mbx_rsa_private_crt

Performs the private key RSA decryption operation.

Syntax

mbx_status mbx_rsa_private_crt_mb8(const int8u* const from_pa[8], int8u* const to_pa[8], const int64u* const p_pa[8], const int64u* const q_pa[8], const int64u* const dp_pa[8], const int64u* const dq_pa[8], const int64u* const iq_pa[8], int rsaBitlen, const mbx_RSA_Method* m, int8u* pBuffer);

mbx_status mbx_rsa_private_crt_ssl_mb8(const int8u* const from_pa[8], int8u* const to_pa[8], const BIGNUM* const p_pa[8], const BIGNUM* const q_pa[8], const BIGNUM* const dp_pa[8], const BIGNUM* const dq_pa[8], const BIGNUM* const iq_pa[8], int rsaBitlen);

Include Files

crypto_mb/rsa.h

Parameters

from_pa

Array of pointers to the ciphertext data vectors.

to_pa

Array of pointers to the recovered data vectors.

p_pa

Array of pointers to the p-prime factor vectors of RSA moduli.

q_pa

Array of pointers to the q-prime factor vectors of RSA moduli.

dp_pa

Array of pointers to the p’s CRT private exponent vectors.

dq_pa

Array of pointers to the q’s CRT private exponent vectors.

iq_pa

Array of pointers to CRT coefficient (multiplicative inversion of q with respect to p) vectors.

rsaBitLen

Size of RSAs moduli in bits.

m

Pointer to the pre-defined data structure specified by the RSA encryption operation.

pBuffer

Pointer to the work buffer.

Description

The mbx_rsa_private_crt() function performs independent CRT-based RSA private key operations using RSAprivate key in a quintuple form - private factors (p and q), privateexponents (dp and dq) and CRT coefficient invq. The factors are passed through p_pa and q_pa, exponents are passed though dp_pa and dq_pa and CRT coefficients are passed through iq_pa parameter. The size of RSAs factors, private exponents and CRT coefficients must be the same and equal to rsaBitlen/2 bits. The function decrypts ciphertexts specified by the from_pa parameter in parallel, and stores recovered ciphertexts in the memory locations specified by the to_pa parameter. Memory buffers of the plain- and ciphertext must be ceil(rsaBitlen/8) bytes length.

At the moment, RSA-10024, RSA-2048, RSA-3072and RSA-4096 are supported only. If m is NULL, the functionuses mbx_RSA_private_crt_Method(rsaBitsize). If m is not NULL, it must be assigned toeither mbx_RSA1K_ private_crt_Method(), mbx_RSA2K_ private_crt_Method(), mbx_RSA3K_ private_crt_Method() or mbx_RSA4K_ private_crt_Method() and match to rsaBitlen value.

If pBuffer is NULL, then the function allocated a work buffer of suitable size dynamically. Anallocated buffer will be released before the function return. If the workbuffer is allocated in the application, it affects performancepositively. Thembx_RSA_Method_BufSize() function returns the size of the work buffer requiredfor the operation.

The function itself does not support any kind of padding. The application is responsible for the padding if it is required.

Note

The mbx_rsa_private_crt_ssl() function is the “twin” of mbx_rsa_private_crt() one. Itacts the same. The basic difference in comparison withmbx_rsa_private() is the representation of RSA key stuff. mbx_rsa_private_crt_ssl uses BIGNUM datatype insteadof vector.

Return Values

The mbx_rsa_private_crt() function returns the status that indicates whether the operation completed successfully or not. The status value of 0 indicates that all operations completed successfully. The error condition can be analyzed by the MBX_GET_STS() call.