Developer Reference

Contents

TDESDecryptCTR

Decrypts a variable length data stream in the CTR mode (deprecated).

Syntax

IppStatus ippsTDESDecryptCTR(const Ipp8u *
pSrc
, Ipp8u *
pDst
, int
дen
,
const IppsDESSpec *
pCtx1
, const IppsDESSpec *
pCtx2,
const IppsDESSpec *
pCtx3,
Ipp8u *
pCtrValue
, int
ctrNumBitSize
);
Include Files
ippcp.h
Parameters
pSrc
Input ciphertext data stream of a variable length.
pDst
Resulting plaintext data stream.
дen
Length of the plaintext data stream in bytes.
pCtx1
First set of round keys scheduled for TDES internal operations.
pCtx2
Second set of round keys scheduled for TDES internal operations.
pCtx3
Third set of round keys scheduled for TDES internal operations.
pCtrValue
Counter.
ctrNumBitSize
Number of bits in the specific part of the counter to be incremented.
Description
This algorithm is considered weak due to known attacks on it. The functionality remains in the library, but the implementation will no longer be optimized and no security patches will be applied. A more secure alternative is available: AES.
This function decrypts the input data stream of a variable length according to the cipher scheme specified in the [NIST SP 800-38A] recommendation. The function uses three sets of the supplied round keys. The standard incrementing function is applied to increment value of counter. The function returns the ciphertext result.
Return Values
ippStsNoErr
Indicates no error. Any other value indicates an error or warning.
ippStsNullPtrErr
Indicates an error condition if any of the specified pointers is
NULL
.
ippStsLengthErr
Indicates an error condition if the descrypted plaintext data stream length is less that or equal to zero.
ippStsCTRSizeErr
Indicates an error condition if the value of the
ctrNumBitSize
is illegal.
ippStsContextMatchErr
Indicates an error condition if the context parameter does not match the operation.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.