RSA

Data Structures
struct	mbedtls_rsa_context
	The RSA context structure. More...

Macros
#define	MBEDTLS_ERR_RSA_BAD_INPUT_DATA   -0x4080
	Bad input parameters to function. More...
#define	MBEDTLS_ERR_RSA_INVALID_PADDING   -0x4100
	Input data contains invalid padding and is rejected. More...
#define	MBEDTLS_ERR_RSA_KEY_GEN_FAILED   -0x4180
	Something failed during generation of a key. More...
#define	MBEDTLS_ERR_RSA_KEY_CHECK_FAILED   -0x4200
	Key failed to pass the validity check of the library. More...
#define	MBEDTLS_ERR_RSA_PUBLIC_FAILED   -0x4280
	The public key operation failed. More...
#define	MBEDTLS_ERR_RSA_PRIVATE_FAILED   -0x4300
	The private key operation failed. More...
#define	MBEDTLS_ERR_RSA_VERIFY_FAILED   -0x4380
	The PKCS#1 verification failed. More...
#define	MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE   -0x4400
	The output buffer for decryption is not large enough. More...
#define	MBEDTLS_ERR_RSA_RNG_FAILED   -0x4480
	The random generator failed to generate non-zeros. More...
#define	MBEDTLS_ERR_RSA_UNSUPPORTED_OPERATION   -0x4500
	The implementation does not offer the requested operation, for example, because of security violations or lack of functionality. More...
#define	MBEDTLS_ERR_RSA_HW_ACCEL_FAILED   -0x4580
	RSA hardware accelerator failed. More...
#define	MBEDTLS_RSA_PUBLIC   0
	Request private key operation. More...
#define	MBEDTLS_RSA_PRIVATE   1
	Request public key operation. More...
#define	MBEDTLS_RSA_PKCS_V15   0
	Use PKCS#1 v1.5 encoding. More...
#define	MBEDTLS_RSA_PKCS_V21   1
	Use PKCS#1 v2.1 encoding. More...
#define	MBEDTLS_RSA_SIGN   1
	Identifier for RSA signature operations. More...
#define	MBEDTLS_RSA_CRYPT   2
	Identifier for RSA encryption and decryption operations. More...
#define	MBEDTLS_RSA_SALT_LEN_ANY   -1
	Constant for mbedtls_rsa_rsassa_pss_verify_ext to accept any salt length. More...

Typedefs
typedef struct mbedtls_rsa_context	mbedtls_rsa_context
	The RSA context structure. More...

Functions
void	mbedtls_rsa_init (mbedtls_rsa_context *ctx, int padding, int hash_id)
	This function initializes an RSA context. More...
int	mbedtls_rsa_import (mbedtls_rsa_context *ctx, const mbedtls_mpi *N, const mbedtls_mpi *P, const mbedtls_mpi *Q, const mbedtls_mpi *D, const mbedtls_mpi *E)
	This function imports a set of core parameters into an RSA context. More...
int	mbedtls_rsa_import_raw (mbedtls_rsa_context *ctx, unsigned char const *N, size_t N_len, unsigned char const *P, size_t P_len, unsigned char const *Q, size_t Q_len, unsigned char const *D, size_t D_len, unsigned char const *E, size_t E_len)
	This function imports core RSA parameters, in raw big-endian binary format, into an RSA context. More...
int	mbedtls_rsa_complete (mbedtls_rsa_context *ctx)
	This function completes an RSA context from a set of imported core parameters. More...
int	mbedtls_rsa_export (const mbedtls_rsa_context *ctx, mbedtls_mpi *N, mbedtls_mpi *P, mbedtls_mpi *Q, mbedtls_mpi *D, mbedtls_mpi *E)
	This function exports the core parameters of an RSA key. More...
int	mbedtls_rsa_export_raw (const mbedtls_rsa_context *ctx, unsigned char *N, size_t N_len, unsigned char *P, size_t P_len, unsigned char *Q, size_t Q_len, unsigned char *D, size_t D_len, unsigned char *E, size_t E_len)
	This function exports core parameters of an RSA key in raw big-endian binary format. More...
int	mbedtls_rsa_export_crt (const mbedtls_rsa_context *ctx, mbedtls_mpi *DP, mbedtls_mpi *DQ, mbedtls_mpi *QP)
	This function exports CRT parameters of a private RSA key. More...
void	mbedtls_rsa_set_padding (mbedtls_rsa_context *ctx, int padding, int hash_id)
	This function sets padding for an already initialized RSA context. More...
size_t	mbedtls_rsa_get_len (const mbedtls_rsa_context *ctx)
	This function retrieves the length of RSA modulus in Bytes. More...
int	mbedtls_rsa_gen_key (mbedtls_rsa_context *ctx, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng, unsigned int nbits, int exponent)
	This function generates an RSA keypair. More...
int	mbedtls_rsa_check_pubkey (const mbedtls_rsa_context *ctx)
	This function checks if a context contains at least an RSA public key. More...
int	mbedtls_rsa_check_privkey (const mbedtls_rsa_context *ctx)
	This function checks if a context contains an RSA private key and perform basic consistency checks. More...
int	mbedtls_rsa_check_pub_priv (const mbedtls_rsa_context *pub, const mbedtls_rsa_context *prv)
	This function checks a public-private RSA key pair. More...
int	mbedtls_rsa_public (mbedtls_rsa_context *ctx, const unsigned char *input, unsigned char *output)
	This function performs an RSA public key operation. More...
int	mbedtls_rsa_private (mbedtls_rsa_context *ctx, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng, const unsigned char *input, unsigned char *output)
	This function performs an RSA private key operation. More...
int	mbedtls_rsa_pkcs1_encrypt (mbedtls_rsa_context *ctx, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng, int mode, size_t ilen, const unsigned char *input, unsigned char *output)
	This function adds the message padding, then performs an RSA operation. More...
int	mbedtls_rsa_rsaes_pkcs1_v15_encrypt (mbedtls_rsa_context *ctx, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng, int mode, size_t ilen, const unsigned char *input, unsigned char *output)
	This function performs a PKCS#1 v1.5 encryption operation (RSAES-PKCS1-v1_5-ENCRYPT). More...
int	mbedtls_rsa_rsaes_oaep_encrypt (mbedtls_rsa_context *ctx, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng, int mode, const unsigned char *label, size_t label_len, size_t ilen, const unsigned char *input, unsigned char *output)
	This function performs a PKCS#1 v2.1 OAEP encryption operation (RSAES-OAEP-ENCRYPT). More...
int	mbedtls_rsa_pkcs1_decrypt (mbedtls_rsa_context *ctx, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng, int mode, size_t *olen, const unsigned char *input, unsigned char *output, size_t output_max_len)
	This function performs an RSA operation, then removes the message padding. More...
int	mbedtls_rsa_rsaes_pkcs1_v15_decrypt (mbedtls_rsa_context *ctx, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng, int mode, size_t *olen, const unsigned char *input, unsigned char *output, size_t output_max_len)
	This function performs a PKCS#1 v1.5 decryption operation (RSAES-PKCS1-v1_5-DECRYPT). More...
int	mbedtls_rsa_rsaes_oaep_decrypt (mbedtls_rsa_context *ctx, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng, int mode, const unsigned char *label, size_t label_len, size_t *olen, const unsigned char *input, unsigned char *output, size_t output_max_len)
	This function performs a PKCS#1 v2.1 OAEP decryption operation (RSAES-OAEP-DECRYPT). More...
int	mbedtls_rsa_pkcs1_sign (mbedtls_rsa_context *ctx, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng, int mode, mbedtls_md_type_t md_alg, unsigned int hashlen, const unsigned char *hash, unsigned char *sig)
	This function performs a private RSA operation to sign a message digest using PKCS#1. More...
int	mbedtls_rsa_rsassa_pkcs1_v15_sign (mbedtls_rsa_context *ctx, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng, int mode, mbedtls_md_type_t md_alg, unsigned int hashlen, const unsigned char *hash, unsigned char *sig)
	This function performs a PKCS#1 v1.5 signature operation (RSASSA-PKCS1-v1_5-SIGN). More...
int	mbedtls_rsa_rsassa_pss_sign (mbedtls_rsa_context *ctx, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng, int mode, mbedtls_md_type_t md_alg, unsigned int hashlen, const unsigned char *hash, unsigned char *sig)
	This function performs a PKCS#1 v2.1 PSS signature operation (RSASSA-PSS-SIGN). More...
int	mbedtls_rsa_pkcs1_verify (mbedtls_rsa_context *ctx, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng, int mode, mbedtls_md_type_t md_alg, unsigned int hashlen, const unsigned char *hash, const unsigned char *sig)
	This function performs a public RSA operation and checks the message digest. More...
int	mbedtls_rsa_rsassa_pkcs1_v15_verify (mbedtls_rsa_context *ctx, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng, int mode, mbedtls_md_type_t md_alg, unsigned int hashlen, const unsigned char *hash, const unsigned char *sig)
	This function performs a PKCS#1 v1.5 verification operation (RSASSA-PKCS1-v1_5-VERIFY). More...
int	mbedtls_rsa_rsassa_pss_verify (mbedtls_rsa_context *ctx, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng, int mode, mbedtls_md_type_t md_alg, unsigned int hashlen, const unsigned char *hash, const unsigned char *sig)
	This function performs a PKCS#1 v2.1 PSS verification operation (RSASSA-PSS-VERIFY). More...
int	mbedtls_rsa_rsassa_pss_verify_ext (mbedtls_rsa_context *ctx, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng, int mode, mbedtls_md_type_t md_alg, unsigned int hashlen, const unsigned char *hash, mbedtls_md_type_t mgf1_hash_id, int expected_salt_len, const unsigned char *sig)
	This function performs a PKCS#1 v2.1 PSS verification operation (RSASSA-PSS-VERIFY). More...
int	mbedtls_rsa_copy (mbedtls_rsa_context *dst, const mbedtls_rsa_context *src)
	This function copies the components of an RSA context. More...
void	mbedtls_rsa_free (mbedtls_rsa_context *ctx)
	This function frees the components of an RSA key. More...

Detailed Description

Macro Definition Documentation

MBEDTLS_ERR_RSA_BAD_INPUT_DATA

#define MBEDTLS_ERR_RSA_BAD_INPUT_DATA   -0x4080

Bad input parameters to function.

Definition at line 54 of file rsa.h.

MBEDTLS_ERR_RSA_INVALID_PADDING

#define MBEDTLS_ERR_RSA_INVALID_PADDING   -0x4100

Input data contains invalid padding and is rejected.

Definition at line 55 of file rsa.h.

MBEDTLS_ERR_RSA_KEY_GEN_FAILED

#define MBEDTLS_ERR_RSA_KEY_GEN_FAILED   -0x4180

Something failed during generation of a key.

Definition at line 56 of file rsa.h.

MBEDTLS_ERR_RSA_KEY_CHECK_FAILED

#define MBEDTLS_ERR_RSA_KEY_CHECK_FAILED   -0x4200

Key failed to pass the validity check of the library.

Definition at line 57 of file rsa.h.

MBEDTLS_ERR_RSA_PUBLIC_FAILED

#define MBEDTLS_ERR_RSA_PUBLIC_FAILED   -0x4280

The public key operation failed.

Definition at line 58 of file rsa.h.

MBEDTLS_ERR_RSA_PRIVATE_FAILED

#define MBEDTLS_ERR_RSA_PRIVATE_FAILED   -0x4300

The private key operation failed.

Definition at line 59 of file rsa.h.

MBEDTLS_ERR_RSA_VERIFY_FAILED

#define MBEDTLS_ERR_RSA_VERIFY_FAILED   -0x4380

The PKCS#1 verification failed.

Definition at line 60 of file rsa.h.

MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE

#define MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE   -0x4400

The output buffer for decryption is not large enough.

Definition at line 61 of file rsa.h.

MBEDTLS_ERR_RSA_RNG_FAILED

#define MBEDTLS_ERR_RSA_RNG_FAILED   -0x4480

The random generator failed to generate non-zeros.

Definition at line 62 of file rsa.h.

MBEDTLS_ERR_RSA_UNSUPPORTED_OPERATION

#define MBEDTLS_ERR_RSA_UNSUPPORTED_OPERATION   -0x4500

The implementation does not offer the requested operation, for example, because of security violations or lack of functionality.

Definition at line 66 of file rsa.h.

MBEDTLS_ERR_RSA_HW_ACCEL_FAILED

#define MBEDTLS_ERR_RSA_HW_ACCEL_FAILED   -0x4580

RSA hardware accelerator failed.

Definition at line 69 of file rsa.h.

MBEDTLS_RSA_PUBLIC

#define MBEDTLS_RSA_PUBLIC   0

Request private key operation.

Definition at line 74 of file rsa.h.

MBEDTLS_RSA_PRIVATE

#define MBEDTLS_RSA_PRIVATE   1

Request public key operation.

Definition at line 75 of file rsa.h.

MBEDTLS_RSA_PKCS_V15

#define MBEDTLS_RSA_PKCS_V15   0

Use PKCS#1 v1.5 encoding.

Definition at line 77 of file rsa.h.

MBEDTLS_RSA_PKCS_V21

#define MBEDTLS_RSA_PKCS_V21   1

Use PKCS#1 v2.1 encoding.

Definition at line 78 of file rsa.h.

MBEDTLS_RSA_SIGN

#define MBEDTLS_RSA_SIGN   1

Identifier for RSA signature operations.

Definition at line 80 of file rsa.h.

MBEDTLS_RSA_CRYPT

#define MBEDTLS_RSA_CRYPT   2

Identifier for RSA encryption and decryption operations.

Definition at line 81 of file rsa.h.

MBEDTLS_RSA_SALT_LEN_ANY

#define MBEDTLS_RSA_SALT_LEN_ANY   -1

Constant for mbedtls_rsa_rsassa_pss_verify_ext to accept any salt length.

Definition at line 83 of file rsa.h.

Typedef Documentation

mbedtls_rsa_context

typedef struct mbedtls_rsa_context mbedtls_rsa_context

The RSA context structure.

Note

Direct manipulation of the members of this structure is deprecated. All manipulation should instead be done through the public interface functions.

Function Documentation

mbedtls_rsa_init()

void mbedtls_rsa_init	(	mbedtls_rsa_context *	ctx,
		int	padding,
		int	hash_id
	)

This function initializes an RSA context.

Note

Set padding to MBEDTLS_RSA_PKCS_V21 for the RSAES-OAEP encryption scheme and the RSASSA-PSS signature scheme.

The hash_id parameter is ignored when using MBEDTLS_RSA_PKCS_V15 padding.

The choice of padding mode is strictly enforced for private key operations, since there might be security concerns in mixing padding modes. For public key operations it is a default value, which can be overridden by calling specific rsa_rsaes_xxx or rsa_rsassa_xxx functions.

The hash selected in hash_id is always used for OEAP encryption. For PSS signatures, it is always used for making signatures, but can be overridden for verifying them. If set to MBEDTLS_MD_NONE, it is always overridden.

Parameters

ctx	The RSA context to initialize. This must not be NULL.
padding	The padding mode to use. This must be either MBEDTLS_RSA_PKCS_V15 or MBEDTLS_RSA_PKCS_V21.
hash_id	The hash identifier of mbedtls_md_type_t type, if padding is MBEDTLS_RSA_PKCS_V21. It is unused otherwise.

mbedtls_rsa_import()

int mbedtls_rsa_import	(	mbedtls_rsa_context *	ctx,
		const mbedtls_mpi *	N,
		const mbedtls_mpi *	P,
		const mbedtls_mpi *	Q,
		const mbedtls_mpi *	D,
		const mbedtls_mpi *	E
	)

This function imports a set of core parameters into an RSA context.

Note

This function can be called multiple times for successive imports, if the parameters are not simultaneously present.

Any sequence of calls to this function should be followed by a call to mbedtls_rsa_complete(), which checks and completes the provided information to a ready-for-use public or private RSA key.

Note

See mbedtls_rsa_complete() for more information on which parameters are necessary to set up a private or public RSA key.

The imported parameters are copied and need not be preserved for the lifetime of the RSA context being set up.

Parameters

ctx	The initialized RSA context to store the parameters in.
N	The RSA modulus. This may be NULL.
P	The first prime factor of N. This may be NULL.
Q	The second prime factor of N. This may be NULL.
D	The private exponent. This may be NULL.
E	The public exponent. This may be NULL.

Returns

0 on success.

A non-zero error code on failure.

mbedtls_rsa_import_raw()

int mbedtls_rsa_import_raw	(	mbedtls_rsa_context *	ctx,
		unsigned char const *	N,
		size_t	N_len,
		unsigned char const *	P,
		size_t	P_len,
		unsigned char const *	Q,
		size_t	Q_len,
		unsigned char const *	D,
		size_t	D_len,
		unsigned char const *	E,
		size_t	E_len
	)

This function imports core RSA parameters, in raw big-endian binary format, into an RSA context.

Note

This function can be called multiple times for successive imports, if the parameters are not simultaneously present.

Any sequence of calls to this function should be followed by a call to mbedtls_rsa_complete(), which checks and completes the provided information to a ready-for-use public or private RSA key.

Note

See mbedtls_rsa_complete() for more information on which parameters are necessary to set up a private or public RSA key.

The imported parameters are copied and need not be preserved for the lifetime of the RSA context being set up.

Parameters

ctx	The initialized RSA context to store the parameters in.
N	The RSA modulus. This may be NULL.
N_len	The Byte length of N; it is ignored if N == NULL.
P	The first prime factor of N. This may be NULL.
P_len	The Byte length of P; it ns ignored if P == NULL.
Q	The second prime factor of N. This may be NULL.
Q_len	The Byte length of Q; it is ignored if Q == NULL.
D	The private exponent. This may be NULL.
D_len	The Byte length of D; it is ignored if D == NULL.
E	The public exponent. This may be NULL.
E_len	The Byte length of E; it is ignored if E == NULL.

Returns

0 on success.

A non-zero error code on failure.

mbedtls_rsa_complete()

int mbedtls_rsa_complete

(

mbedtls_rsa_context *

ctx

)

This function completes an RSA context from a set of imported core parameters.

To setup an RSA public key, precisely N and E must have been imported.

To setup an RSA private key, sufficient information must be present for the other parameters to be derivable.

The default implementation supports the following:

• Derive P, Q from N, D, E.
• Derive N, D from P, Q, E.

Alternative implementations need not support these.

If this function runs successfully, it guarantees that the RSA context can be used for RSA operations without the risk of failure or crash.

Warning

This function need not perform consistency checks for the imported parameters. In particular, parameters that are not needed by the implementation might be silently discarded and left unchecked. To check the consistency of the key material, see mbedtls_rsa_check_privkey().

Parameters

ctx	The initialized RSA context holding imported parameters.

Returns

0 on success.

MBEDTLS_ERR_RSA_BAD_INPUT_DATA if the attempted derivations failed.

mbedtls_rsa_export()

int mbedtls_rsa_export	(	const mbedtls_rsa_context *	ctx,
		mbedtls_mpi *	N,
		mbedtls_mpi *	P,
		mbedtls_mpi *	Q,
		mbedtls_mpi *	D,
		mbedtls_mpi *	E
	)

This function exports the core parameters of an RSA key.

            If this function runs successfully, the non-NULL buffers
            pointed to by \p N, \p P, \p Q, \p D, and \p E are fully
            written, with additional unused space filled leading by
            zero Bytes.

            Possible reasons for returning
            #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED:<ul>
            <li>An alternative RSA implementation is in use, which
            stores the key externally, and either cannot or should
            not export it into RAM.</li>
            <li>A SW or HW implementation might not support a certain
            deduction. For example, \p P, \p Q from \p N, \p D,
            and \p E if the former are not part of the
            implementation.</li></ul>

            If the function fails due to an unsupported operation,
            the RSA context stays intact and remains usable.

Parameters

ctx	The initialized RSA context.
N	The MPI to hold the RSA modulus. This may be NULL if this field need not be exported.
P	The MPI to hold the first prime factor of N. This may be NULL if this field need not be exported.
Q	The MPI to hold the second prime factor of N. This may be NULL if this field need not be exported.
D	The MPI to hold the private exponent. This may be NULL if this field need not be exported.
E	The MPI to hold the public exponent. This may be NULL if this field need not be exported.

Returns

0 on success.

MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED if exporting the requested parameters cannot be done due to missing functionality or because of security policies.

A non-zero return code on any other failure.

mbedtls_rsa_export_raw()

int mbedtls_rsa_export_raw	(	const mbedtls_rsa_context *	ctx,
		unsigned char *	N,
		size_t	N_len,
		unsigned char *	P,
		size_t	P_len,
		unsigned char *	Q,
		size_t	Q_len,
		unsigned char *	D,
		size_t	D_len,
		unsigned char *	E,
		size_t	E_len
	)

This function exports core parameters of an RSA key in raw big-endian binary format.

If this function runs successfully, the non-NULL buffers pointed to by N, P, Q, D, and E are fully written, with additional unused space filled leading by zero Bytes.

Possible reasons for returning MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED:

• An alternative RSA implementation is in use, which stores the key externally, and either cannot or should not export it into RAM.
• A SW or HW implementation might not support a certain deduction. For example, P, Q from N, D, and E if the former are not part of the implementation.

If the function fails due to an unsupported operation, the RSA context stays intact and remains usable.

Note

The length parameters are ignored if the corresponding buffer pointers are NULL.

Parameters

ctx	The initialized RSA context.
N	The Byte array to store the RSA modulus, or NULL if this field need not be exported.
N_len	The size of the buffer for the modulus.
P	The Byte array to hold the first prime factor of N, or NULL if this field need not be exported.
P_len	The size of the buffer for the first prime factor.
Q	The Byte array to hold the second prime factor of N, or NULL if this field need not be exported.
Q_len	The size of the buffer for the second prime factor.
D	The Byte array to hold the private exponent, or NULL if this field need not be exported.
D_len	The size of the buffer for the private exponent.
E	The Byte array to hold the public exponent, or NULL if this field need not be exported.
E_len	The size of the buffer for the public exponent.

Returns

0 on success.

MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED if exporting the requested parameters cannot be done due to missing functionality or because of security policies.

A non-zero return code on any other failure.

mbedtls_rsa_export_crt()

int mbedtls_rsa_export_crt	(	const mbedtls_rsa_context *	ctx,
		mbedtls_mpi *	DP,
		mbedtls_mpi *	DQ,
		mbedtls_mpi *	QP
	)

This function exports CRT parameters of a private RSA key.

Note

Alternative RSA implementations not using CRT-parameters internally can implement this function based on mbedtls_rsa_deduce_opt().

Parameters

ctx	The initialized RSA context.
DP	The MPI to hold D modulo P-1, or NULL if it need not be exported.
DQ	The MPI to hold D modulo Q-1, or NULL if it need not be exported.
QP	The MPI to hold modular inverse of Q modulo P, or NULL if it need not be exported.

Returns

0 on success.

A non-zero error code on failure.

mbedtls_rsa_set_padding()

void mbedtls_rsa_set_padding	(	mbedtls_rsa_context *	ctx,
		int	padding,
		int	hash_id
	)

This function sets padding for an already initialized RSA context.

See mbedtls_rsa_init() for details.

Parameters

ctx	The initialized RSA context to be configured.
padding	The padding mode to use. This must be either MBEDTLS_RSA_PKCS_V15 or MBEDTLS_RSA_PKCS_V21.
hash_id	The MBEDTLS_RSA_PKCS_V21 hash identifier.

mbedtls_rsa_get_len()

size_t mbedtls_rsa_get_len

(

const mbedtls_rsa_context *

ctx

)

This function retrieves the length of RSA modulus in Bytes.

Parameters

ctx	The initialized RSA context.

Returns

The length of the RSA modulus in Bytes.

mbedtls_rsa_gen_key()

int mbedtls_rsa_gen_key	(	mbedtls_rsa_context *	ctx,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng,
		unsigned int	nbits,
		int	exponent
	)

This function generates an RSA keypair.

Note

mbedtls_rsa_init() must be called before this function, to set up the RSA context.

Parameters

ctx	The initialized RSA context used to hold the key.
f_rng	The RNG function to be used for key generation. This must not be NULL.
p_rng	The RNG context to be passed to f_rng. This may be NULL if f_rng doesn't need a context.
nbits	The size of the public key in bits.
exponent	The public exponent to use. For example, 65537. This must be odd and greater than 1.

Returns

0 on success.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_check_pubkey()

int mbedtls_rsa_check_pubkey

(

const mbedtls_rsa_context *

ctx

)

This function checks if a context contains at least an RSA public key.

If the function runs successfully, it is guaranteed that enough information is present to perform an RSA public key operation using mbedtls_rsa_public().

Parameters

ctx	The initialized RSA context to check.

Returns

0 on success.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_check_privkey()

int mbedtls_rsa_check_privkey

(

const mbedtls_rsa_context *

ctx

)

This function checks if a context contains an RSA private key and perform basic consistency checks.

Note

The consistency checks performed by this function not only ensure that mbedtls_rsa_private() can be called successfully on the given context, but that the various parameters are mutually consistent with high probability, in the sense that mbedtls_rsa_public() and mbedtls_rsa_private() are inverses.

Warning

This function should catch accidental misconfigurations like swapping of parameters, but it cannot establish full trust in neither the quality nor the consistency of the key material that was used to setup the given RSA context:

• Consistency: Imported parameters that are irrelevant for the implementation might be silently dropped. If dropped, the current function does not have access to them, and therefore cannot check them. See mbedtls_rsa_complete(). If you want to check the consistency of the entire content of an PKCS1-encoded RSA private key, for example, you should use mbedtls_rsa_validate_params() before setting up the RSA context. Additionally, if the implementation performs empirical checks, these checks substantiate but do not guarantee consistency.
• Quality: This function is not expected to perform extended quality assessments like checking that the prime factors are safe. Additionally, it is the responsibility of the user to ensure the trustworthiness of the source of his RSA parameters, which goes beyond what is effectively checkable by the library.

Parameters

ctx	The initialized RSA context to check.

Returns

0 on success.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_check_pub_priv()

int mbedtls_rsa_check_pub_priv	(	const mbedtls_rsa_context *	pub,
		const mbedtls_rsa_context *	prv
	)

This function checks a public-private RSA key pair.

            It checks each of the contexts, and makes sure they match.

Parameters

pub	The initialized RSA context holding the public key.
prv	The initialized RSA context holding the private key.

Returns

0 on success.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_public()

int mbedtls_rsa_public	(	mbedtls_rsa_context *	ctx,
		const unsigned char *	input,
		unsigned char *	output
	)

This function performs an RSA public key operation.

Parameters

ctx	The initialized RSA context to use.
input	The input buffer. This must be a readable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus.
output	The output buffer. This must be a writable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus.

Note

This function does not handle message padding.

Make sure to set input[0] = 0 or ensure that input is smaller than N.

Returns

0 on success.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_private()

int mbedtls_rsa_private	(	mbedtls_rsa_context *	ctx,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng,
		const unsigned char *	input,
		unsigned char *	output
	)

This function performs an RSA private key operation.

Note

Blinding is used if and only if a PRNG is provided.

If blinding is used, both the base of exponentation and the exponent are blinded, providing protection against some side-channel attacks.

Warning

It is deprecated and a security risk to not provide a PRNG here and thereby prevent the use of blinding. Future versions of the library may enforce the presence of a PRNG.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function, used for blinding. It is discouraged and deprecated to pass NULL here, in which case blinding will be omitted.
p_rng	The RNG context to pass to f_rng. This may be NULL if f_rng is NULL or if f_rng doesn't need a context.
input	The input buffer. This must be a readable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus.
output	The output buffer. This must be a writable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus.

Returns

0 on success.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_pkcs1_encrypt()

int mbedtls_rsa_pkcs1_encrypt	(	mbedtls_rsa_context *	ctx,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng,
		int	mode,
		size_t	ilen,
		const unsigned char *	input,
		unsigned char *	output
	)

This function adds the message padding, then performs an RSA operation.

It is the generic wrapper for performing a PKCS#1 encryption operation using the mode from the context.

Deprecated:

It is deprecated and discouraged to call this function in MBEDTLS_RSA_PRIVATE mode. Future versions of the library are likely to remove the mode argument and have it implicitly set to MBEDTLS_RSA_PUBLIC.

Note

Alternative implementations of RSA need not support mode being set to MBEDTLS_RSA_PRIVATE and might instead return MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG to use. It is mandatory for PKCS#1 v2.1 padding encoding, and for PKCS#1 v1.5 padding encoding when used with mode set to MBEDTLS_RSA_PUBLIC. For PKCS#1 v1.5 padding encoding and mode set to MBEDTLS_RSA_PRIVATE, it is used for blinding and should be provided in this case; see mbedtls_rsa_private() for more.
p_rng	The RNG context to be passed to f_rng. May be NULL if f_rng is NULL or if f_rng doesn't need a context argument.
mode	The mode of operation. This must be either MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE (deprecated).
ilen	The length of the plaintext in Bytes.
input	The input data to encrypt. This must be a readable buffer of size ilen Bytes. It may be NULL if ilen == 0.
output	The output buffer. This must be a writable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus.

Returns

0 on success.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_rsaes_pkcs1_v15_encrypt()

int mbedtls_rsa_rsaes_pkcs1_v15_encrypt	(	mbedtls_rsa_context *	ctx,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng,
		int	mode,
		size_t	ilen,
		const unsigned char *	input,
		unsigned char *	output
	)

This function performs a PKCS#1 v1.5 encryption operation (RSAES-PKCS1-v1_5-ENCRYPT).

Deprecated:

It is deprecated and discouraged to call this function in MBEDTLS_RSA_PRIVATE mode. Future versions of the library are likely to remove the mode argument and have it implicitly set to MBEDTLS_RSA_PUBLIC.

Note

Alternative implementations of RSA need not support mode being set to MBEDTLS_RSA_PRIVATE and might instead return MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function to use. It is needed for padding generation if mode is MBEDTLS_RSA_PUBLIC. If mode is MBEDTLS_RSA_PRIVATE (discouraged), it is used for blinding and should be provided; see mbedtls_rsa_private().
p_rng	The RNG context to be passed to f_rng. This may be NULL if f_rng is NULL or if f_rng doesn't need a context argument.
mode	The mode of operation. This must be either MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE (deprecated).
ilen	The length of the plaintext in Bytes.
input	The input data to encrypt. This must be a readable buffer of size ilen Bytes. It may be NULL if ilen == 0.
output	The output buffer. This must be a writable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus.

Returns

0 on success.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_rsaes_oaep_encrypt()

int mbedtls_rsa_rsaes_oaep_encrypt	(	mbedtls_rsa_context *	ctx,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng,
		int	mode,
		const unsigned char *	label,
		size_t	label_len,
		size_t	ilen,
		const unsigned char *	input,
		unsigned char *	output
	)

This function performs a PKCS#1 v2.1 OAEP encryption operation (RSAES-OAEP-ENCRYPT).

Note

The output buffer must be as large as the size of ctx->N. For example, 128 Bytes if RSA-1024 is used.

Deprecated:

It is deprecated and discouraged to call this function in MBEDTLS_RSA_PRIVATE mode. Future versions of the library are likely to remove the mode argument and have it implicitly set to MBEDTLS_RSA_PUBLIC.

Note

Alternative implementations of RSA need not support mode being set to MBEDTLS_RSA_PRIVATE and might instead return MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.

Parameters

ctx	The initnialized RSA context to use.
f_rng	The RNG function to use. This is needed for padding generation and must be provided.
p_rng	The RNG context to be passed to f_rng. This may be NULL if f_rng doesn't need a context argument.
mode	The mode of operation. This must be either MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE (deprecated).
label	The buffer holding the custom label to use. This must be a readable buffer of length label_len Bytes. It may be NULL if label_len is 0.
label_len	The length of the label in Bytes.
ilen	The length of the plaintext buffer input in Bytes.
input	The input data to encrypt. This must be a readable buffer of size ilen Bytes. It may be NULL if ilen == 0.
output	The output buffer. This must be a writable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus.

Returns

0 on success.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_pkcs1_decrypt()

int mbedtls_rsa_pkcs1_decrypt	(	mbedtls_rsa_context *	ctx,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng,
		int	mode,
		size_t *	olen,
		const unsigned char *	input,
		unsigned char *	output,
		size_t	output_max_len
	)

This function performs an RSA operation, then removes the message padding.

It is the generic wrapper for performing a PKCS#1 decryption operation using the mode from the context.

Note

The output buffer length output_max_len should be as large as the size ctx->len of ctx->N (for example, 128 Bytes if RSA-1024 is used) to be able to hold an arbitrary decrypted message. If it is not large enough to hold the decryption of the particular ciphertext provided, the function returns MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE.

Deprecated:

It is deprecated and discouraged to call this function in MBEDTLS_RSA_PUBLIC mode. Future versions of the library are likely to remove the mode argument and have it implicitly set to MBEDTLS_RSA_PRIVATE.

Note

Alternative implementations of RSA need not support mode being set to MBEDTLS_RSA_PUBLIC and might instead return MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function. If mode is MBEDTLS_RSA_PRIVATE, this is used for blinding and should be provided; see mbedtls_rsa_private() for more. If mode is MBEDTLS_RSA_PUBLIC, it is ignored.
p_rng	The RNG context to be passed to f_rng. This may be NULL if f_rng is NULL or doesn't need a context.
mode	The mode of operation. This must be either MBEDTLS_RSA_PRIVATE or MBEDTLS_RSA_PUBLIC (deprecated).
olen	The address at which to store the length of the plaintext. This must not be NULL.
input	The ciphertext buffer. This must be a readable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus.
output	The buffer used to hold the plaintext. This must be a writable buffer of length output_max_len Bytes.
output_max_len	The length in Bytes of the output buffer output.

Returns

0 on success.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_rsaes_pkcs1_v15_decrypt()

int mbedtls_rsa_rsaes_pkcs1_v15_decrypt	(	mbedtls_rsa_context *	ctx,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng,
		int	mode,
		size_t *	olen,
		const unsigned char *	input,
		unsigned char *	output,
		size_t	output_max_len
	)

This function performs a PKCS#1 v1.5 decryption operation (RSAES-PKCS1-v1_5-DECRYPT).

Note

The output buffer length output_max_len should be as large as the size ctx->len of ctx->N, for example, 128 Bytes if RSA-1024 is used, to be able to hold an arbitrary decrypted message. If it is not large enough to hold the decryption of the particular ciphertext provided, the function returns MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE.

Deprecated:

It is deprecated and discouraged to call this function in MBEDTLS_RSA_PUBLIC mode. Future versions of the library are likely to remove the mode argument and have it implicitly set to MBEDTLS_RSA_PRIVATE.

Note

Alternative implementations of RSA need not support mode being set to MBEDTLS_RSA_PUBLIC and might instead return MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function. If mode is MBEDTLS_RSA_PRIVATE, this is used for blinding and should be provided; see mbedtls_rsa_private() for more. If mode is MBEDTLS_RSA_PUBLIC, it is ignored.
p_rng	The RNG context to be passed to f_rng. This may be NULL if f_rng is NULL or doesn't need a context.
mode	The mode of operation. This must be either MBEDTLS_RSA_PRIVATE or MBEDTLS_RSA_PUBLIC (deprecated).
olen	The address at which to store the length of the plaintext. This must not be NULL.
input	The ciphertext buffer. This must be a readable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus.
output	The buffer used to hold the plaintext. This must be a writable buffer of length output_max_len Bytes.
output_max_len	The length in Bytes of the output buffer output.

Returns

0 on success.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_rsaes_oaep_decrypt()

int mbedtls_rsa_rsaes_oaep_decrypt	(	mbedtls_rsa_context *	ctx,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng,
		int	mode,
		const unsigned char *	label,
		size_t	label_len,
		size_t *	olen,
		const unsigned char *	input,
		unsigned char *	output,
		size_t	output_max_len
	)

This function performs a PKCS#1 v2.1 OAEP decryption operation (RSAES-OAEP-DECRYPT).

Note

The output buffer length output_max_len should be as large as the size ctx->len of ctx->N, for example, 128 Bytes if RSA-1024 is used, to be able to hold an arbitrary decrypted message. If it is not large enough to hold the decryption of the particular ciphertext provided, the function returns MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE.

Deprecated:

It is deprecated and discouraged to call this function in MBEDTLS_RSA_PUBLIC mode. Future versions of the library are likely to remove the mode argument and have it implicitly set to MBEDTLS_RSA_PRIVATE.

Note

Alternative implementations of RSA need not support mode being set to MBEDTLS_RSA_PUBLIC and might instead return MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function. If mode is MBEDTLS_RSA_PRIVATE, this is used for blinding and should be provided; see mbedtls_rsa_private() for more. If mode is MBEDTLS_RSA_PUBLIC, it is ignored.
p_rng	The RNG context to be passed to f_rng. This may be NULL if f_rng is NULL or doesn't need a context.
mode	The mode of operation. This must be either MBEDTLS_RSA_PRIVATE or MBEDTLS_RSA_PUBLIC (deprecated).
label	The buffer holding the custom label to use. This must be a readable buffer of length label_len Bytes. It may be NULL if label_len is 0.
label_len	The length of the label in Bytes.
olen	The address at which to store the length of the plaintext. This must not be NULL.
input	The ciphertext buffer. This must be a readable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus.
output	The buffer used to hold the plaintext. This must be a writable buffer of length output_max_len Bytes.
output_max_len	The length in Bytes of the output buffer output.

Returns

0 on success.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_pkcs1_sign()

int mbedtls_rsa_pkcs1_sign	(	mbedtls_rsa_context *	ctx,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng,
		int	mode,
		mbedtls_md_type_t	md_alg,
		unsigned int	hashlen,
		const unsigned char *	hash,
		unsigned char *	sig
	)

This function performs a private RSA operation to sign a message digest using PKCS#1.

It is the generic wrapper for performing a PKCS#1 signature using the mode from the context.

Note

The sig buffer must be as large as the size of ctx->N. For example, 128 Bytes if RSA-1024 is used.

For PKCS#1 v2.1 encoding, see comments on mbedtls_rsa_rsassa_pss_sign() for details on md_alg and hash_id.

Deprecated:

It is deprecated and discouraged to call this function in MBEDTLS_RSA_PUBLIC mode. Future versions of the library are likely to remove the mode argument and have it implicitly set to MBEDTLS_RSA_PRIVATE.

Note

Alternative implementations of RSA need not support mode being set to MBEDTLS_RSA_PUBLIC and might instead return MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function to use. If the padding mode is PKCS#1 v2.1, this must be provided. If the padding mode is PKCS#1 v1.5 and mode is MBEDTLS_RSA_PRIVATE, it is used for blinding and should be provided; see mbedtls_rsa_private() for more more. It is ignored otherwise.
p_rng	The RNG context to be passed to f_rng. This may be NULL if f_rng is NULL or doesn't need a context argument.
mode	The mode of operation. This must be either MBEDTLS_RSA_PRIVATE or MBEDTLS_RSA_PUBLIC (deprecated).
md_alg	The message-digest algorithm used to hash the original data. Use MBEDTLS_MD_NONE for signing raw data.
hashlen	The length of the message digest. Ths is only used if md_alg is MBEDTLS_MD_NONE.
hash	The buffer holding the message digest or raw data. If md_alg is MBEDTLS_MD_NONE, this must be a readable buffer of length hashlen Bytes. If md_alg is not MBEDTLS_MD_NONE, it must be a readable buffer of length the size of the hash corresponding to md_alg.
sig	The buffer to hold the signature. This must be a writable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus. A buffer length of MBEDTLS_MPI_MAX_SIZE is always safe.

Returns

0 if the signing operation was successful.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_rsassa_pkcs1_v15_sign()

int mbedtls_rsa_rsassa_pkcs1_v15_sign	(	mbedtls_rsa_context *	ctx,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng,
		int	mode,
		mbedtls_md_type_t	md_alg,
		unsigned int	hashlen,
		const unsigned char *	hash,
		unsigned char *	sig
	)

This function performs a PKCS#1 v1.5 signature operation (RSASSA-PKCS1-v1_5-SIGN).

Deprecated:

It is deprecated and discouraged to call this function in MBEDTLS_RSA_PUBLIC mode. Future versions of the library are likely to remove the mode argument and have it implicitly set to MBEDTLS_RSA_PRIVATE.

Note

Alternative implementations of RSA need not support mode being set to MBEDTLS_RSA_PUBLIC and might instead return MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function. If mode is MBEDTLS_RSA_PRIVATE, this is used for blinding and should be provided; see mbedtls_rsa_private() for more. If mode is MBEDTLS_RSA_PUBLIC, it is ignored.
p_rng	The RNG context to be passed to f_rng. This may be NULL if f_rng is NULL or doesn't need a context argument.
mode	The mode of operation. This must be either MBEDTLS_RSA_PRIVATE or MBEDTLS_RSA_PUBLIC (deprecated).
md_alg	The message-digest algorithm used to hash the original data. Use MBEDTLS_MD_NONE for signing raw data.
hashlen	The length of the message digest. Ths is only used if md_alg is MBEDTLS_MD_NONE.
hash	The buffer holding the message digest or raw data. If md_alg is MBEDTLS_MD_NONE, this must be a readable buffer of length hashlen Bytes. If md_alg is not MBEDTLS_MD_NONE, it must be a readable buffer of length the size of the hash corresponding to md_alg.
sig	The buffer to hold the signature. This must be a writable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus. A buffer length of MBEDTLS_MPI_MAX_SIZE is always safe.

Returns

0 if the signing operation was successful.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_rsassa_pss_sign()

int mbedtls_rsa_rsassa_pss_sign	(	mbedtls_rsa_context *	ctx,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng,
		int	mode,
		mbedtls_md_type_t	md_alg,
		unsigned int	hashlen,
		const unsigned char *	hash,
		unsigned char *	sig
	)

This function performs a PKCS#1 v2.1 PSS signature operation (RSASSA-PSS-SIGN).

Note

The hash_id in the RSA context is the one used for the encoding. md_alg in the function call is the type of hash that is encoded. According to RFC-3447: Public-Key Cryptography Standards (PKCS) #1 v2.1: RSA Cryptography Specifications it is advised to keep both hashes the same.

This function always uses the maximum possible salt size, up to the length of the payload hash. This choice of salt size complies with FIPS 186-4 §5.5 (e) and RFC 8017 (PKCS#1 v2.2) §9.1.1 step 3. Furthermore this function enforces a minimum salt size which is the hash size minus 2 bytes. If this minimum size is too large given the key size (the salt size, plus the hash size, plus 2 bytes must be no more than the key size in bytes), this function returns MBEDTLS_ERR_RSA_BAD_INPUT_DATA.

Deprecated:

It is deprecated and discouraged to call this function in MBEDTLS_RSA_PUBLIC mode. Future versions of the library are likely to remove the mode argument and have it implicitly set to MBEDTLS_RSA_PRIVATE.

Note

Alternative implementations of RSA need not support mode being set to MBEDTLS_RSA_PUBLIC and might instead return MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function. It must not be NULL.
p_rng	The RNG context to be passed to f_rng. This may be NULL if f_rng doesn't need a context argument.
mode	The mode of operation. This must be either MBEDTLS_RSA_PRIVATE or MBEDTLS_RSA_PUBLIC (deprecated).
md_alg	The message-digest algorithm used to hash the original data. Use MBEDTLS_MD_NONE for signing raw data.
hashlen	The length of the message digest. Ths is only used if md_alg is MBEDTLS_MD_NONE.
hash	The buffer holding the message digest or raw data. If md_alg is MBEDTLS_MD_NONE, this must be a readable buffer of length hashlen Bytes. If md_alg is not MBEDTLS_MD_NONE, it must be a readable buffer of length the size of the hash corresponding to md_alg.
sig	The buffer to hold the signature. This must be a writable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus. A buffer length of MBEDTLS_MPI_MAX_SIZE is always safe.

Returns

0 if the signing operation was successful.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_pkcs1_verify()

int mbedtls_rsa_pkcs1_verify	(	mbedtls_rsa_context *	ctx,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng,
		int	mode,
		mbedtls_md_type_t	md_alg,
		unsigned int	hashlen,
		const unsigned char *	hash,
		const unsigned char *	sig
	)

This function performs a public RSA operation and checks the message digest.

This is the generic wrapper for performing a PKCS#1 verification using the mode from the context.

Note

For PKCS#1 v2.1 encoding, see comments on mbedtls_rsa_rsassa_pss_verify() about md_alg and hash_id.

Deprecated:

It is deprecated and discouraged to call this function in MBEDTLS_RSA_PRIVATE mode. Future versions of the library are likely to remove the mode argument and have it set to MBEDTLS_RSA_PUBLIC.

Note

Alternative implementations of RSA need not support mode being set to MBEDTLS_RSA_PRIVATE and might instead return MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.

Parameters

ctx	The initialized RSA public key context to use.
f_rng	The RNG function to use. If mode is MBEDTLS_RSA_PRIVATE, this is used for blinding and should be provided; see mbedtls_rsa_private() for more. Otherwise, it is ignored.
p_rng	The RNG context to be passed to f_rng. This may be NULL if f_rng is NULL or doesn't need a context.
mode	The mode of operation. This must be either MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE (deprecated).
md_alg	The message-digest algorithm used to hash the original data. Use MBEDTLS_MD_NONE for signing raw data.
hashlen	The length of the message digest. This is only used if md_alg is MBEDTLS_MD_NONE.
hash	The buffer holding the message digest or raw data. If md_alg is MBEDTLS_MD_NONE, this must be a readable buffer of length hashlen Bytes. If md_alg is not MBEDTLS_MD_NONE, it must be a readable buffer of length the size of the hash corresponding to md_alg.
sig	The buffer holding the signature. This must be a readable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus.

Returns

0 if the verify operation was successful.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_rsassa_pkcs1_v15_verify()

int mbedtls_rsa_rsassa_pkcs1_v15_verify	(	mbedtls_rsa_context *	ctx,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng,
		int	mode,
		mbedtls_md_type_t	md_alg,
		unsigned int	hashlen,
		const unsigned char *	hash,
		const unsigned char *	sig
	)

This function performs a PKCS#1 v1.5 verification operation (RSASSA-PKCS1-v1_5-VERIFY).

Deprecated:

It is deprecated and discouraged to call this function in MBEDTLS_RSA_PRIVATE mode. Future versions of the library are likely to remove the mode argument and have it set to MBEDTLS_RSA_PUBLIC.

Note

Alternative implementations of RSA need not support mode being set to MBEDTLS_RSA_PRIVATE and might instead return MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.

Parameters

ctx	The initialized RSA public key context to use.
f_rng	The RNG function to use. If mode is MBEDTLS_RSA_PRIVATE, this is used for blinding and should be provided; see mbedtls_rsa_private() for more. Otherwise, it is ignored.
p_rng	The RNG context to be passed to f_rng. This may be NULL if f_rng is NULL or doesn't need a context.
mode	The mode of operation. This must be either MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE (deprecated).
md_alg	The message-digest algorithm used to hash the original data. Use MBEDTLS_MD_NONE for signing raw data.
hashlen	The length of the message digest. This is only used if md_alg is MBEDTLS_MD_NONE.
hash	The buffer holding the message digest or raw data. If md_alg is MBEDTLS_MD_NONE, this must be a readable buffer of length hashlen Bytes. If md_alg is not MBEDTLS_MD_NONE, it must be a readable buffer of length the size of the hash corresponding to md_alg.
sig	The buffer holding the signature. This must be a readable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus.

Returns

0 if the verify operation was successful.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_rsassa_pss_verify()

int mbedtls_rsa_rsassa_pss_verify	(	mbedtls_rsa_context *	ctx,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng,
		int	mode,
		mbedtls_md_type_t	md_alg,
		unsigned int	hashlen,
		const unsigned char *	hash,
		const unsigned char *	sig
	)

This function performs a PKCS#1 v2.1 PSS verification operation (RSASSA-PSS-VERIFY).

The hash function for the MGF mask generating function is that specified in the RSA context.

Note

The hash_id in the RSA context is the one used for the verification. md_alg in the function call is the type of hash that is verified. According to RFC-3447: Public-Key Cryptography Standards (PKCS) #1 v2.1: RSA Cryptography Specifications it is advised to keep both hashes the same. If hash_id in the RSA context is unset, the md_alg from the function call is used.

Deprecated:

It is deprecated and discouraged to call this function in MBEDTLS_RSA_PRIVATE mode. Future versions of the library are likely to remove the mode argument and have it implicitly set to MBEDTLS_RSA_PUBLIC.

Note

Alternative implementations of RSA need not support mode being set to MBEDTLS_RSA_PRIVATE and might instead return MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.

Parameters

ctx	The initialized RSA public key context to use.
f_rng	The RNG function to use. If mode is MBEDTLS_RSA_PRIVATE, this is used for blinding and should be provided; see mbedtls_rsa_private() for more. Otherwise, it is ignored.
p_rng	The RNG context to be passed to f_rng. This may be NULL if f_rng is NULL or doesn't need a context.
mode	The mode of operation. This must be either MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE (deprecated).
md_alg	The message-digest algorithm used to hash the original data. Use MBEDTLS_MD_NONE for signing raw data.
hashlen	The length of the message digest. This is only used if md_alg is MBEDTLS_MD_NONE.
hash	The buffer holding the message digest or raw data. If md_alg is MBEDTLS_MD_NONE, this must be a readable buffer of length hashlen Bytes. If md_alg is not MBEDTLS_MD_NONE, it must be a readable buffer of length the size of the hash corresponding to md_alg.
sig	The buffer holding the signature. This must be a readable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus.

Returns

0 if the verify operation was successful.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_rsassa_pss_verify_ext()

int mbedtls_rsa_rsassa_pss_verify_ext	(	mbedtls_rsa_context *	ctx,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng,
		int	mode,
		mbedtls_md_type_t	md_alg,
		unsigned int	hashlen,
		const unsigned char *	hash,
		mbedtls_md_type_t	mgf1_hash_id,
		int	expected_salt_len,
		const unsigned char *	sig
	)

This function performs a PKCS#1 v2.1 PSS verification operation (RSASSA-PSS-VERIFY).

The hash function for the MGF mask generating function is that specified in mgf1_hash_id.

Note

The sig buffer must be as large as the size of ctx->N. For example, 128 Bytes if RSA-1024 is used.

The hash_id in the RSA context is ignored.

Parameters

ctx	The initialized RSA public key context to use.
f_rng	The RNG function to use. If mode is MBEDTLS_RSA_PRIVATE, this is used for blinding and should be provided; see mbedtls_rsa_private() for more. Otherwise, it is ignored.
p_rng	The RNG context to be passed to f_rng. This may be NULL if f_rng is NULL or doesn't need a context.
mode	The mode of operation. This must be either MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE.
md_alg	The message-digest algorithm used to hash the original data. Use MBEDTLS_MD_NONE for signing raw data.
hashlen	The length of the message digest. This is only used if md_alg is MBEDTLS_MD_NONE.
hash	The buffer holding the message digest or raw data. If md_alg is MBEDTLS_MD_NONE, this must be a readable buffer of length hashlen Bytes. If md_alg is not MBEDTLS_MD_NONE, it must be a readable buffer of length the size of the hash corresponding to md_alg.
mgf1_hash_id	The message digest used for mask generation.
expected_salt_len	The length of the salt used in padding. Use MBEDTLS_RSA_SALT_LEN_ANY to accept any salt length.
sig	The buffer holding the signature. This must be a readable buffer of length ctx->len Bytes. For example, 256 Bytes for an 2048-bit RSA modulus.

Returns

0 if the verify operation was successful.

An MBEDTLS_ERR_RSA_XXX error code on failure.

mbedtls_rsa_copy()

int mbedtls_rsa_copy	(	mbedtls_rsa_context *	dst,
		const mbedtls_rsa_context *	src
	)

This function copies the components of an RSA context.

Parameters

dst	The destination context. This must be initialized.
src	The source context. This must be initialized.

Returns

0 on success.

MBEDTLS_ERR_MPI_ALLOC_FAILED on memory allocation failure.

mbedtls_rsa_free()

void mbedtls_rsa_free

(

mbedtls_rsa_context *

ctx

)

This function frees the components of an RSA key.

Parameters

ctx	The RSA context to free. May be NULL, in which case this function is a no-op. If it is not NULL, it must point to an initialized RSA context.