This file provides an API for the RSA public-key cryptosystem. More...

#include "mbedtls/private_access.h"
#include "mbedtls/build_info.h"
#include "mbedtls/bignum.h"
#include "mbedtls/md.h"
#include "mbedtls/threading.h"
#include "rsa_alt.h"

Include dependency graph for rsa.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Macros
#define	MBEDTLS_ERR_RSA_BAD_INPUT_DATA -0x4080

#define	MBEDTLS_ERR_RSA_INVALID_PADDING -0x4100

#define	MBEDTLS_ERR_RSA_KEY_GEN_FAILED -0x4180

#define	MBEDTLS_ERR_RSA_KEY_CHECK_FAILED -0x4200

#define	MBEDTLS_ERR_RSA_PUBLIC_FAILED -0x4280

#define	MBEDTLS_ERR_RSA_PRIVATE_FAILED -0x4300

#define	MBEDTLS_ERR_RSA_VERIFY_FAILED -0x4380

#define	MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE -0x4400

#define	MBEDTLS_ERR_RSA_RNG_FAILED -0x4480

#define	MBEDTLS_RSA_PKCS_V15 0

#define	MBEDTLS_RSA_PKCS_V21 1

#define	MBEDTLS_RSA_SIGN 1

#define	MBEDTLS_RSA_CRYPT 2

#define	MBEDTLS_RSA_SALT_LEN_ANY -1

Functions
void	mbedtls_rsa_init (mbedtls_rsa_context *ctx)
	This function initializes an RSA context. More...

int	mbedtls_rsa_set_padding (mbedtls_rsa_context *ctx, int padding, mbedtls_md_type_t hash_id)
	This function sets padding for an already initialized 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...

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, 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, 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, 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, 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, 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, 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, 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, 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_ext (mbedtls_rsa_context ctx, int(f_rng)(void , unsigned char , size_t), void p_rng, mbedtls_md_type_t md_alg, unsigned int hashlen, const unsigned char hash, int saltlen, unsigned char *sig)
	This function performs a PKCS#1 v2.1 PSS signature operation (RSASSA-PSS-SIGN). More...

int	mbedtls_rsa_rsassa_pss_sign (mbedtls_rsa_context ctx, int(f_rng)(void , unsigned char , size_t), void p_rng, 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, 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, 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, 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, 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...

int	mbedtls_rsa_self_test (int verbose)
	The RSA checkup routine. More...

Detailed Description

This file provides an API for the RSA public-key cryptosystem.

The RSA public-key cryptosystem is defined in Public-Key Cryptography Standards (PKCS) #1 v1.5: RSA Encryption and Public-Key Cryptography Standards (PKCS) #1 v2.1: RSA Cryptography Specifications.

Definition in file rsa.h.

Macro Definition Documentation

#define MBEDTLS_ERR_RSA_BAD_INPUT_DATA -0x4080

Bad input parameters to function.

Definition at line 45 of file rsa.h.

#define MBEDTLS_ERR_RSA_INVALID_PADDING -0x4100

Input data contains invalid padding and is rejected.

Definition at line 47 of file rsa.h.

#define MBEDTLS_ERR_RSA_KEY_CHECK_FAILED -0x4200

Key failed to pass the validity check of the library.

Definition at line 51 of file rsa.h.

#define MBEDTLS_ERR_RSA_KEY_GEN_FAILED -0x4180

Something failed during generation of a key.

Definition at line 49 of file rsa.h.

#define MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE -0x4400

The output buffer for decryption is not large enough.

Definition at line 59 of file rsa.h.

#define MBEDTLS_ERR_RSA_PRIVATE_FAILED -0x4300

The private key operation failed.

Definition at line 55 of file rsa.h.

#define MBEDTLS_ERR_RSA_PUBLIC_FAILED -0x4280

The public key operation failed.

Definition at line 53 of file rsa.h.

#define MBEDTLS_ERR_RSA_RNG_FAILED -0x4480

The random generator failed to generate non-zeros.

Definition at line 61 of file rsa.h.

#define MBEDTLS_ERR_RSA_VERIFY_FAILED -0x4380

The PKCS#1 verification failed.

Definition at line 57 of file rsa.h.

#define MBEDTLS_RSA_CRYPT 2

Identifier for RSA encryption and decryption operations.

Definition at line 71 of file rsa.h.

#define MBEDTLS_RSA_PKCS_V15 0

Use PKCS#1 v1.5 encoding.

Definition at line 67 of file rsa.h.

#define MBEDTLS_RSA_PKCS_V21 1

Use PKCS#1 v2.1 encoding.

Definition at line 68 of file rsa.h.

#define MBEDTLS_RSA_SALT_LEN_ANY -1

Definition at line 73 of file rsa.h.

#define MBEDTLS_RSA_SIGN 1

Identifier for RSA signature operations.

Definition at line 70 of file rsa.h.

Function Documentation

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.

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.

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.

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.

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.

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 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.

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.

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.

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.

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.

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 is mandatory and 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.

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.

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.

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.

void mbedtls_rsa_init ( mbedtls_rsa_context * ctx )

This function initializes an RSA context.

Note: This function initializes the padding and the hash identifier to respectively MBEDTLS_RSA_PKCS_V15 and MBEDTLS_MD_NONE. See mbedtls_rsa_set_padding() for more information about those parameters.

Parameters

ctx	The RSA context to initialize. This must not be `NULL`.

int mbedtls_rsa_pkcs1_decrypt	(	mbedtls_rsa_context *	ctx,
		int()(void , unsigned char *, size_t)	f_rng,
		void *	p_rng,
		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.

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.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function. This is used for blinding and is mandatory; see mbedtls_rsa_private() for more.
p_rng	The RNG context to be passed to `f_rng`. This may be `NULL` if `f_rng` doesn't need a context.
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.

int mbedtls_rsa_pkcs1_encrypt	(	mbedtls_rsa_context *	ctx,
		int()(void , unsigned char *, size_t)	f_rng,
		void *	p_rng,
		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.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG to use. It is used for padding generation and it is mandatory.
p_rng	The RNG context to be passed to `f_rng`. May be `NULL` if `f_rng` doesn't need a context argument.
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.

int mbedtls_rsa_pkcs1_sign	(	mbedtls_rsa_context *	ctx,
		int()(void , unsigned char *, size_t)	f_rng,
		void *	p_rng,
		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.

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.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function to use. This is mandatory and 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.
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 or raw data in Bytes. If `md_alg` is not MBEDTLS_MD_NONE, this must match the output length of the corresponding hash algorithm.
hash	The buffer holding the message digest or raw data. This must be a readable buffer of at least `hashlen` Bytes.
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.

int mbedtls_rsa_pkcs1_verify	(	mbedtls_rsa_context *	ctx,
		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.

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

Parameters

ctx	The initialized RSA public key context to use.
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 or raw data in Bytes. If `md_alg` is not MBEDTLS_MD_NONE, this must match the output length of the corresponding hash algorithm.
hash	The buffer holding the message digest or raw data. This must be a readable buffer of at least `hashlen` Bytes.
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.

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 mandatory.
p_rng	The RNG context to pass to `f_rng`. This may be `NULL` 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.

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.

int mbedtls_rsa_rsaes_oaep_decrypt	(	mbedtls_rsa_context *	ctx,
		int()(void , unsigned char *, size_t)	f_rng,
		void *	p_rng,
		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.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function. This is used for blinding and is mandatory.
p_rng	The RNG context to be passed to `f_rng`. This may be `NULL` if `f_rng` doesn't need a context.
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.

int mbedtls_rsa_rsaes_oaep_encrypt	(	mbedtls_rsa_context *	ctx,
		int()(void , unsigned char *, size_t)	f_rng,
		void *	p_rng,
		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.

Parameters

ctx	The initnialized RSA context to use.
f_rng	The RNG function to use. This is needed for padding generation and is mandatory.
p_rng	The RNG context to be passed to `f_rng`. This may be `NULL` if `f_rng` doesn't need a context argument.
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.

int mbedtls_rsa_rsaes_pkcs1_v15_decrypt	(	mbedtls_rsa_context *	ctx,
		int()(void , unsigned char *, size_t)	f_rng,
		void *	p_rng,
		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.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function. This is used for blinding and is mandatory; see mbedtls_rsa_private() for more.
p_rng	The RNG context to be passed to `f_rng`. This may be `NULL` if `f_rng` doesn't need a context.
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.

int mbedtls_rsa_rsaes_pkcs1_v15_encrypt	(	mbedtls_rsa_context *	ctx,
		int()(void , unsigned char *, size_t)	f_rng,
		void *	p_rng,
		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).

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function to use. It is mandatory and used for padding generation.
p_rng	The RNG context to be passed to `f_rng`. This may be `NULL` if `f_rng` doesn't need a context argument.
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.

int mbedtls_rsa_rsassa_pkcs1_v15_sign	(	mbedtls_rsa_context *	ctx,
		int()(void , unsigned char *, size_t)	f_rng,
		void *	p_rng,
		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).

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function. This is used for blinding and is mandatory; see mbedtls_rsa_private() for more.
p_rng	The RNG context to be passed to `f_rng`. This may be `NULL` if `f_rng` doesn't need a context argument.
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 or raw data in Bytes. If `md_alg` is not MBEDTLS_MD_NONE, this must match the output length of the corresponding hash algorithm.
hash	The buffer holding the message digest or raw data. This must be a readable buffer of at least `hashlen` Bytes.
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.

int mbedtls_rsa_rsassa_pkcs1_v15_verify	(	mbedtls_rsa_context *	ctx,
		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).

Parameters

ctx	The initialized RSA public key context to use.
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 or raw data in Bytes. If `md_alg` is not MBEDTLS_MD_NONE, this must match the output length of the corresponding hash algorithm.
hash	The buffer holding the message digest or raw data. This must be a readable buffer of at least `hashlen` Bytes.
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.

int mbedtls_rsa_rsassa_pss_sign	(	mbedtls_rsa_context *	ctx,
		int()(void , unsigned char *, size_t)	f_rng,
		void *	p_rng,
		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 set in ctx by calling mbedtls_rsa_set_padding() selects the hash used for the encoding operation and for the mask generation function (MGF1). For more details on the encoding operation and the mask generation function, consult RFC-3447: Public-Key Cryptography Standards (PKCS) #1 v2.1: RSA Cryptography Specifications.; 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.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function. It is mandatory and 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.
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 or raw data in Bytes. If `md_alg` is not MBEDTLS_MD_NONE, this must match the output length of the corresponding hash algorithm.
hash	The buffer holding the message digest or raw data. This must be a readable buffer of at least `hashlen` Bytes.
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.

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

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

Note: The hash_id set in ctx by calling mbedtls_rsa_set_padding() selects the hash used for the encoding operation and for the mask generation function (MGF1). For more details on the encoding operation and the mask generation function, consult RFC-3447: Public-Key Cryptography Standards (PKCS) #1 v2.1: RSA Cryptography Specifications.; This function enforces that the provided salt length complies with FIPS 186-4 §5.5 (e) and RFC 8017 (PKCS#1 v2.2) §9.1.1 step 3. The constraint is that the hash length plus the salt length plus 2 bytes must be at most the key length. If this constraint is not met, this function returns MBEDTLS_ERR_RSA_BAD_INPUT_DATA.

Parameters

ctx	The initialized RSA context to use.
f_rng	The RNG function. It is mandatory and 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.
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 or raw data in Bytes. If `md_alg` is not MBEDTLS_MD_NONE, this must match the output length of the corresponding hash algorithm.
hash	The buffer holding the message digest or raw data. This must be a readable buffer of at least `hashlen` Bytes.
saltlen	The length of the salt that should be used. If passed MBEDTLS_RSA_SALT_LEN_ANY, the function will use the largest possible salt length up to the hash length, which is the largest permitted by some standards including FIPS 186-4 §5.5.
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.

int mbedtls_rsa_rsassa_pss_verify	(	mbedtls_rsa_context *	ctx,
		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).

Note: The hash_id set in ctx by calling mbedtls_rsa_set_padding() selects the hash used for the encoding operation and for the mask generation function (MGF1). For more details on the encoding operation and the mask generation function, consult RFC-3447: Public-Key Cryptography Standards (PKCS) #1 v2.1: RSA Cryptography Specifications. If the hash_id set in ctx by mbedtls_rsa_set_padding() is MBEDTLS_MD_NONE, the md_alg parameter is used.

Parameters

ctx	The initialized RSA public key context to use.
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 or raw data in Bytes. If `md_alg` is not MBEDTLS_MD_NONE, this must match the output length of the corresponding hash algorithm.
hash	The buffer holding the message digest or raw data. This must be a readable buffer of at least `hashlen` Bytes.
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.

int mbedtls_rsa_rsassa_pss_verify_ext	(	mbedtls_rsa_context *	ctx,
		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).

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 set in ctx by mbedtls_rsa_set_padding() is ignored.

Parameters

ctx	The initialized RSA public key context to use.
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 or raw data in Bytes. If `md_alg` is not MBEDTLS_MD_NONE, this must match the output length of the corresponding hash algorithm.
hash	The buffer holding the message digest or raw data. This must be a readable buffer of at least `hashlen` Bytes.
mgf1_hash_id	The message digest algorithm used for the verification operation and the mask generation function (MGF1). For more details on the encoding operation and the mask generation function, consult RFC-3447: Public-Key Cryptography Standards (PKCS) #1 v2.1: RSA Cryptography Specifications.
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.

int mbedtls_rsa_self_test ( int verbose )

The RSA checkup routine.

Returns: 0 on success.; 1 on failure.

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

This function sets padding for an already initialized 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 mbedtls_rsa_rsaes_xxx or mbedtls_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 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 hash identifier for PSS or OAEP, if `padding` is MBEDTLS_RSA_PKCS_V21. MBEDTLS_MD_NONE is accepted by this function but may be not suitable for some operations. Ignored if `padding` is MBEDTLS_RSA_PKCS_V15.

Returns: 0 on success.; MBEDTLS_ERR_RSA_INVALID_PADDING failure: padding or hash_id is invalid.

Macros

Functions

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Macro Definition Documentation

Function Documentation