The abbreviation SHA stands for Secure Hash Algorithm. The secure hash algorithm refers to a group of standardized hash functions.
SHA1 was a very important cryptographic hash function in the 1990s. It has been considered insecure since 2004.
SHA2 differs from SHA1 in several features and functions. SHA2 includes SHA-224, SHA-256, SHA-384 and SHA-512. The number after the hyphen indicates the length of the hash value in bits.