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SHA-256 cryptography software

SHA-256 produces a 256-bit (32-byte) message digest hash and is meant to provide 128 bits of security against collision attacks.

SHA-256 is specified in FIPS PUB 180 Secure Hash Standard, (pdf-link).

The hash functions SHA-256, SHA-384, SHA-512 and SHA-224 are now collectively referred to as SHA-2 hash functions, not to be confused with the SHA2_ functions in CryptoSys API, which we released long before the the term was in general use.

The original SHA-256 functions available in CryptoSys API

VB6/C Functions	.NET methods
`SHA2_StringHexHash` `SHA2_BytesHexHash` `SHA2_FileHexHash` `SHA2_Init` `SHA2_AddBytes` `SHA2_AddString` `SHA2_HexDigest` `SHA2_Reset` `SHA2_Hmac`	`Sha256.HexHash Method (String)` `Sha256.HexHash Method (Byte[])` `Sha256.FileHexHash Method` `Sha256.Init Method` `Sha256.AddData Method (Byte[])` `Sha256.AddData Method (String)` `Sha256.HexDigest Method` `Sha256.Reset Method` `Sha256.Hmac Method`

The SHA_2Hmac function provides HMAC, a mechanism for message authentication using the SHA-256 cryptographic hash function. For more details, refer to the original specification RFC 2104 HMAC: Keyed-Hashing for Message Authentication, Krawczyk, Bellare and Canetti, February 1997, and FIPS PUB 198 The Keyed-Hash Message Authentication Code (HMAC), March 2002.

Newer SHA-1 and SHA-2 functions available in CryptoSys API

These generic hash functions provide SHA-1, SHA-224, SHA-256, SHA-384 and SHA-512.

VB6/C Functions	.NET methods
`HASH_Bytes` `HASH_File` `HASH_HexFromBytes` `HASH_HexFromFile` `HASH_HexFromHex`	`Hash.BytesFromBytes Method` `Hash.BytesFromFile Method` `Hash.HexFromBytes Method` `Hash.HexFromFile Method` `Hash.HexFromHex Method`

And these generic MAC functions provide the HMAC function with all variants of SHA.

VB6/C Functions	.NET methods
`MAC_Bytes` `MAC_HexFromBytes` `MAC_HexFromHex`	`Mac.BytesFromBytes Method` `Mac.HexFromBytes Method` `Mac.HexFromHex Method`

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This page last updated 15 August 2025.