NAME

CSSM_DecryptData

SYNOPSIS

CSSM_RETURN CSSMAPI CSSM_DecryptData
    (CSSM_CC_HANDLE CCHandle,
    const CSSM_DATA_PTR CipherBufs,
    uint32 CipherBufCount,
    CSSM_DATA_PTR ClearBufs,
    uint32 ClearBufCount,
    uint32 *bytesDecrypted,
    CSSM_DATA_PTR RemData)

DESCRIPTION

This function decrypts the supplied encrypted data. The CSSM_QuerySize function can be used to estimate the output buffer size required.

PARAMETERS

CCHandle (input)

The handle that describes the context of this cryptographic operation used to link to the CSP-managed information.

CipherBufs (input)

A pointer to a vector of CSSM_DATA structures that contain the data to be operated on.

CipherBufCount (input)

The number of CipherBufs.

ClearBufs (output)

A pointer to a vector of CSSM_DATA structures that contain the decrypted data resulting from the decryption operation.

ClearBufCount (input)

The number of ClearBufs.

BytesDecrypted (output)

A pointer to uint32 for the size of the decrypted data in bytes.

RemData (output)

A pointer to the CSSM_DATA structure for the last decrypted block.

RETURN VALUE

A CSSM return value. This function returns CSSM_OK if successful, and returns an error code if an error has occurred.

ERRORS

CSSM_CSP_INVALID_CONTEXT_HANDLE

Invalid context handle.

CSSM_CSP_INVALID_CONTEXT

Context type and operation do not match.

CSSM_CSP_INVALID_DATA_POINTER

Invalid input or output CSSM_DATA pointer.

CSSM_CSP_INVALID_DATA_COUNT

Invalid data count; data count cannot be 0.

CSSM_CSP_INVALID_DATA

Invalid output CSSM_DATA buffer.

CSSM_CSP_NOT_ENOUGH_BUFFER

The output buffer is not big enough.

CSSM_CSP_INVALID_ALGORITHM

Unknown algorithm.

CSSM_CSP_MEMORY_ERROR

Not enough memory to allocate.

CSSM_CSP_OPERATION_UNSUPPORTED

Decrypt data service not supported.

CSSM_CSP_OPERATION_FAILED

Cryptographic operation failed.

CSSM_CSP_VECTOROFBUFS_UNSUPPORTED

Supports only a single buffer of input.

CSSM_CSP_INVALID_ATTR_KEY

Invalid or missing key attribute in the context.

CSSM_CSP_INVALID_KEY

Invalid or missing key data in the context attribute.

CSSM_CSP_INVALID_KEYCLASS

Key class is not private or public key class for asymmetric context or is not session class for symmetric context.

CSSM_CSP_KEY_USAGE_INCORRECT

Key usage does not allow decryption.

CSSM_CSP_KEY_ALGID_MISMATCH

The supplied key does not match the operation.

CSSM_CSP_KEY_KEYHEADER_INCONSISTENT

Key header and key data is inconsistent.

CSSM_CSP_KEY_FORMAT_INCORRECT

Unknown key format.

CSSM_CSP_INVALID_KEY_SIZE_IN_BITS

Key size in bits unsupported.

CSSM_CSP_INVALID_PADDING

Unknown padding.

CSSM_CSP_INVALID_MODE

Unknown algorithm mode for symmetric context.

CSSM_CSP_INVALID_ATTR_PASSPHRASE

Invalid or missing passphrase attribute in the asymmetric context.

CSSM_CSP_PRIKEY_NOT_FOUND

Cannot find the corresponding private key for asymmetric context.

CSSM_CSP_PASSPHRASE_INVALID

Passphrase length error or passphrase badly formed for asymmetric context.

CSSM_CSP_PASSPHRASE_INCORRECT

Passphrase incorrect for asymmetric context.

CSSM_CSP_PRIKEY_ERROR

Error in getting the raw private key or private key storage error for asymmetric context.

CSSM_CSP_INVALID_ATTR_INIT_VECTOR

Init vector attribute data or length error for symmetric context.

Comments

The output is returned to the caller either by filling the caller-specified buffer or by using the application's declared memory allocation functions to allocate buffer space. To specify a specific, pre-allocated output buffer, the caller must provide an array of one or more CSSM_DATA structures each one containing a Length field value greater than zero and a non-NULL Data pointer field value. To specify automatic output buffer allocation by the CSP, the caller must provide an array of one or more CSSM_DATA structures each containing a Length field value equal to zero and a NULL Data pointer field value. The application is always responsible for de-allocating the memory when it is no longer needed. If the CSSM_DATA_PTR parameter is NULL (that is, does not point to an array of CSSM_DATA structures) or the number of CSSM_DATA structures is specified as zero, the error code CSSM_CSP_INVALID_DATA_POINTER is returned. In-place decryption can be done by supplying the same input and output buffers

SEE ALSO

CSSM_QuerySize, CSSM_EncryptData,
CSSM_DecryptDataInit, CSSM_DecryptDataUpdate,
CSSM_DecryptDataFinal