Security Scol plugin
|
Hardware generated random numbers using VIA XSTORE. More...
#include <padlkrng.h>
Public Member Functions | |
CRYPTOPP_STATIC_CONSTEXPR const char * | StaticAlgorithmName () |
PadlockRNG (word32 divisor=1) | |
Construct a PadlockRNG generator. | |
virtual void | GenerateBlock (byte *output, size_t size) |
Generate random array of bytes. | |
virtual void | DiscardBytes (size_t n) |
Generate and discard n bytes. | |
virtual void | IncorporateEntropy (const byte *input, size_t length) |
Update RNG state with additional unpredictable values. | |
std::string | AlgorithmProvider () const |
Retrieve the provider of this algorithm. | |
word32 | SetDivisor (word32 divisor) |
Set the XSTORE divisor. | |
word32 | GetDivisor () const |
Get the XSTORE divisor. | |
word32 | GetMSR () const |
Get the MSR for the last operation. | |
Public Member Functions inherited from RandomNumberGenerator | |
virtual bool | CanIncorporateEntropy () const |
Determines if a generator can accept additional entropy. | |
virtual byte | GenerateByte () |
Generate new random byte and return it. | |
virtual unsigned int | GenerateBit () |
Generate new random bit and return it. | |
virtual word32 | GenerateWord32 (word32 min=0, word32 max=0xffffffffUL) |
Generate a random 32 bit word in the range min to max, inclusive. | |
virtual void | GenerateIntoBufferedTransformation (BufferedTransformation &target, const std::string &channel, lword length) |
Generate random bytes into a BufferedTransformation. | |
template<class IT > | |
void | Shuffle (IT begin, IT end) |
Randomly shuffle the specified array. | |
Public Member Functions inherited from Algorithm | |
Algorithm (bool checkSelfTestStatus=true) | |
Interface for all crypto algorithms. | |
virtual std::string | AlgorithmName () const |
Provides the name of this algorithm. | |
Public Member Functions inherited from Clonable | |
virtual Clonable * | Clone () const |
Copies this object. | |
Protected Member Functions | |
word32 | DivisorHelper (word32 divisor) |
Hardware generated random numbers using VIA XSTORE.
Some VIA processors provide a Security Engine called Padlock. The Padlock Security Engine provides AES, SHA and a RNG. The PadlockRNG class provides access to the RNG.
The VIA generator uses an 8 byte FIFO buffer for random numbers. The generator can be configured to discard bits from the buffer to resist analysis. The divisor
controls the number of bytes discarded. The formula for the discard amount is 2**divisor - 1
. When divisor=0
no bits are discarded and the entire 8 byte buffer is read. If divisor=3
then 7 bytes are discarded and 1 byte is read. TheVIA SDK samples use divisor=1
.
Cryptography Research, Inc (CRI) audited the Padlock Security Engine in 2003. CRI provided recommendations to operate the generator for secure and non-secure applications. Additionally, the Programmers Guide and SDK provided a different configuration in the sample code.
You can operate the generator according to CRI recommendations by setting divisor
, reading one word (or partial word) at a time from the FIFO, and then inspecting the MSR after each read.
The audit report with recommendations is available on the Crypto++ wiki at VIA Padlock.
Definition at line 50 of file padlkrng.h.
|
inlinevirtual |
Definition at line 55 of file padlkrng.h.
PadlockRNG::PadlockRNG | ( | word32 | divisor = 1 | ) |
Construct a PadlockRNG generator.
divisor | the XSTORE divisor |
Some VIA processors provide a Security Engine called Padlock. The Padlock Security Engine provides AES, SHA and a RNG. The PadlockRNG class provides access to the RNG.
The VIA generator uses an 8 byte FIFO buffer for random numbers. The generator can be configured to discard bits from the buffer to resist analysis. The divisor
controls the number of bytes discarded. The formula for the discard amount is 2**divisor - 1
. When divisor=0
no bits are discarded and the entire 8 byte buffer is read. If divisor=3
then 7 bytes are discarded and 1 byte is read. VIA SDK samples use divisor=1
.
Cryptography Research, Inc (CRI) audited the Padlock Security Engine in 2003. CRI provided recommendations to operate the generator for secure and non-secure applications. Additionally, the Programmers SDK provided a different configuration in the sample code.
The audit report with recommendations is available on the Crypto++ wiki at VIA Padlock.
Definition at line 25 of file padlkrng.cpp.
|
virtual |
Retrieve the provider of this algorithm.
The algorithm provider can be a name like "C++", "SSE", "NEON", "AESNI", "ARMv8" and "Power8". C++ is standard C++ code. Other labels, like SSE, usually indicate a specialized implementation using instructions from a higher instruction set architecture (ISA). Future labels may include external hardware like a hardware security module (HSM).
Generally speaking Wei Dai's original IA-32 ASM code falls under "SSE2". Labels like "SSSE3" and "SSE4.1" follow after Wei's code and use intrinsics instead of ASM.
Algorithms which combine different instructions or ISAs provide the dominant one. For example on x86 AES/GCM
returns "AESNI" rather than "CLMUL" or "AES+SSE4.1" or "AES+CLMUL" or "AES+SSE4.1+CLMUL".
Reimplemented from Algorithm.
Definition at line 20 of file padlkrng.cpp.
|
virtual |
Generate and discard n bytes.
n | the number of bytes to generate and discard |
the Padlock generator discards words, not bytes. If n is not a multiple of a 32-bit word, then it is rounded up to that size.
Reimplemented from RandomNumberGenerator.
Definition at line 91 of file padlkrng.cpp.
Definition at line 126 of file padlkrng.h.
|
virtual |
Generate random array of bytes.
output | the byte buffer |
size | the length of the buffer, in bytes |
Reimplemented from RandomNumberGenerator.
Definition at line 34 of file padlkrng.cpp.
|
inline |
Get the XSTORE divisor.
Definition at line 113 of file padlkrng.h.
|
inline |
Get the MSR for the last operation.
Definition at line 120 of file padlkrng.h.
|
inlinevirtual |
Update RNG state with additional unpredictable values.
input | unused |
length | unused |
The operation is a nop for this generator.
Reimplemented from RandomNumberGenerator.
Definition at line 93 of file padlkrng.h.
Set the XSTORE divisor.
divisor | the XSTORE divisor |
Definition at line 104 of file padlkrng.h.
|
inline |
Definition at line 53 of file padlkrng.h.