ST25TAGS_TVC_OpenSecuritySession Fails when trying to open a CONFIGURATION_SECURITY_SESSION

[AC_E]

Hello ST Community,

I am using a STEVAL-25R200A to do tests with the ST25TV02KC.

I am trying to rfalST25xVPollerPresentPassword, with a pwdNumber of 0x00 to enter Configuration Session (As described in the nfc tag datasheet), But keep getting error 5, even though I am passing the default 32-bit password.
I am using this function:

ReturnCode ST25TAGS_TVC_OpenSecuritySession(const uint8_t * uid, ST25TAG_TVC_SecuritySession_t sessionType,
 const uint8_t * pPassword)
{
 uint8_t pwdNumber;
 uint8_t pwdLengthInBytes = 4;
 ReturnCode errCode;
 uint8_t rxBuf[ 1 + 2 + 2 ]; /* Flags + Random Number Data + CRC */;
 uint16_t rcvLen;
 uint8_t updatedPassword[8];

 switch (sessionType)
 {
 case CONFIGURATION_SECURITY_SESSION:
 pwdNumber = 0;
 break;
 case USER_AREA1_SECURITY_SESSION:
 pwdNumber = 1;
 break;
 case USER_AREA2_SECURITY_SESSION:
 pwdNumber = 2;
 break;
 case SINGLE_USER_AREA_SECURITY_SESSION:
 pwdLengthInBytes = 8;
 pwdNumber = 1;
 break;
 case UNTRACEABLE_SECURITY_SESSION:
 pwdNumber = 3;
 break;
 default:
 return RFAL_ERR_PARAM;
 }

 // Encrypt password
 // 1. Get Random Number
 errCode = rfalST25xVPollerGetRandomNumber( ST25TAGS_TVC_REQ_FLAG, uid, rxBuf, sizeof(rxBuf), &rcvLen );

 if ( errCode == RFAL_ERR_NONE )
 {
 // 2. XOR random number with given password located in rxBuf[1] and rxBuf[2]
 for (uint8_t i = 0; i < (pwdLengthInBytes * 2); i++)
 {
 updatedPassword[i] = pPassword[i] ^ rxBuf[2 - (i + 1) % 2];
 }

 // Present password
 errCode = rfalST25xVPollerPresentPassword( ST25TAGS_TVC_REQ_FLAG, uid,
 pwdNumber, updatedPassword, pwdLengthInBytes);
 }

 // Same ReturnCode definitions used in st_errno.h of RFAL
 return errCode;
}

And calling it like this:

uint8_t plainPwd[4] = {0x0, 0x0, 0x0 ,0x0}; 
err = ST25TAGS_TVC_OpenSecuritySession(uid, CONFIGURATION_SECURITY_SESSION, plainPwd);
platformLog(" Present password: %s Error Code: %d \r\n", (err != RFAL_ERR_NONE) ? "Fail" : "OK", (err != RFAL_ERR_NONE) ? err : 0);

But i get this error code:
Present password: Fail Error Code: 5

I would appreciate your help,

Thank you 

[Ulysses HERNIOSUS]

Hi, 

the functions returns RFAL_ERR_REQUEST. Reason is typically an error code returned by the tag. In rfalNfcvParseError()  this is being parsed and transformed to error codes. Best to put there a breakpoint and compare the received data against the ST25TVC DS.

BR, Ulysses