Hash a string:

Digital fingerprint of data:

SHA256 hash given in hexadecimal form:

Hash a general expression:

Equivalently:

Compare all the different hash codes:

512-bit SHA code given as an integer:

512-bit SHA code given as a decimal string, including leading zeroes:

Compare the different string representations of a hash:

The double SHA code given as a ByteArray:

The byte array contains the 256 bits of the result:

View the individual bytes in the array:

When using ByteArray or a string, literal bytes are hashed:

For non-ASCII characters, UTF-8 representation is used for hashing:

Compute a cryptographic hash of zero bytes:

Provide a "checksum" to validate data integrity:

Change some of the data:

The checksum has changed:

A concatenated cryptographic hash function:

Hash code of "abcdef":

The hash is always the same for identical expressions:

Distinct hash codes come from distinct inputs:

The default hash code is "Expression":

The "Expression" hash fits in a machine word:

The leading bit is zero:

"Integer" is the default format:

"DecimalString" is the string version of "Integer", padded with zeros if necessary:

"HexString" is a base 16 representation, padded with zeros if necessary:

"Base36String" is a base 36 representation, padded with zeros if necessary:

"Base64Encoding" encodes bytes of the result using Base64 encoding:

"ByteArray" is a base 256 representation:

Convert from base 256 to an integer:

The result is the same:

Repeated hash can be obtained by using ByteArray as an intermediate result:

FileHash[file,code] is effectively equivalent to Hash[ReadByteArray[file],code]:

Hash of a List of integers uses a serialized version of the list as an expression:

To hash literal bytes, use a ByteArray:

ASCII strings can be used to hash 7-bit byte values:

The Hash of an expression and a string containing the FullForm of the expression are different:

Hash takes into account the full symbol name, including its Context, which may result in different hash values:

Hash collisions are very rare, but possible. Here are two lists of bytes:

They are not the same:

They differ in two locations:

Hash the two sequences of bytes:

Their hashes are identical:

Distribution of hash values for different types: