PBE_Scrypt

CryptoSys PKI Pro Manual

PBE_Scrypt

Derives a key of any length from a password using the SCRYPT algorithm.

VBA/VB6 Syntax


Public Declare Function PBE_Scrypt Lib "diCrPKI.dll" (ByRef lpDerivedKey As Byte, ByVal nKeyLen As Long, ByRef lpPwd As Byte, ByVal nPwdLen As Long, ByRef lpSalt As Byte, ByVal nSaltLen As Long, ByVal nParamN As Long, ByVal nParamR As Long, ByVal nParamP As Long, ByVal nOptions As Long) As Long

nRet = PBE_Scrypt(abDerivedKey(0), nKeyLen, abPwd(0), nPwdLen, abSalt(0), nSaltLen, nParamN, nParamR, nParamP, nOptions) ' Note the "(0)" after the byte array parameters

C/C++ Syntax


long __stdcall PBE_Scrypt(unsigned char *lpDerivedKey, long nKeyLen, const unsigned char *lpPwd, long nPwdLen, const unsigned char *lpSalt, long nSaltLen, long nParamN, long nParamR, long nParamP, long nOptions);

Parameters

lpDerivedKey: [out] Byte array to be filled with derived key.
nKeyLen: [in] size of required key in bytes.
lpPwd: [in] Byte array containing the password.
nPwdLen: [in] length of the password in bytes.
lpSalt: [in] Byte array containing the salt.
nSaltLen: [in] length of the salt in bytes.
nParamN: [in] CPU/Memory cost parameter N ("costParameter") a number greater than one and a power of 2.
nParamR: [in] Block size r ("blockSize")
nParamP: [in] Parallelization parameter p ("parallelizationParameter")
nOptions: [in] Option flags: not used in this release. Specify zero.

Returns (VBA/C)

If successful, the return value is 0; otherwise it returns a non-zero error code.

VBA Wrapper Syntax

Public Function pbeScrypt (dkBytes As Long, lpPwd() As Byte, lpSalt() As Byte, nParamN As Long, nParamR As Long, nParamP As Long, Optional nOptions As Long = 0) As Byte()

.NET Equivalent

Pbe.Scrypt Method (Int32, Byte[], Byte[], Int32, Int32, Int32)

C++ (STL) Equivalent

static bvec_t dipki::Pbe::Scrypt (int dklen, const std::string password, const bvec_t &salt, int N, int r, int p)

Python Equivalent

static Pbe.scrypt(dklen, pwdbytes, salt, N, r, p)

Remarks

This uses the SCRYPT algorithm from [RFC7914]. There are restrictions on the values of the parameters N, r and p. In particular, N must be larger than 1 and a power of 2. The output buffer for the derived key abDerivedKey must have been dimensioned to at least the required length nKeyLen in bytes.

Example (VBA core function)

Two examples from [RFC7914].

Dim abPwd() As Byte
Dim abSalt() As Byte
Dim abDK() As Byte
Dim nKeyLen As Long
Dim nPwdlen As Long
Dim nSaltLen As Long
Dim nRet As Long

nKeyLen = 64
' Dimension key byte array
ReDim abDK(nKeyLen - 1)
' Convert strings to byte array form
abPwd = StrConv("password", vbFromUnicode)
abSalt = StrConv("NaCl", vbFromUnicode)
' Get lengths in bytes
nPwdlen = UBound(abPwd) + 1
nSaltLen = UBound(abSalt) + 1
' Call the SCRYPT function to derive a 64-byte key with parameters N=1024, r=8, p=16
nRet = PBE_Scrypt(abDK(0), nKeyLen, abPwd(0), nPwdlen, abSalt(0), nSaltLen, 1024, 8, 16, 0)
Debug.Print "PBE_Scrypt() returns " & nRet & " (expecting 0)"
Debug.Print "KEY=" & cnvHexStrFromBytes(abDK)

PBE_Scrypt() returns 0 (expecting 0)
KEY=FDBABE1C9D3472007856E7190D01E9FE7C6AD7CBC8237830E77376634B373162
2EAF30D92E22A3886FF109279D9830DAC727AFB94A83EE6D8360CBDFA2CC0640

In this second example, we need to pass zero-length byte arrays (representing the empty string) for the password and salt.

' INPUT: (N=16, r=1, p=1)
' P="", S="" => empty strings => byte arrays of length zero
' VBA ISSUE: we cannot pass an empty byte array in the usual way `abPwd(0)`
' because it gives a "Subscript out of range" error.
' FIX: pass `0` for the array parameters and zero for the lengths
nRet = PBE_Scrypt(abDK(0), nKeyLen, 0, 0, 0, 0, 16, 1, 1, 0)
Debug.Print "PBE_Scrypt() returns " & nRet & " (expecting 0)"
Debug.Print "KEY=" & cnvHexStrFromBytes(abDK)

PBE_Scrypt() returns 0 (expecting 0)
KEY=77D6576238657B203B19CA42C18A0497F16B4844E3074AE8DFDFFA3FEDE21442
FCD0069DED0948F8326A753A0FC81F17E8D3E0FB2E0D3628CF35E20C38D18906

Example (VBA wrapper function)

Dim lpPwd() As Byte
Dim lpSalt() As Byte
Dim lpDK() As Byte
lpPwd = StrConv("password", vbFromUnicode)
lpSalt = StrConv("NaCl", vbFromUnicode)
lpDK = pbeScrypt(64, lpPwd, lpSalt, 1024, 8, 16, 0)
Debug.Print "DK=" & cnvHexStrFromBytes(lpDK)
Debug.Print "OK=FDBABE1C9D3472007856E7190D01E9FE7C6AD7CBC8237830E77376634B3731622EAF30D92E22A3886FF109279D9830DAC727AFB94A83EE6D8360CBDFA2CC0640"
' INPUT: (N=16, r=1, p=1)
' P="", S="" => empty strings => byte arrays of length zero
' IMPORTANT: dummy variables *must* be independent
Dim lpDummy1() As Byte
Dim lpDummy2() As Byte
lpDK = pbeScrypt(64, lpDummy1, lpDummy2, 16, 1, 1, 0)
Debug.Print "DK=" & cnvHexStrFromBytes(lpDK)
Debug.Print "OK=77D6576238657B203B19CA42C18A0497F16B4844E3074AE8DFDFFA3FEDE21442FCD0069DED0948F8326A753A0FC81F17E8D3E0FB2E0D3628CF35E20C38D18906"

Dim strDerivedKey As String
strDerivedKey = pbeScryptHex(64, "pleaseletmein", cnvHexStrFromString("SodiumChloride"), 16384, 8, 1, 0)
Debug.Print "Derived key = " & strDerivedKey
Debug.Print "OK =          " & "7023BDCB3AFD7348461C06CD81FD38EBFDA8FBBA904F8E3EA9B543F6545DA1F2D5432955613F0FCF62D49705242A9AF9E61E85DC0D651E40DFCF017B45575887"

PBE_Scrypt

VBA/VB6 Syntax

C/C++ Syntax

Parameters

Returns (VBA/C)

VBA Wrapper Syntax

.NET Equivalent

C++ (STL) Equivalent

Python Equivalent

Remarks

Example (VBA core function)

Example (VBA wrapper function)

See Also