HASH_Bytes

Creates a message digest hash as a byte array from byte data. The hash algorithm to use is passed in the options parameter.

VB6/VBA Syntax

nRet = HASH_Bytes(abDigest(0), nDigLen, abMessage(0), nMsgLen, nOptions)


Parameters

abDigest

[out] Byte array to receive the hash digest.

nDigLen

[in] Long specifying the length in bytes of the output array.

abMessage

[in] Byte array containing the message data

nMsgLen

[in] Long specifying length of the message data in bytes.

nOptions

[in] Long Option flags. Select one of:
PKI_HASH_SHA1 (0) to use the SHA-1 algorithm (default)
PKI_HASH_MD5 to use the MD5 algorithm
PKI_HASH_MD2 to use the MD2 algorithm
PKI_HASH_SHA256 to use the SHA-256 algorithm
PKI_HASH_SHA384 to use the SHA-384 algorithm
PKI_HASH_SHA512 to use the SHA-512 algorithm
PKI_HASH_SHA224 to use the SHA-224 algorithm

C/C++ Syntax

Returns (VB6/C)

Long: If successful, the return value is the number of bytes in the hash digest array; otherwise it returns a negative error code.

.NET Equivalent

Hash.BytesFromBytes Method

Remarks

Specify a zero nDigLen parameter to find out the required length of the output array. The maximum possible length is PKI_MAX_HASH_BYTES. Hint: SHA-1 requires 20 bytes; MD5 and MD2 require 16 bytes; SHA-512 requires 64. The final digest will be truncated to the specified length if less than the expected size.

VB6/VBA users: Note the '(0)' after the byte array parameters.

Example

    Dim nRet As Long
    Dim abDigest() As Byte
    Dim abMessage() As Byte
    Dim nMsgLen As Long
    ' Set up message to be hashed
    abMessage = StrConv("abc", vbFromUnicode)
    nMsgLen = UBound(abMessage) + 1
    ' Pre-dimension digest array (NB zero-based so subtract one)
    ReDim abDigest(PKI_MAX_HASH_BYTES - 1)
    ' Create default hash (SHA1)
    nRet = HASH_Bytes(abDigest(0), PKI_MAX_HASH_BYTES, abMessage(0), nMsgLen, 0)
    If nRet > 0 Then ReDim Preserve abDigest(nRet - 1)
    Debug.Print nRet, cnvHexStrFromBytes(abDigest)
    
    ' Repeat for MD5
    ReDim abDigest(PKI_MAX_HASH_BYTES - 1)
    nRet = HASH_Bytes(abDigest(0), PKI_MAX_HASH_BYTES, abMessage(0), nMsgLen, PKI_HASH_MD5)
    If nRet > 0 Then ReDim Preserve abDigest(nRet - 1)
    Debug.Print nRet, cnvHexStrFromBytes(abDigest)

The above example should produce the following output:

 20           A9993E364706816ABA3E25717850C26C9CD0D89D
 16           900150983CD24FB0D6963F7D28E17F72

See Also

HASH_HexFromBytes

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