CodeScopeSTM32 Libraries and SamplesmbedTLSmbedtls_rsa_export_raw()

mbedtls_rsa_export_raw() function

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 \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: 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 P, \p Q from \p N, \p D, and \p 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.

Syntax

from rsa.h:372

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 );

Arguments

ctx

The initialized RSA context.

N

The Byte array to store the RSA modulus, or \c 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 \p N, or \c 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 \p N, or \c 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 \c 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 \c NULL if this field need not be exported.

E_len

The size of the buffer for the public exponent.

Return value

\c 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.

Notes

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

References

Location	Text
rsa.h:372	int mbedtls_rsa_export_raw( const mbedtls_rsa_context *ctx,