tc_ccm_decryption_verification() function

CCM decryption and tag verification procedure @note: out buffer should be at least (plen - c->mlen) bytes long. @note: The sequence b for encryption is formatted as follows: b = [FLAGS | nonce | counter ], where: FLAGS is 1 byte long nonce is 13 bytes long counter is 2 bytes long The byte FLAGS is composed by the following 8 bits: 0-2 bits: used to represent the value of q-1 3-7 btis: always 0's @note: The sequence b for authentication is formatted as follows: b = [FLAGS | nonce | length(mac length)], where: FLAGS is 1 byte long nonce is 13 bytes long length(mac length) is 2 bytes long The byte FLAGS is composed by the following 8 bits: 0-2 bits: used to represent the value of q-1 3-5 bits: mac length (encoded as: (mlen-2)/2) 6: Adata (0 if alen == 0, and 1 otherwise) 7: always 0

Syntax

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Summary

Declaration

Definition

from ccm_mode.h:202

int tc_ccm_decryption_verification(uint8_t *out, unsigned int olen, const uint8_t *associated_data, unsigned int alen, const uint8_t *payload, unsigned int plen, TCCcmMode_t c);

Implemented in ccm_mode.c:198

Arguments

Argument

Declared as

Description

out

uint8_t *

OUT -- decrypted data

olen

unsigned int

associated_data

const uint8_t *

IN -- associated data

alen

unsigned int

IN -- associated data length in bytes

payload

const uint8_t *

IN -- payload

plen

unsigned int

IN -- payload length in bytes

TCCcmMode_t

IN -- CCM state

Return value

returns TC_CRYPTO_SUCCESS (1) returns TC_CRYPTO_FAIL (0) if: out == NULL or c == NULL or ((plen > 0) and (payload == NULL)) or ((alen > 0) and (associated_data == NULL)) or (alen >= TC_CCM_AAD_MAX_BYTES) or (plen >= TC_CCM_PAYLOAD_MAX_BYTES) or (olen mlen)