, void *data),
void *data);
const char *EVP_CIPHER_get0_name(const EVP_CIPHER *cipher);
const char *EVP_CIPHER_get0_description(const EVP_CIPHER *cipher);
const OSSL_PROVIDER *EVP_CIPHER_get0_provider(const EVP_CIPHER *cipher);
int EVP_CIPHER_get_block_size(const EVP_CIPHER *e);
int EVP_CIPHER_get_key_length(const EVP_CIPHER *e);
int EVP_CIPHER_get_iv_length(const EVP_CIPHER *e);
unsigned long EVP_CIPHER_get_flags(const EVP_CIPHER *e);
unsigned long EVP_CIPHER_get_mode(const EVP_CIPHER *e);
int EVP_CIPHER_get_type(const EVP_CIPHER *cipher);
const EVP_CIPHER *EVP_CIPHER_CTX_get0_cipher(const EVP_CIPHER_CTX *ctx);
EVP_CIPHER *EVP_CIPHER_CTX_get1_cipher(const EVP_CIPHER_CTX *ctx);
int EVP_CIPHER_CTX_get_nid(const EVP_CIPHER_CTX *ctx);
const char *EVP_CIPHER_CTX_get0_name(const EVP_CIPHER_CTX *ctx);
int EVP_CIPHER_get_params(EVP_CIPHER *cipher, OSSL_PARAM params[]);
int EVP_CIPHER_CTX_set_params(EVP_CIPHER_CTX *ctx, const OSSL_PARAM params[]);
int EVP_CIPHER_CTX_get_params(EVP_CIPHER_CTX *ctx, OSSL_PARAM params[]);
const OSSL_PARAM *EVP_CIPHER_gettable_params(const EVP_CIPHER *cipher);
const OSSL_PARAM *EVP_CIPHER_settable_ctx_params(const EVP_CIPHER *cipher);
const OSSL_PARAM *EVP_CIPHER_gettable_ctx_params(const EVP_CIPHER *cipher);
const OSSL_PARAM *EVP_CIPHER_CTX_settable_params(EVP_CIPHER_CTX *ctx);
const OSSL_PARAM *EVP_CIPHER_CTX_gettable_params(EVP_CIPHER_CTX *ctx);
int EVP_CIPHER_CTX_get_block_size(const EVP_CIPHER_CTX *ctx);
int EVP_CIPHER_CTX_get_key_length(const EVP_CIPHER_CTX *ctx);
int EVP_CIPHER_CTX_get_iv_length(const EVP_CIPHER_CTX *ctx);
int EVP_CIPHER_CTX_get_tag_length(const EVP_CIPHER_CTX *ctx);
void *EVP_CIPHER_CTX_get_app_data(const EVP_CIPHER_CTX *ctx);
void EVP_CIPHER_CTX_set_app_data(const EVP_CIPHER_CTX *ctx, void *data);
int EVP_CIPHER_CTX_get_type(const EVP_CIPHER_CTX *ctx);
int EVP_CIPHER_CTX_get_mode(const EVP_CIPHER_CTX *ctx);
int EVP_CIPHER_CTX_get_num(const EVP_CIPHER_CTX *ctx);
int EVP_CIPHER_CTX_set_num(EVP_CIPHER_CTX *ctx, int num);
int EVP_CIPHER_CTX_is_encrypting(const EVP_CIPHER_CTX *ctx);
int EVP_CIPHER_param_to_asn1(EVP_CIPHER_CTX *c, ASN1_TYPE *type);
int EVP_CIPHER_asn1_to_param(EVP_CIPHER_CTX *c, ASN1_TYPE *type);
void EVP_CIPHER_do_all_provided(OSSL_LIB_CTX *libctx,
void (*fn)(EVP_CIPHER *cipher, void *arg),
void *arg);
#define EVP_CIPHER_nid EVP_CIPHER_get_nid
#define EVP_CIPHER_name EVP_CIPHER_get0_name
#define EVP_CIPHER_block_size EVP_CIPHER_get_block_size
#define EVP_CIPHER_key_length EVP_CIPHER_get_key_length
#define EVP_CIPHER_iv_length EVP_CIPHER_get_iv_length
#define EVP_CIPHER_flags EVP_CIPHER_get_flags
#define EVP_CIPHER_mode EVP_CIPHER_get_mode
#define EVP_CIPHER_type EVP_CIPHER_get_type
#define EVP_CIPHER_CTX_encrypting EVP_CIPHER_CTX_is_encrypting
#define EVP_CIPHER_CTX_nid EVP_CIPHER_CTX_get_nid
#define EVP_CIPHER_CTX_block_size EVP_CIPHER_CTX_get_block_size
#define EVP_CIPHER_CTX_key_length EVP_CIPHER_CTX_get_key_length
#define EVP_CIPHER_CTX_iv_length EVP_CIPHER_CTX_get_iv_length
#define EVP_CIPHER_CTX_tag_length EVP_CIPHER_CTX_get_tag_length
#define EVP_CIPHER_CTX_num EVP_CIPHER_CTX_get_num
#define EVP_CIPHER_CTX_type EVP_CIPHER_CTX_get_type
#define EVP_CIPHER_CTX_mode EVP_CIPHER_CTX_get_mode
The following function has been deprecated since OpenSSL 3.0, and can be hidden entirely
by defining OPENSSL_API_COMPAT with a suitable version value, see openssl_user_macros(7):
const EVP_CIPHER *EVP_CIPHER_CTX_cipher(const EVP_CIPHER_CTX *ctx);
The following function has been deprecated since OpenSSL 1.1.0, and can be hidden entirely
by defining OPENSSL_API_COMPAT with a suitable version value, see openssl_user_macros(7):
int EVP_CIPHER_CTX_flags(const EVP_CIPHER_CTX *ctx);
DESCRIPTION
The EVP cipher routines are a high-level interface to certain symmetric ciphers.
The EVP_CIPHER type is a structure for cipher method implementation.
EVP_CIPHER_fetch()
Fetches the cipher implementation for the given algorithm from any provider offering
it, within the criteria given by the properties. See "ALGORITHM FETCHING" in
crypto(7) for further information.
The returned value must eventually be freed with EVP_CIPHER_free().
Fetched EVP_CIPHER structures are reference counted.
EVP_CIPHER_up_ref()
Increments the reference count for an EVP_CIPHER structure.
EVP_CIPHER_free()
Decrements the reference count for the fetched EVP_CIPHER structure. If the reference
count drops to 0 then the structure is freed.
EVP_CIPHER_CTX_new()
Allocates and returns a cipher context.
EVP_CIPHER_CTX_free()
Clears all information from a cipher context and frees any allocated memory associated
with it, including ctx itself. This function should be called after all operations
using a cipher are complete so sensitive information does not remain in memory.
EVP_CIPHER_CTX_ctrl()
This is a legacy method. EVP_CIPHER_CTX_set_params() and EVP_CIPHER_CTX_get_params()
is the mechanism that should be used to set and get parameters that are used by
providers.
Performs cipher-specific control actions on context ctx. The control command is
indicated in cmd and any additional arguments in p1 and p2. EVP_CIPHER_CTX_ctrl()
must be called after EVP_CipherInit_ex2(). Other restrictions may apply depending on
the control type and cipher implementation.
If this function happens to be used with a fetched EVP_CIPHER, it will translate the
controls that are known to OpenSSL into OSSL_PARAM(3) parameters with keys defined by
OpenSSL and call EVP_CIPHER_CTX_get_params() or EVP_CIPHER_CTX_set_params() as is
appropriate for each control command.
See "CONTROLS" below for more information, including what translations are being done.
EVP_CIPHER_get_params()
Retrieves the requested list of algorithm params from a CIPHER cipher. See
"PARAMETERS" below for more information.
EVP_CIPHER_CTX_get_params()
Retrieves the requested list of params from CIPHER context ctx. See "PARAMETERS"
below for more information.
EVP_CIPHER_CTX_set_params()
Sets the list of params into a CIPHER context ctx. See "PARAMETERS" below for more
information.
EVP_CIPHER_gettable_params()
Get a constant OSSL_PARAM array that describes the retrievable parameters that can be
used with EVP_CIPHER_get_params(). See OSSL_PARAM(3) for the use of OSSL_PARAM as a
parameter descriptor.
EVP_CIPHER_gettable_ctx_params() and EVP_CIPHER_CTX_gettable_params()
Get a constant OSSL_PARAM array that describes the retrievable parameters that can be
used with EVP_CIPHER_CTX_get_params(). EVP_CIPHER_gettable_ctx_params() returns the
parameters that can be retrieved from the algorithm, whereas
EVP_CIPHER_CTX_gettable_params() returns the parameters that can be retrieved in the
context's current state. See OSSL_PARAM(3) for the use of OSSL_PARAM as a parameter
descriptor.
EVP_CIPHER_settable_ctx_params() and EVP_CIPHER_CTX_settable_params()
Get a constant OSSL_PARAM array that describes the settable parameters that can be
used with EVP_CIPHER_CTX_set_params(). EVP_CIPHER_settable_ctx_params() returns the
parameters that can be set from the algorithm, whereas
EVP_CIPHER_CTX_settable_params() returns the parameters that can be set in the
context's current state. See OSSL_PARAM(3) for the use of OSSL_PARAM as a parameter
descriptor.
EVP_EncryptInit_ex2()
Sets up cipher context ctx for encryption with cipher type. type is typically supplied
by calling EVP_CIPHER_fetch(). type may also be set using legacy functions such as
EVP_aes_256_cbc(), but this is not recommended for new applications. key is the
symmetric key to use and iv is the IV to use (if necessary), the actual number of
bytes used for the key and IV depends on the cipher. The parameters params will be set
on the context after initialisation. It is possible to set all parameters to NULL
except type in an initial call and supply the remaining parameters in subsequent
calls, all of which have type set to NULL. This is done when the default cipher
parameters are not appropriate. For EVP_CIPH_GCM_MODE the IV will be generated
internally if it is not specified.
EVP_EncryptInit_ex()
This legacy function is similar to EVP_EncryptInit_ex2() when impl is NULL. The
implementation of the type from the impl engine will be used if it exists.
EVP_EncryptUpdate()
Encrypts inl bytes from the buffer in and writes the encrypted version to out. This
function can be called multiple times to encrypt successive blocks of data. The amount
of data written depends on the block alignment of the encrypted data. For most
ciphers and modes, the amount of data written can be anything from zero bytes to (inl
+ cipher_block_size - 1) bytes. For wrap cipher modes, the amount of data written can
be anything from zero bytes to (inl + cipher_block_size) bytes. For stream ciphers,
the amount of data written can be anything from zero bytes to inl bytes. Thus, out
should contain sufficient room for the operation being performed. The actual number
of bytes written is placed in outl. It also checks if in and out are partially
overlapping, and if they are 0 is returned to indicate failure.
If padding is enabled (the default) then EVP_EncryptFinal_ex() encrypts the "final"
data, that is any data that remains in a partial block. It uses standard block
padding (aka PKCS padding) as described in the NOTES section, below. The encrypted
final data is written to out which should have sufficient space for one cipher block.
The number of bytes written is placed in outl. After this function is called the
encryption operation is finished and no further calls to EVP_EncryptUpdate() should be
made.
If padding is disabled then EVP_EncryptFinal_ex() will not encrypt any more data and
it will return an error if any data remains in a partial block: that is if the total
data length is not a multiple of the block size.
EVP_DecryptInit_ex2(), EVP_DecryptInit_ex(), EVP_DecryptUpdate() and EVP_DecryptFinal_ex()
These functions are the corresponding decryption operations. EVP_DecryptFinal() will
return an error code if padding is enabled and the final block is not correctly
formatted. The parameters and restrictions are identical to the encryption operations
except that if padding is enabled the decrypted data buffer out passed to
EVP_DecryptUpdate() should have sufficient room for (inl + cipher_block_size) bytes
unless the cipher block size is 1 in which case inl bytes is sufficient.
EVP_CipherInit_ex2(), EVP_CipherInit_ex(), EVP_CipherUpdate() and EVP_CipherFinal_ex()
These functions can be used for decryption or encryption. The operation performed
depends on the value of the enc parameter. It should be set to 1 for encryption, 0 for
decryption and -1 to leave the value unchanged (the actual value of 'enc' being
supplied in a previous call).
EVP_CIPHER_CTX_reset()
Clears all information from a cipher context and free up any allocated memory
associated with it, except the ctx itself. This function should be called anytime ctx
is reused by another EVP_CipherInit() / EVP_CipherUpdate() / EVP_CipherFinal() series
of calls.
EVP_EncryptInit(), EVP_DecryptInit() and EVP_CipherInit()
Behave in a similar way to EVP_EncryptInit_ex(), EVP_DecryptInit_ex() and
EVP_CipherInit_ex() except if the type is not a fetched cipher they use the default
implementation of the type.
EVP_EncryptFinal(), EVP_DecryptFinal() and EVP_CipherFinal()
Identical to EVP_EncryptFinal_ex(), EVP_DecryptFinal_ex() and EVP_CipherFinal_ex(). In
previous releases they also cleaned up the ctx, but this is no longer done and
EVP_CIPHER_CTX_cleanup() must be called to free any context resources.
EVP_Cipher()
Encrypts or decrypts a maximum inl amount of bytes from in and leaves the result in
out.
For legacy ciphers - If the cipher doesn't have the flag EVP_CIPH_FLAG_CUSTOM_CIPHER
set, then inl must be a multiple of EVP_CIPHER_get_block_size(). If it isn't, the
result is undefined. If the cipher has that flag set, then inl can be any size.
Due to the constraints of the API contract of this function it shouldn't be used in
applications, please consider using EVP_CipherUpdate() and EVP_CipherFinal_ex()
instead.
EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj()
Returns an EVP_CIPHER structure when passed a cipher name, a cipher NID or an
ASN1_OBJECT structure respectively.
EVP_get_cipherbyname() will return NULL for algorithms such as "AES-128-SIV",
"AES-128-CBC-CTS" and "CAMELLIA-128-CBC-CTS" which were previously only accessible via
low level interfaces.
The EVP_get_cipherbyname() function is present for backwards compatibility with
OpenSSL prior to version 3 and is different to the EVP_CIPHER_fetch() function since
it does not attempt to "fetch" an implementation of the cipher. Additionally, it only
knows about ciphers that are built-in to OpenSSL and have an associated NID. Similarly
EVP_get_cipherbynid() and EVP_get_cipherbyobj() also return objects without an
associated implementation.
When the cipher objects returned by these functions are used (such as in a call to
EVP_EncryptInit_ex()) an implementation of the cipher will be implicitly fetched from
the loaded providers. This fetch could fail if no suitable implementation is
available. Use EVP_CIPHER_fetch() instead to explicitly fetch the algorithm and an
associated implementation from a provider.
See "ALGORITHM FETCHING" in crypto(7) for more information about fetching.
The cipher objects returned from these functions do not need to be freed with
EVP_CIPHER_free().
EVP_CIPHER_get_nid() and EVP_CIPHER_CTX_get_nid()
Return the NID of a cipher when passed an EVP_CIPHER or EVP_CIPHER_CTX structure. The
actual NID value is an internal value which may not have a corresponding OBJECT
IDENTIFIER.
EVP_CIPHER_CTX_set_flags(), EVP_CIPHER_CTX_clear_flags() and EVP_CIPHER_CTX_test_flags()
Sets, clears and tests ctx flags. See "FLAGS" below for more information.
For provided ciphers EVP_CIPHER_CTX_set_flags() should be called only after the
fetched cipher has been assigned to the ctx. It is recommended to use "PARAMETERS"
instead.
EVP_CIPHER_CTX_set_padding()
Enables or disables padding. This function should be called after the context is set
up for encryption or decryption with EVP_EncryptInit_ex2(), EVP_DecryptInit_ex2() or
EVP_CipherInit_ex2(). By default encryption operations are padded using standard block
padding and the padding is checked and removed when decrypting. If the pad parameter
is zero then no padding is performed, the total amount of data encrypted or decrypted
must then be a multiple of the block size or an error will occur.
EVP_CIPHER_get_key_length() and EVP_CIPHER_CTX_get_key_length()
Return the key length of a cipher when passed an EVP_CIPHER or EVP_CIPHER_CTX
structure. The constant EVP_MAX_KEY_LENGTH is the maximum key length for all ciphers.
Note: although EVP_CIPHER_get_key_length() is fixed for a given cipher, the value of
EVP_CIPHER_CTX_get_key_length() may be different for variable key length ciphers.
EVP_CIPHER_CTX_set_key_length()
Sets the key length of the cipher context. If the cipher is a fixed length cipher
then attempting to set the key length to any value other than the fixed value is an
error.
EVP_CIPHER_get_iv_length() and EVP_CIPHER_CTX_get_iv_length()
Return the IV length of a cipher when passed an EVP_CIPHER or EVP_CIPHER_CTX. It will
return zero if the cipher does not use an IV. The constant EVP_MAX_IV_LENGTH is the
maximum IV length for all ciphers.
EVP_CIPHER_CTX_get_tag_length()
Returns the tag length of an AEAD cipher when passed a EVP_CIPHER_CTX. It will return
zero if the cipher does not support a tag. It returns a default value if the tag
length has not been set.
EVP_CIPHER_get_block_size() and EVP_CIPHER_CTX_get_block_size()
Return the block size of a cipher when passed an EVP_CIPHER or EVP_CIPHER_CTX
structure. The constant EVP_MAX_BLOCK_LENGTH is also the maximum block length for all
ciphers.
EVP_CIPHER_get_type() and EVP_CIPHER_CTX_get_type()
Return the type of the passed cipher or context. This "type" is the actual NID of the
cipher OBJECT IDENTIFIER and as such it ignores the cipher parameters (40 bit RC2 and
128 bit RC2 have the same NID). If the cipher does not have an object identifier or
does not have ASN1 support this function will return NID_undef.
EVP_CIPHER_is_a()
Returns 1 if cipher is an implementation of an algorithm that's identifiable with
name, otherwise 0. If cipher is a legacy cipher (it's the return value from the likes
of EVP_aes128() rather than the result of an EVP_CIPHER_fetch()), only cipher names
registered with the default library context (see OSSL_LIB_CTX(3)) will be considered.
EVP_CIPHER_get0_name() and EVP_CIPHER_CTX_get0_name()
Return the name of the passed cipher or context. For fetched ciphers with multiple
names, only one of them is returned. See also EVP_CIPHER_names_do_all().
EVP_CIPHER_names_do_all()
Traverses all names for the cipher, and calls fn with each name and data. This is
only useful with fetched EVP_CIPHERs.
EVP_CIPHER_get0_description()
Returns a description of the cipher, meant for display and human consumption. The
description is at the discretion of the cipher implementation.
EVP_CIPHER_get0_provider()
Returns an OSSL_PROVIDER pointer to the provider that implements the given EVP_CIPHER.
EVP_CIPHER_CTX_get0_cipher()
Returns the EVP_CIPHER structure when passed an EVP_CIPHER_CTX structure.
EVP_CIPHER_CTX_get1_cipher() is the same except the ownership is passed to the caller.
EVP_CIPHER_get_mode() and EVP_CIPHER_CTX_get_mode()
Return the block cipher mode: EVP_CIPH_ECB_MODE, EVP_CIPH_CBC_MODE, EVP_CIPH_CFB_MODE,
EVP_CIPH_OFB_MODE, EVP_CIPH_CTR_MODE, EVP_CIPH_GCM_MODE, EVP_CIPH_CCM_MODE,
EVP_CIPH_XTS_MODE, EVP_CIPH_WRAP_MODE, EVP_CIPH_OCB_MODE or EVP_CIPH_SIV_MODE. If the
cipher is a stream cipher then EVP_CIPH_STREAM_CIPHER is returned.
EVP_CIPHER_get_flags()
Returns any flags associated with the cipher. See "FLAGS" for a list of currently
defined flags.
EVP_CIPHER_CTX_get_num() and EVP_CIPHER_CTX_set_num()
Gets or sets the cipher specific "num" parameter for the associated ctx. Built-in
ciphers typically use this to track how much of the current underlying block has been
"used" already.
EVP_CIPHER_CTX_is_encrypting()
Reports whether the ctx is being used for encryption or decryption.
EVP_CIPHER_CTX_flags()
A deprecated macro calling "EVP_CIPHER_get_flags(EVP_CIPHER_CTX_get0_cipher(ctx))".
Do not use.
EVP_CIPHER_param_to_asn1()
Sets the AlgorithmIdentifier "parameter" based on the passed cipher. This will
typically include any parameters and an IV. The cipher IV (if any) must be set when
this call is made. This call should be made before the cipher is actually "used"
(before any EVP_EncryptUpdate(), EVP_DecryptUpdate() calls for example). This
function may fail if the cipher does not have any ASN1 support.
EVP_CIPHER_asn1_to_param()
Sets the cipher parameters based on an ASN1 AlgorithmIdentifier "parameter". The
precise effect depends on the cipher. In the case of RC2, for example, it will set the
IV and effective key length. This function should be called after the base cipher
type is set but before the key is set. For example EVP_CipherInit() will be called
with the IV and key set to NULL, EVP_CIPHER_asn1_to_param() will be called and finally
EVP_CipherInit() again with all parameters except the key set to NULL. It is possible
for this function to fail if the cipher does not have any ASN1 support or the
parameters cannot be set (for example the RC2 effective key length is not supported.
EVP_CIPHER_CTX_rand_key()
Generates a random key of the appropriate length based on the cipher context. The
EVP_CIPHER can provide its own random key generation routine to support keys of a
specific form. key must point to a buffer at least as big as the value returned by
EVP_CIPHER_CTX_get_key_length().
EVP_CIPHER_do_all_provided()
Traverses all ciphers implemented by all activated providers in the given library
context libctx, and for each of the implementations, calls the given function fn with
the implementation method and the given arg as argument.
PARAMETERS
See OSSL_PARAM(3) for information about passing parameters.
Gettable EVP_CIPHER parameters
When EVP_CIPHER_fetch() is called it internally calls EVP_CIPHER_get_params() and caches
the results.
EVP_CIPHER_get_params() can be used with the following OSSL_PARAM keys:
"mode" (OSSL_CIPHER_PARAM_MODE) <unsigned integer>
Gets the mode for the associated cipher algorithm cipher. See "EVP_CIPHER_get_mode()
and EVP_CIPHER_CTX_get_mode()" for a list of valid modes. Use EVP_CIPHER_get_mode()
to retrieve the cached value.
"keylen" (OSSL_CIPHER_PARAM_KEYLEN) <unsigned integer>
Gets the key length for the associated cipher algorithm cipher. Use
EVP_CIPHER_get_key_length() to retrieve the cached value.
"ivlen" (OSSL_CIPHER_PARAM_IVLEN) <unsigned integer>
Gets the IV length for the associated cipher algorithm cipher. Use
EVP_CIPHER_get_iv_length() to retrieve the cached value.
"blocksize" (OSSL_CIPHER_PARAM_BLOCK_SIZE) <unsigned integer>
Gets the block size for the associated cipher algorithm cipher. The block size should
be 1 for stream ciphers. Note that the block size for a cipher may be different to
the block size for the underlying encryption/decryption primitive. For example AES in
CTR mode has a block size of 1 (because it operates like a stream cipher), even though
AES has a block size of 16. Use EVP_CIPHER_get_block_size() to retreive the cached
value.
"aead" (OSSL_CIPHER_PARAM_AEAD) <integer>
Gets 1 if this is an AEAD cipher algorithm, otherwise it gets 0. Use
(EVP_CIPHER_get_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER) to retrieve the cached
value.
"custom-iv" (OSSL_CIPHER_PARAM_CUSTOM_IV) <integer>
Gets 1 if the cipher algorithm cipher has a custom IV, otherwise it gets 0. Storing
and initializing the IV is left entirely to the implementation, if a custom IV is
used. Use (EVP_CIPHER_get_flags(cipher) & EVP_CIPH_CUSTOM_IV) to retrieve the cached
value.
"cts" (OSSL_CIPHER_PARAM_CTS) <integer>
Gets 1 if the cipher algorithm cipher uses ciphertext stealing, otherwise it gets 0.
This is currently used to indicate that the cipher is a one shot that only allows a
single call to EVP_CipherUpdate(). Use (EVP_CIPHER_get_flags(cipher) &
EVP_CIPH_FLAG_CTS) to retrieve the cached value.
"tls-multi" (OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK) <integer>
Gets 1 if the cipher algorithm cipher supports interleaving of crypto blocks,
otherwise it gets 0. The interleaving is an optimization only applicable to certain
TLS ciphers. Use (EVP_CIPHER_get_flags(cipher) & EVP_CIPH_FLAG_TLS1_1_MULTIBLOCK) to
retrieve the cached value.
"has-randkey" (OSSL_CIPHER_PARAM_HAS_RANDKEY) <integer>
Gets 1 if the cipher algorithm cipher supports the gettable EVP_CIPHER_CTX parameter
OSSL_CIPHER_PARAM_RANDOM_KEY. Only DES and 3DES set this to 1, all other OpenSSL
ciphers return 0.
Gettable and Settable EVP_CIPHER_CTX parameters
The following OSSL_PARAM keys can be used with both EVP_CIPHER_CTX_get_params() and
EVP_CIPHER_CTX_set_params().
"padding" (OSSL_CIPHER_PARAM_PADDING) <unsigned integer>
Gets or sets the padding mode for the cipher context ctx. Padding is enabled if the
value is 1, and disabled if the value is 0. See also EVP_CIPHER_CTX_set_padding().
"num" (OSSL_CIPHER_PARAM_NUM) <unsigned integer>
Gets or sets the cipher specific "num" parameter for the cipher context ctx. Built-in
ciphers typically use this to track how much of the current underlying block has been
"used" already. See also EVP_CIPHER_CTX_get_num() and EVP_CIPHER_CTX_set_num().
"keylen" (OSSL_CIPHER_PARAM_KEYLEN) <unsigned integer>
Gets or sets the key length for the cipher context ctx. The length of the "keylen"
parameter should not exceed that of a size_t. See also
EVP_CIPHER_CTX_get_key_length() and EVP_CIPHER_CTX_set_key_length().
"tag" (OSSL_CIPHER_PARAM_AEAD_TAG) <octet string>
Gets or sets the AEAD tag for the associated cipher context ctx. See "AEAD Interface"
in EVP_EncryptInit(3).
"keybits" (OSSL_CIPHER_PARAM_RC2_KEYBITS) <unsigned integer>
Gets or sets the effective keybits used for a RC2 cipher. The length of the "keybits"
parameter should not exceed that of a size_t.
"rounds" (OSSL_CIPHER_PARAM_ROUNDS) <unsigned integer>
Gets or sets the number of rounds to be used for a cipher. This is used by the RC5
cipher.
"alg_id_param" (OSSL_CIPHER_PARAM_ALGORITHM_ID_PARAMS) <octet string>
Used to pass the DER encoded AlgorithmIdentifier parameter to or from the cipher
implementation. Functions like EVP_CIPHER_param_to_asn1(3) and
EVP_CIPHER_asn1_to_param(3) use this parameter for any implementation that has the
flag EVP_CIPH_FLAG_CUSTOM_ASN1 set.
"cts_mode" (OSSL_CIPHER_PARAM_CTS_MODE) <UTF8 string>
Gets or sets the cipher text stealing mode. For all modes the output size is the same
as the input size. The input length must be greater than or equal to the block size.
(The block size for AES and CAMELLIA is 16 bytes).
Valid values for the mode are:
"CS1"
The NIST variant of cipher text stealing. For input lengths that are multiples of
the block size it is equivalent to using a "AES-XXX-CBC" or "CAMELLIA-XXX-CBC"
cipher otherwise the second last cipher text block is a partial block.
"CS2"
For input lengths that are multiples of the block size it is equivalent to using a
"AES-XXX-CBC" or "CAMELLIA-XXX-CBC" cipher, otherwise it is the same as "CS3"
mode.
"CS3"
The Kerberos5 variant of cipher text stealing which always swaps the last cipher
text block with the previous block (which may be a partial or full block depending
on the input length). If the input length is exactly one full block then this is
equivalent to using a "AES-XXX-CBC" or "CAMELLIA-XXX-CBC" cipher.
The default is "CS1". This is only supported for "AES-128-CBC-CTS",
"AES-192-CBC-CTS", "AES-256-CBC-CTS", "CAMELLIA-128-CBC-CTS", "CAMELLIA-192-CBC-CTS"
and "CAMELLIA-256-CBC-CTS".
"tls1multi_interleave" (OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_INTERLEAVE) <unsigned integer>
Sets or gets the number of records being sent in one go for a tls1 multiblock cipher
operation (either 4 or 8 records).
Gettable EVP_CIPHER_CTX parameters
The following OSSL_PARAM keys can be used with EVP_CIPHER_CTX_get_params():
"ivlen" (OSSL_CIPHER_PARAM_IVLEN and <OSSL_CIPHER_PARAM_AEAD_IVLEN) <unsigned integer>
Gets the IV length for the cipher context ctx. The length of the "ivlen" parameter
should not exceed that of a size_t. See also EVP_CIPHER_CTX_get_iv_length().
"iv" (OSSL_CIPHER_PARAM_IV) <octet string OR octet ptr>
Gets the IV used to initialize the associated cipher context ctx. See also
EVP_CIPHER_CTX_get_original_iv().
"updated-iv" (OSSL_CIPHER_PARAM_UPDATED_IV) <octet string OR octet ptr>
Gets the updated pseudo-IV state for the associated cipher context, e.g., the previous
ciphertext block for CBC mode or the iteratively encrypted IV value for OFB mode.
Note that octet pointer access is deprecated and is provided only for backwards
compatibility with historical libcrypto APIs. See also
EVP_CIPHER_CTX_get_updated_iv().
"randkey" (OSSL_CIPHER_PARAM_RANDOM_KEY) <octet string>
Gets an implementation specific randomly generated key for the associated cipher
context ctx. This is currently only supported by DES and 3DES (which set the key to
odd parity).
"taglen" (OSSL_CIPHER_PARAM_AEAD_TAGLEN) <unsigned integer>
Gets the tag length to be used for an AEAD cipher for the associated cipher context
ctx. It gets a default value if it has not been set. The length of the "taglen"
parameter should not exceed that of a size_t. See also
EVP_CIPHER_CTX_get_tag_length().
"tlsaadpad" (OSSL_CIPHER_PARAM_AEAD_TLS1_AAD_PAD) <unsigned integer>
Gets the length of the tag that will be added to a TLS record for the AEAD tag for the
associated cipher context ctx. The length of the "tlsaadpad" parameter should not
exceed that of a size_t.
"tlsivgen" (OSSL_CIPHER_PARAM_AEAD_TLS1_GET_IV_GEN) <octet string>
Gets the invocation field generated for encryption. Can only be called after
"tlsivfixed" is set. This is only used for GCM mode.
"tls1multi_enclen" (OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC_LEN) <unsigned integer>
Get the total length of the record returned from the "tls1multi_enc" operation.
"tls1multi_maxbufsz" (OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_MAX_BUFSIZE) <unsigned integer>
Gets the maximum record length for a TLS1 multiblock cipher operation. The length of
the "tls1multi_maxbufsz" parameter should not exceed that of a size_t.
"tls1multi_aadpacklen" (OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_AAD_PACKLEN) <unsigned integer>
Gets the result of running the "tls1multi_aad" operation.
"tls-mac" (OSSL_CIPHER_PARAM_TLS_MAC) <octet ptr>
Used to pass the TLS MAC data.
Settable EVP_CIPHER_CTX parameters
The following OSSL_PARAM keys can be used with EVP_CIPHER_CTX_set_params():
"mackey" (OSSL_CIPHER_PARAM_AEAD_MAC_KEY) <octet string>
Sets the MAC key used by composite AEAD ciphers such as AES-CBC-HMAC-SHA256.
"speed" (OSSL_CIPHER_PARAM_SPEED) <unsigned integer>
Sets the speed option for the associated cipher context. This is only supported by AES
SIV ciphers which disallow multiple operations by default. Setting "speed" to 1
allows another encrypt or decrypt operation to be performed. This is used for
performance testing.
"use-bits" (OSSL_CIPHER_PARAM_USE_BITS) <unsigned integer>
Determines if the input length inl passed to EVP_EncryptUpdate(), EVP_DecryptUpdate()
and EVP_CipherUpdate() is the number of bits or number of bytes. Setting "use-bits"
to 1 uses bits. The default is in bytes. This is only used for CFB1 ciphers.
This can be set using EVP_CIPHER_CTX_set_flags(ctx, EVP_CIPH_FLAG_LENGTH_BITS).
"tls-version" (OSSL_CIPHER_PARAM_TLS_VERSION) <integer>
Sets the TLS version.
"tls-mac-size" (OSSL_CIPHER_PARAM_TLS_MAC_SIZE) <unsigned integer>
Set the TLS MAC size.
"tlsaad" (OSSL_CIPHER_PARAM_AEAD_TLS1_AAD) <octet string>
Sets TLSv1.2 AAD information for the associated cipher context ctx. TLSv1.2 AAD
information is always 13 bytes in length and is as defined for the "additional_data"
field described in section 6.2.3.3 of RFC5246.
"tlsivfixed" (OSSL_CIPHER_PARAM_AEAD_TLS1_IV_FIXED) <octet string>
Sets the fixed portion of an IV for an AEAD cipher used in a TLS record encryption/
decryption for the associated cipher context. TLS record encryption/decryption always
occurs "in place" so that the input and output buffers are always the same memory
location. AEAD IVs in TLSv1.2 consist of an implicit "fixed" part and an explicit
part that varies with every record. Setting a TLS fixed IV changes a cipher to
encrypt/decrypt TLS records. TLS records are encrypted/decrypted using a single
OSSL_FUNC_cipher_cipher call per record. For a record decryption the first bytes of
the input buffer will be the explicit part of the IV and the final bytes of the input
buffer will be the AEAD tag. The length of the explicit part of the IV and the tag
length will depend on the cipher in use and will be defined in the RFC for the
relevant ciphersuite. In order to allow for "in place" decryption the plaintext
output should be written to the same location in the output buffer that the ciphertext
payload was read from, i.e. immediately after the explicit IV.
When encrypting a record the first bytes of the input buffer should be empty to allow
space for the explicit IV, as will the final bytes where the tag will be written. The
length of the input buffer will include the length of the explicit IV, the payload,
and the tag bytes. The cipher implementation should generate the explicit IV and
write it to the beginning of the output buffer, do "in place" encryption of the
payload and write that to the output buffer, and finally add the tag onto the end of
the output buffer.
Whether encrypting or decrypting the value written to *outl in the
OSSL_FUNC_cipher_cipher call should be the length of the payload excluding the
explicit IV length and the tag length.
"tlsivinv" (OSSL_CIPHER_PARAM_AEAD_TLS1_SET_IV_INV) <octet string>
Sets the invocation field used for decryption. Can only be called after "tlsivfixed"
is set. This is only used for GCM mode.
"tls1multi_enc" (OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC) <octet string>
Triggers a multiblock TLS1 encrypt operation for a TLS1 aware cipher that supports
sending 4 or 8 records in one go. The cipher performs both the MAC and encrypt stages
and constructs the record headers itself. "tls1multi_enc" supplies the output buffer
for the encrypt operation, "tls1multi_encin" & "tls1multi_interleave" must also be set
in order to supply values to the encrypt operation.
"tls1multi_encin" (OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC_IN) <octet string>
Supplies the data to encrypt for a TLS1 multiblock cipher operation.
"tls1multi_maxsndfrag" (OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_MAX_SEND_FRAGMENT) <unsigned
integer>
Sets the maximum send fragment size for a TLS1 multiblock cipher operation. It must
be set before using "tls1multi_maxbufsz". The length of the "tls1multi_maxsndfrag"
parameter should not exceed that of a size_t.
"tls1multi_aad" (OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_AAD) <octet string>
Sets the authenticated additional data used by a TLS1 multiblock cipher operation.
The supplied data consists of 13 bytes of record data containing: Bytes 0-7: The
sequence number of the first record Byte 8: The record type Byte 9-10: The protocol
version Byte 11-12: Input length (Always 0)
"tls1multi_interleave" must also be set for this operation.
CONTROLS
The Mappings from EVP_CIPHER_CTX_ctrl() identifiers to PARAMETERS are listed in the
following section. See the "PARAMETERS" section for more details.
EVP_CIPHER_CTX_ctrl() can be used to send the following standard controls:
EVP_CTRL_AEAD_SET_IVLEN and EVP_CTRL_GET_IVLEN
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_set_params() and
EVP_CIPHER_CTX_get_params() get called with an OSSL_PARAM(3) item with the key "ivlen"
(OSSL_CIPHER_PARAM_IVLEN).
EVP_CTRL_AEAD_SET_IV_FIXED
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_set_params() gets called with an
OSSL_PARAM(3) item with the key "tlsivfixed" (OSSL_CIPHER_PARAM_AEAD_TLS1_IV_FIXED).
EVP_CTRL_AEAD_SET_MAC_KEY
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_set_params() gets called with an
OSSL_PARAM(3) item with the key "mackey" (OSSL_CIPHER_PARAM_AEAD_MAC_KEY).
EVP_CTRL_AEAD_SET_TAG and EVP_CTRL_AEAD_GET_TAG
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_set_params() and
EVP_CIPHER_CTX_get_params() get called with an OSSL_PARAM(3) item with the key "tag"
(OSSL_CIPHER_PARAM_AEAD_TAG).
EVP_CTRL_CCM_SET_L
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_set_params() gets called with an
OSSL_PARAM(3) item with the key "ivlen" (OSSL_CIPHER_PARAM_IVLEN) with a value of (15
- L)
EVP_CTRL_COPY
There is no OSSL_PARAM mapping for this. Use EVP_CIPHER_CTX_copy() instead.
EVP_CTRL_GCM_SET_IV_INV
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_set_params() gets called with an
OSSL_PARAM(3) item with the key "tlsivinv" (OSSL_CIPHER_PARAM_AEAD_TLS1_SET_IV_INV).
EVP_CTRL_RAND_KEY
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_set_params() gets called with an
OSSL_PARAM(3) item with the key "randkey" (OSSL_CIPHER_PARAM_RANDOM_KEY).
EVP_CTRL_SET_KEY_LENGTH
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_set_params() gets called with an
OSSL_PARAM(3) item with the key "keylen" (OSSL_CIPHER_PARAM_KEYLEN).
EVP_CTRL_SET_RC2_KEY_BITS and EVP_CTRL_GET_RC2_KEY_BITS
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_set_params() and
EVP_CIPHER_CTX_get_params() get called with an OSSL_PARAM(3) item with the key
"keybits" (OSSL_CIPHER_PARAM_RC2_KEYBITS).
EVP_CTRL_SET_RC5_ROUNDS and EVP_CTRL_GET_RC5_ROUNDS
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_set_params() and
EVP_CIPHER_CTX_get_params() get called with an OSSL_PARAM(3) item with the key
"rounds" (OSSL_CIPHER_PARAM_ROUNDS).
EVP_CTRL_SET_SPEED
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_set_params() gets called with an
OSSL_PARAM(3) item with the key "speed" (OSSL_CIPHER_PARAM_SPEED).
EVP_CTRL_GCM_IV_GEN
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_get_params() gets called with an
OSSL_PARAM(3) item with the key "tlsivgen" (OSSL_CIPHER_PARAM_AEAD_TLS1_GET_IV_GEN).
EVP_CTRL_AEAD_TLS1_AAD
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_set_params() get called with an
OSSL_PARAM(3) item with the key "tlsaadpad" (OSSL_CIPHER_PARAM_AEAD_TLS1_AAD) followed
by EVP_CIPHER_CTX_get_params() with a key of "tlsaadpad"
(OSSL_CIPHER_PARAM_AEAD_TLS1_AAD_PAD).
EVP_CTRL_TLS1_1_MULTIBLOCK_MAX_BUFSIZE
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_set_params() gets called with an
OSSL_PARAM(3) item with the key OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_MAX_SEND_FRAGMENT
followed by EVP_CIPHER_CTX_get_params() with a key of "tls1multi_maxbufsz"
(OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_MAX_BUFSIZE).
EVP_CTRL_TLS1_1_MULTIBLOCK_AAD
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_set_params() gets called with
OSSL_PARAM(3) items with the keys "tls1multi_aad"
(OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_AAD) and "tls1multi_interleave"
(OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_INTERLEAVE) followed by EVP_CIPHER_CTX_get_params()
with keys of "tls1multi_aadpacklen" (OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_AAD_PACKLEN)
and "tls1multi_interleave" (OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_INTERLEAVE).
EVP_CTRL_TLS1_1_MULTIBLOCK_ENCRYPT
When used with a fetched EVP_CIPHER, EVP_CIPHER_CTX_set_params() gets called with
OSSL_PARAM(3) items with the keys "tls1multi_enc"
(OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC), "tls1multi_encin"
(OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC_IN) and "tls1multi_interleave"
(OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_INTERLEAVE), followed by
EVP_CIPHER_CTX_get_params() with a key of "tls1multi_enclen"
(OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC_LEN).
FLAGS
EVP_CIPHER_CTX_set_flags(), EVP_CIPHER_CTX_clear_flags() and EVP_CIPHER_CTX_test_flags().
can be used to manipulate and test these EVP_CIPHER_CTX flags:
EVP_CIPH_NO_PADDING
Used by EVP_CIPHER_CTX_set_padding().
See also "Gettable and Settable EVP_CIPHER_CTX parameters" "padding"
EVP_CIPH_FLAG_LENGTH_BITS
See "Settable EVP_CIPHER_CTX parameters" "use-bits".
EVP_CIPHER_CTX_FLAG_WRAP_ALLOW
Used for Legacy purposes only. This flag needed to be set to indicate the cipher
handled wrapping.
EVP_CIPHER_flags() uses the following flags that have mappings to "Gettable EVP_CIPHER
parameters":
EVP_CIPH_FLAG_AEAD_CIPHER
See "Gettable EVP_CIPHER parameters" "aead".
EVP_CIPH_CUSTOM_IV
See "Gettable EVP_CIPHER parameters" "custom-iv".
EVP_CIPH_FLAG_CTS
See "Gettable EVP_CIPHER parameters" "cts".
EVP_CIPH_FLAG_TLS1_1_MULTIBLOCK;
See "Gettable EVP_CIPHER parameters" "tls-multi".
EVP_CIPH_RAND_KEY
See "Gettable EVP_CIPHER parameters" "has-randkey".
EVP_CIPHER_flags() uses the following flags for legacy purposes only:
EVP_CIPH_VARIABLE_LENGTH
EVP_CIPH_FLAG_CUSTOM_CIPHER
EVP_CIPH_ALWAYS_CALL_INIT
EVP_CIPH_CTRL_INIT
EVP_CIPH_CUSTOM_KEY_LENGTH
EVP_CIPH_CUSTOM_COPY
EVP_CIPH_FLAG_DEFAULT_ASN1
See EVP_CIPHER_meth_set_flags(3) for further information related to the above flags.
RETURN VALUES
EVP_CIPHER_fetch() returns a pointer to a EVP_CIPHER for success and NULL for failure.
EVP_CIPHER_up_ref() returns 1 for success or 0 otherwise.
EVP_CIPHER_CTX_new() returns a pointer to a newly created EVP_CIPHER_CTX for success and
NULL for failure.
EVP_EncryptInit_ex2(), EVP_EncryptUpdate() and EVP_EncryptFinal_ex() return 1 for success
and 0 for failure.
EVP_DecryptInit_ex2() and EVP_DecryptUpdate() return 1 for success and 0 for failure.
EVP_DecryptFinal_ex() returns 0 if the decrypt failed or 1 for success.
EVP_CipherInit_ex2() and EVP_CipherUpdate() return 1 for success and 0 for failure.
EVP_CipherFinal_ex() returns 0 for a decryption failure or 1 for success.
EVP_Cipher() returns the amount of encrypted / decrypted bytes, or -1 on failure if the
flag EVP_CIPH_FLAG_CUSTOM_CIPHER is set for the cipher. EVP_Cipher() returns 1 on success
or 0 on failure, if the flag EVP_CIPH_FLAG_CUSTOM_CIPHER is not set for the cipher.
EVP_CIPHER_CTX_reset() returns 1 for success and 0 for failure.
EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj() return an
EVP_CIPHER structure or NULL on error.
EVP_CIPHER_get_nid() and EVP_CIPHER_CTX_get_nid() return a NID.
EVP_CIPHER_get_block_size() and EVP_CIPHER_CTX_get_block_size() return the block size.
EVP_CIPHER_get_key_length() and EVP_CIPHER_CTX_get_key_length() return the key length.
EVP_CIPHER_CTX_set_padding() always returns 1.
EVP_CIPHER_get_iv_length() and EVP_CIPHER_CTX_get_iv_length() return the IV length or zero
if the cipher does not use an IV.
EVP_CIPHER_CTX_get_tag_length() return the tag length or zero if the cipher does not use a
tag.
EVP_CIPHER_get_type() and EVP_CIPHER_CTX_get_type() return the NID of the cipher's OBJECT
IDENTIFIER or NID_undef if it has no defined OBJECT IDENTIFIER.
EVP_CIPHER_CTX_cipher() returns an EVP_CIPHER structure.
EVP_CIPHER_CTX_get_num() returns a nonnegative num value or EVP_CTRL_RET_UNSUPPORTED if
the implementation does not support the call or on any other error.
EVP_CIPHER_CTX_set_num() returns 1 on success and 0 if the implementation does not support
the call or on any other error.
EVP_CIPHER_CTX_is_encrypting() returns 1 if the ctx is set up for encryption 0 otherwise.
EVP_CIPHER_param_to_asn1() and EVP_CIPHER_asn1_to_param() return greater than zero for
success and zero or a negative number on failure.
EVP_CIPHER_CTX_rand_key() returns 1 for success.
EVP_CIPHER_names_do_all() returns 1 if the callback was called for all names. A return
value of 0 means that the callback was not called for any names.
CIPHER LISTING
All algorithms have a fixed key length unless otherwise stated.
Refer to "SEE ALSO" for the full list of ciphers available through the EVP interface.
EVP_enc_null()
Null cipher: does nothing.
AEAD INTERFACE
The EVP interface for Authenticated Encryption with Associated Data (AEAD) modes are
subtly altered and several additional ctrl operations are supported depending on the mode
specified.
To specify additional authenticated data (AAD), a call to EVP_CipherUpdate(),
EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made with the output parameter out
set to NULL.
When decrypting, the return value of EVP_DecryptFinal() or EVP_CipherFinal() indicates
whether the operation was successful. If it does not indicate success, the authentication
operation has failed and any output data MUST NOT be used as it is corrupted.
GCM and OCB Modes
The following ctrls are supported in GCM and OCB modes.
EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
Sets the IV length. This call can only be made before specifying an IV. If not called
a default IV length is used.
For GCM AES and OCB AES the default is 12 (i.e. 96 bits). For OCB mode the maximum is
15.
EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag)
Writes "taglen" bytes of the tag value to the buffer indicated by "tag". This call
can only be made when encrypting data and after all data has been processed (e.g.
after an EVP_EncryptFinal() call).
For OCB, "taglen" must either be 16 or the value previously set via
EVP_CTRL_AEAD_SET_TAG.
EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag)
When decrypting, this call sets the expected tag to "taglen" bytes from "tag".
"taglen" must be between 1 and 16 inclusive. The tag must be set prior to any call to
EVP_DecryptFinal() or EVP_DecryptFinal_ex().
For GCM, this call is only valid when decrypting data.
For OCB, this call is valid when decrypting data to set the expected tag, and when
encrypting to set the desired tag length.
In OCB mode, calling this when encrypting with "tag" set to "NULL" sets the tag
length. The tag length can only be set before specifying an IV. If this is not called
prior to setting the IV during encryption, then a default tag length is used.
For OCB AES, the default tag length is 16 (i.e. 128 bits). It is also the maximum tag
length for OCB.
CCM Mode
The EVP interface for CCM mode is similar to that of the GCM mode but with a few
additional requirements and different ctrl values.
For CCM mode, the total plaintext or ciphertext length MUST be passed to
EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() with the output and input
parameters (in and out) set to NULL and the length passed in the inl parameter.
The following ctrls are supported in CCM mode.
EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag)
This call is made to set the expected CCM tag value when decrypting or the length of
the tag (with the "tag" parameter set to NULL) when encrypting. The tag length is
often referred to as M. If not set a default value is used (12 for AES). When
decrypting, the tag needs to be set before passing in data to be decrypted, but as in
GCM and OCB mode, it can be set after passing additional authenticated data (see "AEAD
INTERFACE").
EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_CCM_SET_L, ivlen, NULL)
Sets the CCM L value. If not set a default is used (8 for AES).
EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
Sets the CCM nonce (IV) length. This call can only be made before specifying a nonce
value. The nonce length is given by 15 - L so it is 7 by default for AES.
SIV Mode
For SIV mode ciphers the behaviour of the EVP interface is subtly altered and several
additional ctrl operations are supported.
To specify any additional authenticated data (AAD) and/or a Nonce, a call to
EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made with the
output parameter out set to NULL.
RFC5297 states that the Nonce is the last piece of AAD before the actual encrypt/decrypt
takes place. The API does not differentiate the Nonce from other AAD.
When decrypting the return value of EVP_DecryptFinal() or EVP_CipherFinal() indicates if
the operation was successful. If it does not indicate success the authentication operation
has failed and any output data MUST NOT be used as it is corrupted.
The API does not store the the SIV (Synthetic Initialization Vector) in the cipher text.
Instead, it is stored as the tag within the EVP_CIPHER_CTX. The SIV must be retrieved
from the context after encryption, and set into the context before decryption.
This differs from RFC5297 in that the cipher output from encryption, and the cipher input
to decryption, does not contain the SIV. This also means that the plain text and cipher
text lengths are identical.
The following ctrls are supported in SIV mode, and are used to get and set the Synthetic
Initialization Vector:
EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag);
Writes taglen bytes of the tag value (the Synthetic Initialization Vector) to the
buffer indicated by tag. This call can only be made when encrypting data and after all
data has been processed (e.g. after an EVP_EncryptFinal() call). For SIV mode the
taglen must be 16.
EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag);
Sets the expected tag (the Synthetic Initialization Vector) to taglen bytes from tag.
This call is only legal when decrypting data and must be made before any data is
processed (e.g. before any EVP_DecryptUpdate() calls). For SIV mode the taglen must be
16.
SIV mode makes two passes over the input data, thus, only one call to EVP_CipherUpdate(),
EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made with out set to a non-NULL
value. A call to EVP_DecryptFinal() or EVP_CipherFinal() is not required, but will
indicate if the update operation succeeded.
ChaCha20-Poly1305
The following ctrls are supported for the ChaCha20-Poly1305 AEAD algorithm.
EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
Sets the nonce length. This call can only be made before specifying the nonce. If not
called a default nonce length of 12 (i.e. 96 bits) is used. The maximum nonce length
is 12 bytes (i.e. 96-bits). If a nonce of less than 12 bytes is set then the nonce is
automatically padded with leading 0 bytes to make it 12 bytes in length.
EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag)
Writes "taglen" bytes of the tag value to the buffer indicated by "tag". This call
can only be made when encrypting data and after all data has been processed (e.g.
after an EVP_EncryptFinal() call).
"taglen" specified here must be 16 (POLY1305_BLOCK_SIZE, i.e. 128-bits) or less.
EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag)
Sets the expected tag to "taglen" bytes from "tag". The tag length can only be set
before specifying an IV. "taglen" must be between 1 and 16 (POLY1305_BLOCK_SIZE)
inclusive. This call is only valid when decrypting data.
NOTES
Where possible the EVP interface to symmetric ciphers should be used in preference to the
low-level interfaces. This is because the code then becomes transparent to the cipher used
and much more flexible. Additionally, the EVP interface will ensure the use of platform
specific cryptographic acceleration such as AES-NI (the low-level interfaces do not
provide the guarantee).
PKCS padding works by adding n padding bytes of value n to make the total length of the
encrypted data a multiple of the block size. Padding is always added so if the data is
already a multiple of the block size n will equal the block size. For example if the block
size is 8 and 11 bytes are to be encrypted then 5 padding bytes of value 5 will be added.
When decrypting the final block is checked to see if it has the correct form.
Although the decryption operation can produce an error if padding is enabled, it is not a
strong test that the input data or key is correct. A random block has better than 1 in 256
chance of being of the correct format and problems with the input data earlier on will not
produce a final decrypt error.
If padding is disabled then the decryption operation will always succeed if the total
amount of data decrypted is a multiple of the block size.
The functions EVP_EncryptInit(), EVP_EncryptInit_ex(), EVP_EncryptFinal(),
EVP_DecryptInit(), EVP_DecryptInit_ex(), EVP_CipherInit(), EVP_CipherInit_ex() and
EVP_CipherFinal() are obsolete but are retained for compatibility with existing code. New
code should use EVP_EncryptInit_ex2(), EVP_EncryptFinal_ex(), EVP_DecryptInit_ex2(),
EVP_DecryptFinal_ex(), EVP_CipherInit_ex2() and EVP_CipherFinal_ex() because they can
reuse an existing context without allocating and freeing it up on each call.
There are some differences between functions EVP_CipherInit() and EVP_CipherInit_ex(),
significant in some circumstances. EVP_CipherInit() fills the passed context object with
zeros. As a consequence, EVP_CipherInit() does not allow step-by-step initialization of
the ctx when the key and iv are passed in separate calls. It also means that the flags set
for the CTX are removed, and it is especially important for the
EVP_CIPHER_CTX_FLAG_WRAP_ALLOW flag treated specially in EVP_CipherInit_ex().
EVP_get_cipherbynid(), and EVP_get_cipherbyobj() are implemented as macros.
BUGS
EVP_MAX_KEY_LENGTH and EVP_MAX_IV_LENGTH only refer to the internal ciphers with default
key lengths. If custom ciphers exceed these values the results are unpredictable. This is
because it has become standard practice to define a generic key as a fixed unsigned char
array containing EVP_MAX_KEY_LENGTH bytes.
The ASN1 code is incomplete (and sometimes inaccurate) it has only been tested for certain
common S/MIME ciphers (RC2, DES, triple DES) in CBC mode.
EXAMPLES
Encrypt a string using IDEA:
int do_crypt(char *outfile)
{
unsigned char outbuf[1024];
int outlen, tmplen;
/*
* Bogus key and IV: we'd normally set these from
* another source.
*/
unsigned char key[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
unsigned char iv[] = {1,2,3,4,5,6,7,8};
char intext[] = "Some Crypto Text";
EVP_CIPHER_CTX *ctx;
FILE *out;
ctx = EVP_CIPHER_CTX_new();
EVP_EncryptInit_ex2(ctx, EVP_idea_cbc(), key, iv, NULL);
if (!EVP_EncryptUpdate(ctx, outbuf, &outlen, intext, strlen(intext))) {
/* Error */
EVP_CIPHER_CTX_free(ctx);
return 0;
}
/*
* Buffer passed to EVP_EncryptFinal() must be after data just
* encrypted to avoid overwriting it.
*/
if (!EVP_EncryptFinal_ex(ctx, outbuf + outlen, &tmplen)) {
/* Error */
EVP_CIPHER_CTX_free(ctx);
return 0;
}
outlen += tmplen;
EVP_CIPHER_CTX_free(ctx);
/*
* Need binary mode for fopen because encrypted data is
* binary data. Also cannot use strlen() on it because
* it won't be NUL terminated and may contain embedded
* NULs.
*/
out = fopen(outfile, "wb");
if (out == NULL) {
/* Error */
return 0;
}
fwrite(outbuf, 1, outlen, out);
fclose(out);
return 1;
}
The ciphertext from the above example can be decrypted using the openssl utility with the
command line (shown on two lines for clarity):
openssl idea -d \
-K 000102030405060708090A0B0C0D0E0F -iv 0102030405060708 <filename
General encryption and decryption function example using FILE I/O and AES128 with a
128-bit key:
int do_crypt(FILE *in, FILE *out, int do_encrypt)
{
/* Allow enough space in output buffer for additional block */
unsigned char inbuf[1024], outbuf[1024 + EVP_MAX_BLOCK_LENGTH];
int inlen, outlen;
EVP_CIPHER_CTX *ctx;
/*
* Bogus key and IV: we'd normally set these from
* another source.
*/
unsigned char key[] = "0123456789abcdeF";
unsigned char iv[] = "1234567887654321";
/* Don't set key or IV right away; we want to check lengths */
ctx = EVP_CIPHER_CTX_new();
EVP_CipherInit_ex2(ctx, EVP_aes_128_cbc(), NULL, NULL,
do_encrypt, NULL);
OPENSSL_assert(EVP_CIPHER_CTX_get_key_length(ctx) == 16);
OPENSSL_assert(EVP_CIPHER_CTX_get_iv_length(ctx) == 16);
/* Now we can set key and IV */
EVP_CipherInit_ex2(ctx, NULL, key, iv, do_encrypt, NULL);
for (;;) {
inlen = fread(inbuf, 1, 1024, in);
if (inlen <= 0)
break;
if (!EVP_CipherUpdate(ctx, outbuf, &outlen, inbuf, inlen)) {
/* Error */
EVP_CIPHER_CTX_free(ctx);
return 0;
}
fwrite(outbuf, 1, outlen, out);
}
if (!EVP_CipherFinal_ex(ctx, outbuf, &outlen)) {
/* Error */
EVP_CIPHER_CTX_free(ctx);
return 0;
}
fwrite(outbuf, 1, outlen, out);
EVP_CIPHER_CTX_free(ctx);
return 1;
}
Encryption using AES-CBC with a 256-bit key with "CS1" ciphertext stealing.
int encrypt(const unsigned char *key, const unsigned char *iv,
const unsigned char *msg, size_t msg_len, unsigned char *out)
{
/*
* This assumes that key size is 32 bytes and the iv is 16 bytes.
* For ciphertext stealing mode the length of the ciphertext "out" will be
* the same size as the plaintext size "msg_len".
* The "msg_len" can be any size >= 16.
*/
int ret = 0, encrypt = 1, outlen, len;
EVP_CIPHER_CTX *ctx = NULL;
EVP_CIPHER *cipher = NULL;
OSSL_PARAM params[2];
ctx = EVP_CIPHER_CTX_new();
cipher = EVP_CIPHER_fetch(NULL, "AES-256-CBC-CTS", NULL);
if (ctx == NULL || cipher == NULL)
goto err;
/*
* The default is "CS1" so this is not really needed,
* but would be needed to set either "CS2" or "CS3".
*/
params[0] = OSSL_PARAM_construct_utf8_string(OSSL_CIPHER_PARAM_CTS_MODE,
"CS1", 0);
params[1] = OSSL_PARAM_construct_end();
if (!EVP_CipherInit_ex2(ctx, cipher, key, iv, encrypt, params))
goto err;
/* NOTE: CTS mode does not support multiple calls to EVP_CipherUpdate() */
if (!EVP_CipherUpdate(ctx, encrypted, &outlen, msg, msglen))
goto err;
if (!EVP_CipherFinal_ex(ctx, encrypted + outlen, &len))
goto err;
ret = 1;
err:
EVP_CIPHER_free(cipher);
EVP_CIPHER_CTX_free(ctx);
return ret;
}
SEE ALSO
evp(7), property(7), "ALGORITHM FETCHING" in crypto(7), provider-cipher(7),
life_cycle-cipher(7)
Supported ciphers are listed in:
EVP_aes_128_gcm(3), EVP_aria_128_gcm(3), EVP_bf_cbc(3), EVP_camellia_128_ecb(3),
EVP_cast5_cbc(3), EVP_chacha20(3), EVP_des_cbc(3), EVP_desx_cbc(3), EVP_idea_cbc(3),
EVP_rc2_cbc(3), EVP_rc4(3), EVP_rc5_32_12_16_cbc(3), EVP_seed_cbc(3), EVP_sm4_cbc(3),
HISTORY
Support for OCB mode was added in OpenSSL 1.1.0.
EVP_CIPHER_CTX was made opaque in OpenSSL 1.1.0. As a result, EVP_CIPHER_CTX_reset()
appeared and EVP_CIPHER_CTX_cleanup() disappeared. EVP_CIPHER_CTX_init() remains as an
alias for EVP_CIPHER_CTX_reset().
The EVP_CIPHER_CTX_cipher() function was deprecated in OpenSSL 3.0; use
EVP_CIPHER_CTX_get0_cipher() instead.
The EVP_EncryptInit_ex2(), EVP_DecryptInit_ex2(), EVP_CipherInit_ex2(),
EVP_CIPHER_fetch(), EVP_CIPHER_free(), EVP_CIPHER_up_ref(), EVP_CIPHER_CTX_get0_cipher(),
EVP_CIPHER_CTX_get1_cipher(), EVP_CIPHER_get_params(), EVP_CIPHER_CTX_set_params(),
EVP_CIPHER_CTX_get_params(), EVP_CIPHER_gettable_params(),
EVP_CIPHER_settable_ctx_params(), EVP_CIPHER_gettable_ctx_params(),
EVP_CIPHER_CTX_settable_params() and EVP_CIPHER_CTX_gettable_params() functions were added
in 3.0.
The EVP_CIPHER_nid(), EVP_CIPHER_name(), EVP_CIPHER_block_size(), EVP_CIPHER_key_length(),
EVP_CIPHER_iv_length(), EVP_CIPHER_flags(), EVP_CIPHER_mode(), EVP_CIPHER_type(),
EVP_CIPHER_CTX_nid(), EVP_CIPHER_CTX_block_size(), EVP_CIPHER_CTX_key_length(),
EVP_CIPHER_CTX_iv_length(), EVP_CIPHER_CTX_tag_length(), EVP_CIPHER_CTX_num(),
EVP_CIPHER_CTX_type(), and EVP_CIPHER_CTX_mode() functions were renamed to include "get"
or "get0" in their names in OpenSSL 3.0, respectively. The old names are kept as non-
deprecated alias macros.
The EVP_CIPHER_CTX_encrypting() function was renamed to EVP_CIPHER_CTX_is_encrypting() in
OpenSSL 3.0. The old name is kept as non-deprecated alias macro.
The EVP_CIPHER_CTX_flags() macro was deprecated in OpenSSL 1.1.0.
COPYRIGHT
Copyright 2000-2022 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (the "License"). You may not use this file except
in compliance with the License. You can obtain a copy in the file LICENSE in the source
distribution or at <https://www.openssl.org/source/license.html>.