VeraCrypt is a free disk encryption software brought to you by IDRIX (https://www.idrix.fr) and that is based on TrueCrypt. It adds enhanced security to the algorithms used for system and partition encryption, making it immune to new developments in brute-force attacks. It also solves many vulnerabilities and security issues found in TrueCrypt.
As an example, when the system partition is encrypted, TrueCrypt uses PBKDF2-RIPEMD160 with 1000 iterations whereas in VeraCrypt we use 327,661. And for standard containers and other partitions, TrueCrypt uses at most 2000 iterations, but VeraCrypt uses 655,331 for RIPEMD160 and 500,000 iterations for SHA-2 and Whirlpool.
This enhanced security adds some delay only to the opening of encrypted partitions without any performance impact to the application use phase. This is acceptable to the legitimate owner but it makes it much harder for an attacker to gain access to the encrypted data.