PACTS (Parallelized Adaptive Cipher with Transposition and Substitution) is a new class of Symmetric Cryptographic Algorithm designed using traditional techniques to efficiently utilize the parallel computing capabilities of the modern computing systems. It overcomes the performance inconsistencies prevalent in conventional cryptographic algorithms when they are implemented in different computing systems with different processing capabilities. The size of the key and the plain text blocks of PACTS are each 1024-bits. The adaptive nature of this algorithm is achieved by incorporating flexibility in the size of the key and plain text sub-blocks and the number of rounds. Level of Intra-packet parallelization, variety in grain size and the required security strength are achieved by suitably deciding the sub-block size. Flow of the algorithm is made dynamic by determining the execution steps at runtime using the value of the key. In spite of these advantages PACTS always produces the same cipher text block for a particular plain text block when the same key is used. CBC mode along with 2-way and 4 way Interleaved CBC modes are employed to overcome this problem. The performance of the PACTS in ECB, CBC and Interleaved CBC modes are analyzed with implementations in shared memory parallel computing environment using OpenMP, Java Threads and MPI.