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Algorithms - PKCS7

Functions

Name
int wc_PKCS7_InitWithCert(PKCS7 * pkcs7, byte * cert, word32 certSz)
This function initializes a PKCS7 structure with a DER-formatted certificate. To initialize an empty PKCS7 structure, one can pass in a NULL cert and 0 for certSz.
void wc_PKCS7_Free(PKCS7 * pkcs7)
This function releases any memory allocated by a PKCS7 initializer.
int wc_PKCS7_EncodeData(PKCS7 * pkcs7, byte * output, word32 outputSz)
This function builds the PKCS7 data content type, encoding the PKCS7 structure into a buffer containing a parsable PKCS7 data packet.
int wc_PKCS7_EncodeSignedData(PKCS7 * pkcs7, byte * output, word32 outputSz)
This function builds the PKCS7 signed data content type, encoding the PKCS7 structure into a buffer containing a parsable PKCS7 signed data packet.
int wc_PKCS7_EncodeSignedData_ex(PKCS7 * pkcs7, const byte * hashBuf, word32 hashSz, byte * outputHead, word32 * outputHeadSz, byte * outputFoot, word32 * outputFootSz)
This function builds the PKCS7 signed data content type, encoding the PKCS7 structure into a header and footer buffer containing a parsable PKCS7 signed data packet. This does not include the content. A hash must be computed and provided for the data.
int wc_PKCS7_VerifySignedData(PKCS7 * pkcs7, byte * pkiMsg, word32 pkiMsgSz)
This function takes in a transmitted PKCS7 signed data message, extracts the certificate list and certificate revocation list, and then verifies the signature. It stores the extracted content in the given PKCS7 structure.
int wc_PKCS7_VerifySignedData_ex(PKCS7 * pkcs7, const byte * hashBuf, word32 hashSz, byte * pkiMsgHead, word32 pkiMsgHeadSz, byte * pkiMsgFoot, word32 pkiMsgFootSz)
This function takes in a transmitted PKCS7 signed data message as hash/header/footer, then extracts the certificate list and certificate revocation list, and then verifies the signature. It stores the extracted content in the given PKCS7 structure.
int wc_PKCS7_EncodeEnvelopedData(PKCS7 * pkcs7, byte * output, word32 outputSz)
This function builds the PKCS7 enveloped data content type, encoding the PKCS7 structure into a buffer containing a parsable PKCS7 enveloped data packet.
int wc_PKCS7_DecodeEnvelopedData(PKCS7 * pkcs7, byte * pkiMsg, word32 pkiMsgSz, byte * output, word32 outputSz)
This function unwraps and decrypts a PKCS7 enveloped data content type, decoding the message into output. It uses the private key of the PKCS7 object passed in to decrypt the message.

Functions Documentation

function wc_PKCS7_InitWithCert

int wc_PKCS7_InitWithCert(
    PKCS7 * pkcs7,
    byte * cert,
    word32 certSz
)

This function initializes a PKCS7 structure with a DER-formatted certificate. To initialize an empty PKCS7 structure, one can pass in a NULL cert and 0 for certSz.

Parameters:

  • pkcs7 pointer to the PKCS7 structure in which to store the decoded cert
  • cert pointer to a buffer containing a DER formatted ASN.1 certificate with which to initialize the PKCS7 structure
  • certSz size of the certificate buffer

See: wc_PKCS7_Free

Return:

  • 0 Returned on successfully initializing the PKCS7 structure
  • MEMORY_E Returned if there is an error allocating memory with XMALLOC
  • ASN_PARSE_E Returned if there is an error parsing the cert header
  • ASN_OBJECT_ID_E Returned if there is an error parsing the encryption type from the cert
  • ASN_EXPECT_0_E Returned if there is a formatting error in the encryption specification of the cert file
  • ASN_BEFORE_DATE_E Returned if the date is before the certificate start date
  • ASN_AFTER_DATE_E Returned if the date is after the certificate expiration date
  • ASN_BITSTR_E Returned if there is an error parsing a bit string from the certificate
  • ECC_CURVE_OID_E Returned if there is an error parsing the ECC key from the certificate
  • ASN_UNKNOWN_OID_E Returned if the certificate is using an unknown key object id
  • ASN_VERSION_E Returned if the ALLOW_V1_EXTENSIONS option is not defined and the certificate is a V1 or V2 certificate
  • BAD_FUNC_ARG Returned if there is an error processing the certificate extension
  • ASN_CRIT_EXT_E Returned if an unfamiliar critical extension is encountered in processing the certificate
  • ASN_SIG_OID_E Returned if the signature encryption type is not the same as the encryption type of the certificate in the provided file
  • ASN_SIG_CONFIRM_E Returned if confirming the certification signature fails
  • ASN_NAME_INVALID_E Returned if the certificate’s name is not permitted by the CA name constraints
  • ASN_NO_SIGNER_E Returned if there is no CA signer to verify the certificate’s authenticity

Example

PKCS7 pkcs7;
byte derBuff[] = { }; // initialize with DER-encoded certificate
if ( wc_PKCS7_InitWithCert(&pkcs7, derBuff, sizeof(derBuff)) != 0 ) {
    // error parsing certificate into pkcs7 format
}

function wc_PKCS7_Free

void wc_PKCS7_Free(
    PKCS7 * pkcs7
)

This function releases any memory allocated by a PKCS7 initializer.

Parameters:

  • pkcs7 pointer to the PKCS7 structure to free

See: wc_PKCS7_InitWithCert

Return: none No returns.

Example

PKCS7 pkcs7;
// initialize and use PKCS7 object

wc_PKCS7_Free(pkcs7);

function wc_PKCS7_EncodeData

int wc_PKCS7_EncodeData(
    PKCS7 * pkcs7,
    byte * output,
    word32 outputSz
)

This function builds the PKCS7 data content type, encoding the PKCS7 structure into a buffer containing a parsable PKCS7 data packet.

Parameters:

  • pkcs7 pointer to the PKCS7 structure to encode
  • output pointer to the buffer in which to store the encoded certificate
  • outputSz size available in the output buffer

See: wc_PKCS7_InitWithCert

Return:

  • Success On successfully encoding the PKCS7 data into the buffer, returns the index parsed up to in the PKCS7 structure. This index also corresponds to the bytes written to the output buffer.
  • BUFFER_E Returned if the given buffer is not large enough to hold the encoded certificate

Example

PKCS7 pkcs7;
int ret;

byte derBuff[] = { }; // initialize with DER-encoded certificate
byte pkcs7Buff[FOURK_BUF];

wc_PKCS7_InitWithCert(&pkcs7, derBuff, sizeof(derBuff));
// update message and data to encode
pkcs7.privateKey = key;
pkcs7.privateKeySz = keySz;
pkcs7.content = data;
pkcs7.contentSz = dataSz;
... etc.

ret = wc_PKCS7_EncodeData(&pkcs7, pkcs7Buff, sizeof(pkcs7Buff));
if ( ret != 0 ) {
    // error encoding into output buffer
}

function wc_PKCS7_EncodeSignedData

int wc_PKCS7_EncodeSignedData(
    PKCS7 * pkcs7,
    byte * output,
    word32 outputSz
)

This function builds the PKCS7 signed data content type, encoding the PKCS7 structure into a buffer containing a parsable PKCS7 signed data packet.

Parameters:

  • pkcs7 pointer to the PKCS7 structure to encode
  • output pointer to the buffer in which to store the encoded certificate
  • outputSz size available in the output buffer

See:

Return:

  • Success On successfully encoding the PKCS7 data into the buffer, returns the index parsed up to in the PKCS7 structure. This index also corresponds to the bytes written to the output buffer.
  • BAD_FUNC_ARG Returned if the PKCS7 structure is missing one or more required elements to generate a signed data packet
  • MEMORY_E Returned if there is an error allocating memory
  • PUBLIC_KEY_E Returned if there is an error parsing the public key
  • RSA_BUFFER_E Returned if buffer error, output too small or input too large
  • BUFFER_E Returned if the given buffer is not large enough to hold the encoded certificate
  • MP_INIT_E may be returned if there is an error generating the signature
  • MP_READ_E may be returned if there is an error generating the signature
  • MP_CMP_E may be returned if there is an error generating the signature
  • MP_INVMOD_E may be returned if there is an error generating the signature
  • MP_EXPTMOD_E may be returned if there is an error generating the signature
  • MP_MOD_E may be returned if there is an error generating the signature
  • MP_MUL_E may be returned if there is an error generating the signature
  • MP_ADD_E may be returned if there is an error generating the signature
  • MP_MULMOD_E may be returned if there is an error generating the signature
  • MP_TO_E may be returned if there is an error generating the signature
  • MP_MEM may be returned if there is an error generating the signature

Example

PKCS7 pkcs7;
int ret;

byte data[] = {}; // initialize with data to sign
byte derBuff[] = { }; // initialize with DER-encoded certificate
byte pkcs7Buff[FOURK_BUF];

wc_PKCS7_InitWithCert(&pkcs7, derBuff, sizeof(derBuff));
// update message and data to encode
pkcs7.privateKey = key;
pkcs7.privateKeySz = keySz;
pkcs7.content = data;
pkcs7.contentSz = dataSz;
pkcs7.hashOID = SHAh;
pkcs7.rng = &rng;
... etc.

ret = wc_PKCS7_EncodeSignedData(&pkcs7, pkcs7Buff, sizeof(pkcs7Buff));
if ( ret != 0 ) {
    // error encoding into output buffer
}

wc_PKCS7_Free(&pkcs7);

function wc_PKCS7_EncodeSignedData_ex

int wc_PKCS7_EncodeSignedData_ex(
    PKCS7 * pkcs7,
    const byte * hashBuf,
    word32 hashSz,
    byte * outputHead,
    word32 * outputHeadSz,
    byte * outputFoot,
    word32 * outputFootSz
)

This function builds the PKCS7 signed data content type, encoding the PKCS7 structure into a header and footer buffer containing a parsable PKCS7 signed data packet. This does not include the content. A hash must be computed and provided for the data.

Parameters:

  • pkcs7 pointer to the PKCS7 structure to encode
  • hashBuf pointer to computed hash for the content data
  • hashSz size of the digest
  • outputHead pointer to the buffer in which to store the encoded certificate header
  • outputHeadSz pointer populated with size of output header buffer and returns actual size
  • outputFoot pointer to the buffer in which to store the encoded certificate footer
  • outputFootSz pointer populated with size of output footer buffer and returns actual size

See:

Return:

  • 0=Success
  • BAD_FUNC_ARG Returned if the PKCS7 structure is missing one or more required elements to generate a signed data packet
  • MEMORY_E Returned if there is an error allocating memory
  • PUBLIC_KEY_E Returned if there is an error parsing the public key
  • RSA_BUFFER_E Returned if buffer error, output too small or input too large
  • BUFFER_E Returned if the given buffer is not large enough to hold the encoded certificate
  • MP_INIT_E may be returned if there is an error generating the signature
  • MP_READ_E may be returned if there is an error generating the signature
  • MP_CMP_E may be returned if there is an error generating the signature
  • MP_INVMOD_E may be returned if there is an error generating the signature
  • MP_EXPTMOD_E may be returned if there is an error generating the signature
  • MP_MOD_E may be returned if there is an error generating the signature
  • MP_MUL_E may be returned if there is an error generating the signature
  • MP_ADD_E may be returned if there is an error generating the signature
  • MP_MULMOD_E may be returned if there is an error generating the signature
  • MP_TO_E may be returned if there is an error generating the signature
  • MP_MEM may be returned if there is an error generating the signature

Example

PKCS7 pkcs7;
int ret;
byte derBuff[] = { }; // initialize with DER-encoded certificate
byte data[] = {}; // initialize with data to sign
byte pkcs7HeadBuff[FOURK_BUF/2];
byte pkcs7FootBuff[FOURK_BUF/2];
word32 pkcs7HeadSz = (word32)sizeof(pkcs7HeadBuff);
word32 pkcs7FootSz = (word32)sizeof(pkcs7HeadBuff);
enum wc_HashType hashType = WC_HASH_TYPE_SHA;
byte   hashBuf[WC_MAX_DIGEST_SIZE];
word32 hashSz = wc_HashGetDigestSize(hashType);

wc_PKCS7_InitWithCert(&pkcs7, derBuff, sizeof(derBuff));
// update message and data to encode
pkcs7.privateKey = key;
pkcs7.privateKeySz = keySz;
pkcs7.content = NULL;
pkcs7.contentSz = dataSz;
pkcs7.hashOID = SHAh;
pkcs7.rng = &rng;
... etc.

// calculate hash for content
ret = wc_HashInit(&hash, hashType);
if (ret == 0) {
    ret = wc_HashUpdate(&hash, hashType, data, sizeof(data));
    if (ret == 0) {
        ret = wc_HashFinal(&hash, hashType, hashBuf);
    }
    wc_HashFree(&hash, hashType);
}

ret = wc_PKCS7_EncodeSignedData_ex(&pkcs7, hashBuf, hashSz, pkcs7HeadBuff, 
    &pkcs7HeadSz, pkcs7FootBuff, &pkcs7FootSz);
if ( ret != 0 ) {
    // error encoding into output buffer
}

wc_PKCS7_Free(&pkcs7);

function wc_PKCS7_VerifySignedData

int wc_PKCS7_VerifySignedData(
    PKCS7 * pkcs7,
    byte * pkiMsg,
    word32 pkiMsgSz
)

This function takes in a transmitted PKCS7 signed data message, extracts the certificate list and certificate revocation list, and then verifies the signature. It stores the extracted content in the given PKCS7 structure.

Parameters:

  • pkcs7 pointer to the PKCS7 structure in which to store the parsed certificates
  • pkiMsg pointer to the buffer containing the signed message to verify and decode
  • pkiMsgSz size of the signed message

See:

Return:

  • 0 Returned on successfully extracting the information from the message
  • BAD_FUNC_ARG Returned if one of the input parameters is invalid
  • ASN_PARSE_E Returned if there is an error parsing from the given pkiMsg
  • PKCS7_OID_E Returned if the given pkiMsg is not a signed data type
  • ASN_VERSION_E Returned if the PKCS7 signer info is not version 1
  • MEMORY_E Returned if there is an error allocating memory
  • PUBLIC_KEY_E Returned if there is an error parsing the public key
  • RSA_BUFFER_E Returned if buffer error, output too small or input too large
  • BUFFER_E Returned if the given buffer is not large enough to hold the encoded certificate
  • MP_INIT_E may be returned if there is an error generating the signature
  • MP_READ_E may be returned if there is an error generating the signature
  • MP_CMP_E may be returned if there is an error generating the signature
  • MP_INVMOD_E may be returned if there is an error generating the signature
  • MP_EXPTMOD_E may be returned if there is an error generating the signature
  • MP_MOD_E may be returned if there is an error generating the signature
  • MP_MUL_E may be returned if there is an error generating the signature
  • MP_ADD_E may be returned if there is an error generating the signature
  • MP_MULMOD_E may be returned if there is an error generating the signature
  • MP_TO_E may be returned if there is an error generating the signature
  • MP_MEM may be returned if there is an error generating the signature

Example

PKCS7 pkcs7;
int ret;
byte pkcs7Buff[] = {}; // the PKCS7 signature

wc_PKCS7_InitWithCert(&pkcs7, NULL, 0);
// update message and data to encode
pkcs7.privateKey = key;
pkcs7.privateKeySz = keySz;
pkcs7.content = data;
pkcs7.contentSz = dataSz;
... etc.

ret = wc_PKCS7_VerifySignedData(&pkcs7, pkcs7Buff, sizeof(pkcs7Buff));
if ( ret != 0 ) {
    // error encoding into output buffer
}

wc_PKCS7_Free(&pkcs7);

function wc_PKCS7_VerifySignedData_ex

int wc_PKCS7_VerifySignedData_ex(
    PKCS7 * pkcs7,
    const byte * hashBuf,
    word32 hashSz,
    byte * pkiMsgHead,
    word32 pkiMsgHeadSz,
    byte * pkiMsgFoot,
    word32 pkiMsgFootSz
)

This function takes in a transmitted PKCS7 signed data message as hash/header/footer, then extracts the certificate list and certificate revocation list, and then verifies the signature. It stores the extracted content in the given PKCS7 structure.

Parameters:

  • pkcs7 pointer to the PKCS7 structure in which to store the parsed certificates
  • hashBuf pointer to computed hash for the content data
  • hashSz size of the digest
  • pkiMsgHead pointer to the buffer containing the signed message header to verify and decode
  • pkiMsgHeadSz size of the signed message header
  • pkiMsgFoot pointer to the buffer containing the signed message footer to verify and decode
  • pkiMsgFootSz size of the signed message footer

See:

Return:

  • 0 Returned on successfully extracting the information from the message
  • BAD_FUNC_ARG Returned if one of the input parameters is invalid
  • ASN_PARSE_E Returned if there is an error parsing from the given pkiMsg
  • PKCS7_OID_E Returned if the given pkiMsg is not a signed data type
  • ASN_VERSION_E Returned if the PKCS7 signer info is not version 1
  • MEMORY_E Returned if there is an error allocating memory
  • PUBLIC_KEY_E Returned if there is an error parsing the public key
  • RSA_BUFFER_E Returned if buffer error, output too small or input too large
  • BUFFER_E Returned if the given buffer is not large enough to hold the encoded certificate
  • MP_INIT_E may be returned if there is an error generating the signature
  • MP_READ_E may be returned if there is an error generating the signature
  • MP_CMP_E may be returned if there is an error generating the signature
  • MP_INVMOD_E may be returned if there is an error generating the signature
  • MP_EXPTMOD_E may be returned if there is an error generating the signature
  • MP_MOD_E may be returned if there is an error generating the signature
  • MP_MUL_E may be returned if there is an error generating the signature
  • MP_ADD_E may be returned if there is an error generating the signature
  • MP_MULMOD_E may be returned if there is an error generating the signature
  • MP_TO_E may be returned if there is an error generating the signature
  • MP_MEM may be returned if there is an error generating the signature

Example

PKCS7 pkcs7;
int ret;
byte data[] = {}; // initialize with data to sign
byte pkcs7HeadBuff[] = {}; // initialize with PKCS7 header
byte pkcs7FootBuff[] = {}; // initialize with PKCS7 footer
enum wc_HashType hashType = WC_HASH_TYPE_SHA;
byte   hashBuf[WC_MAX_DIGEST_SIZE];
word32 hashSz = wc_HashGetDigestSize(hashType);

wc_PKCS7_InitWithCert(&pkcs7, NULL, 0);
// update message and data to encode
pkcs7.privateKey = key;
pkcs7.privateKeySz = keySz;
pkcs7.content = NULL;
pkcs7.contentSz = dataSz;
pkcs7.rng = &rng;
... etc.

// calculate hash for content
ret = wc_HashInit(&hash, hashType);
if (ret == 0) {
    ret = wc_HashUpdate(&hash, hashType, data, sizeof(data));
    if (ret == 0) {
        ret = wc_HashFinal(&hash, hashType, hashBuf);
    }
    wc_HashFree(&hash, hashType);
}

ret = wc_PKCS7_VerifySignedData_ex(&pkcs7, hashBuf, hashSz, pkcs7HeadBuff, 
    sizeof(pkcs7HeadBuff), pkcs7FootBuff, sizeof(pkcs7FootBuff));
if ( ret != 0 ) {
    // error encoding into output buffer
}

wc_PKCS7_Free(&pkcs7);

function wc_PKCS7_EncodeEnvelopedData

int wc_PKCS7_EncodeEnvelopedData(
    PKCS7 * pkcs7,
    byte * output,
    word32 outputSz
)

This function builds the PKCS7 enveloped data content type, encoding the PKCS7 structure into a buffer containing a parsable PKCS7 enveloped data packet.

Parameters:

  • pkcs7 pointer to the PKCS7 structure to encode
  • output pointer to the buffer in which to store the encoded certificate
  • outputSz size available in the output buffer

See:

Return:

  • Success Returned on successfully encoding the message in enveloped data format, returns the size written to the output buffer
  • BAD_FUNC_ARG: Returned if one of the input parameters is invalid, or if the PKCS7 structure is missing required elements
  • ALGO_ID_E Returned if the PKCS7 structure is using an unsupported algorithm type. Currently, only DESb and DES3b are supported
  • BUFFER_E Returned if the given output buffer is too small to store the output data
  • MEMORY_E Returned if there is an error allocating memory
  • RNG_FAILURE_E Returned if there is an error initializing the random number generator for encryption
  • DRBG_FAILED Returned if there is an error generating numbers with the random number generator used for encryption

Example

PKCS7 pkcs7;
int ret;

byte derBuff[] = { }; // initialize with DER-encoded certificate
byte pkcs7Buff[FOURK_BUF];

wc_PKCS7_InitWithCert(&pkcs7, derBuff, sizeof(derBuff));
// update message and data to encode
pkcs7.privateKey = key;
pkcs7.privateKeySz = keySz;
pkcs7.content = data;
pkcs7.contentSz = dataSz;
... etc.

ret = wc_PKCS7_EncodeEnvelopedData(&pkcs7, pkcs7Buff, sizeof(pkcs7Buff));
if ( ret != 0 ) {
    // error encoding into output buffer
}

function wc_PKCS7_DecodeEnvelopedData

int wc_PKCS7_DecodeEnvelopedData(
    PKCS7 * pkcs7,
    byte * pkiMsg,
    word32 pkiMsgSz,
    byte * output,
    word32 outputSz
)

This function unwraps and decrypts a PKCS7 enveloped data content type, decoding the message into output. It uses the private key of the PKCS7 object passed in to decrypt the message.

Parameters:

  • pkcs7 pointer to the PKCS7 structure containing the private key with which to decode the enveloped data package
  • pkiMsg pointer to the buffer containing the enveloped data package
  • pkiMsgSz size of the enveloped data package
  • output pointer to the buffer in which to store the decoded message
  • outputSz size available in the output buffer

See:

Return:

  • On successfully extracting the information from the message, returns the bytes written to output
  • BAD_FUNC_ARG Returned if one of the input parameters is invalid
  • ASN_PARSE_E Returned if there is an error parsing from the given pkiMsg
  • PKCS7_OID_E Returned if the given pkiMsg is not an enveloped data type
  • ASN_VERSION_E Returned if the PKCS7 signer info is not version 0
  • MEMORY_E Returned if there is an error allocating memory
  • ALGO_ID_E Returned if the PKCS7 structure is using an unsupported algorithm type. Currently, only DESb and DES3b are supported for encryption, with RSAk for signature generation
  • PKCS7_RECIP_E Returned if there is no recipient found in the enveloped data that matches the recipient provided
  • RSA_BUFFER_E Returned if there is an error during RSA signature verification due to buffer error, output too small or input too large.
  • MP_INIT_E may be returned if there is an error during signature verification
  • MP_READ_E may be returned if there is an error during signature verification
  • MP_CMP_E may be returned if there is an error during signature verification
  • MP_INVMOD_E may be returned if there is an error during signature verification
  • MP_EXPTMOD_E may be returned if there is an error during signature verification
  • MP_MOD_E may be returned if there is an error during signature verification
  • MP_MUL_E may be returned if there is an error during signature verification
  • MP_ADD_E may be returned if there is an error during signature verification
  • MP_MULMOD_E may be returned if there is an error during signature verification
  • MP_TO_E may be returned if there is an error during signature verification
  • MP_MEM may be returned if there is an error during signature verification

Example

PKCS7 pkcs7;
byte received[] = { }; // initialize with received enveloped message
byte decoded[FOURK_BUF];
int decodedSz;

// initialize pkcs7 with certificate
// update key
pkcs7.privateKey = key;
pkcs7.privateKeySz = keySz;

decodedSz = wc_PKCS7_DecodeEnvelopedData(&pkcs7, received,
sizeof(received),decoded, sizeof(decoded));
if ( decodedSz != 0 ) {
    // error decoding message
}

Updated on 2022-05-18 at 08:30:58 +0000