The SHA-2 family of cryptographic hash functions consists of six hash functions. These are:
- SHA-224, with 224 bit hash values
- SHA-256, with 256 bit hash values
- SHA-384, with 384 bit hash values
- SHA-512, with 512 bit hash values
- SHA-512/224, with 512 bit hash values
- SHA-512/256, with 512 bit hash values
Among these, SHA-256 and SHA-512 are the most commonly accepted and used hash functions computed with 32-bit and 64-bit words, respectively. SHA-224 and SHA-384 are truncated versions of SHA-256 and SHA-512 respectively, computed with different initial values.
To calculate cryptographic hashing value in Java, MessageDigest Class is used, under the package java.security.
MessagDigest Class provides following cryptographic hash function to find hash value of a text as follows:
These algorithms are initialized in static method called getInstance(). After selecting the algorithm the message digest value is calculated and the results is returned as byte array. BigInteger class is used, to convert the resultant byte array into its signum representation. This representation is then converted into hexadecimal format to get the expected MessageDigest.
Input : hello world
Output : 309ecc489c12d6eb4cc40f50c902f2b4d0ed77ee511a7c7a9bcd3ca86d4cd86f989dd35bc5ff499670da34255b45b0cfd830e81f605dcf7dc5542e93ae9cd76f
Input : GeeksForGeeks
Output : acc10c4e0b38617f59e88e49215e2e894afaee5ec948c2af6f44039f03c9fe47a9210e01d5cd926c142bdc9179c2ad30f927a8faf69421ff60a5eaddcf8cb9c
Program: Below program shows the implementation of SHA-512 hash function:
HashCode Generated by SHA-512 for: GeeksForGeeks : acc10c4e0b38617f59e88e49215e2e894afaee5 ec948c2af6f44039f03c9fe47a9210e01d5cd926c142bdc9179c2ad 30f927a8faf69421ff60a5eaddcf8cb9c hello world : 309ecc489c12d6eb4cc40f50c902f2b4d0ed77ee5 11a7c7a9bcd3ca86d4cd86f989dd35bc5ff499670da34255b45b0cf d830e81f605dcf7dc5542e93ae9cd76f
- Data Integrity
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