There are a lot of Delphi programming sites. These are some of my favorites.
David Barton has a good encryption library Dcpcrypt . David's version does not work directly with Delphi XE3. There are a few changes that need to be made to the source code. Ask me for my updated version if you don't want to track down the changes yourself. It will work in 32 and 64 bit Delphi. Another popular encryption library is Delphi Encryption Compendium .
Right now DEC is 32 bit only. I have modified it to work with 64 bit Delphi. It is not a complete conversion. There is a lot of 32 bit assembly that does not work on 64 bit. I have most functions working except "haval" for instance. I have removed most of the assembly language using pure Pascal and converted a few assembly routines that were easy to translate to 64 bit. I am using my modified version in kb Text Converter (see Software). Contact me for more information.
Wolfgang Ehrhardt has a lot of math, encryption and random number routines. He has done a great job making compatible libraries that work with Delphi XE3 all the way back to Turbo Pascal 6.
I also have a random number library that includes:
AES in Counter Mode, Complementary Multiply with Carry 4096, ISAAC, ISAAC64, Kiss123, 6 Linear Congruential (1 64-bit), Mersenne Twister, Mersenne Twister64, Multiply with Carry, Multiply with Carry 256, RKiss, Rkiss64, Taus113 (ps), Taus88 (ps), TT800, WELL1024, WELL512, WELL19337, WELL44497, Xor4096, XorShift, HC-128, HC-256 and the Windows cryptographically secure - CryptGenRandom. ISAAC and HC-256 are also cryptographically secure.These routines are free for educational and "not for profit" uses. Most are free for commercial uses too - but some are not - you need to check with the original authors (WELL for instance). I believe that all are free for commercial use except for WELL. All I did was type them in, convert them from C and develop the class structure and then test them :)
Thanks to Bob Jenkins, François Panneton, Pierre L'Écuyer, George Marsaglia, Joan Daemen and Vincent Rijmen, Makoto Matsumoto, Takuji Nishimura, Yoshiharu Kurita, Hongjun Wu and Richard Brent for developing the mathematics behind these RNG's and making the math public.
In my Random Library, the RNG's are implemented as classes and all share the same interface so it is easy to substitute one for another. You can have multiple instances of one generator or use them all in one program. AES in counter mode is in a separate unit because it is large and complex but can be used with the others. All the classes are seeded with random numbers from CryptgenRandom (dev/random when not in Windows) when they are created. You can seed them with your own values when you are doing modeling and need to generate the same sequence. The base class includes functions to return 64, 32, 8 bit values and ranges with and without the MOD function. All the bytes get used not just the least significant ones. There are functions to return a real value between [0..1) and (-1..1). I have checked them all with Die Hard and they are all functioning properly. There is an experimental mode to make long period generators cryptographically secure according to a method in Cryptographic Mersenne Twister (pdf). The Linear Congruential generators all fail half of the Die Hard tests but that is normal for those generators. The library will work with Delphi 6 up to Delphi XE3. It should also work with Free Pascal. Contact me for more information.
Which is the best psuedo-random number generator? I don't know. They all generate very good numbers that pass the Diehard tests - except Linear Congruential. ISAAC and AES in counter mode are cryptographically secure. There are a few that are very fast. Speed doesn't seem to be an issue these days. I used to use Mersenne Twister but now I use ISAAC for my game programs. If you use Mersenne Twister, you should consider switching to WELL. Well is faster and has better equidistribution properties - See Link.
I use Delphi from Embarcadero . There are also free programming systems Free Pascal and Lazarus . Lazarus is the development environment that uses the Free Pascal compiler.
A good site with Delphi examples is Delphi About.com .
Need help with your Delphi project? I'm available for consulting and contract programming. I've been programming Pascal since Turbo Pascal 3 (1985), and Delphi since Delphi 1 (1995). I am currently using Delphi XE 3 (2012). I have experience in many other programming aspects as well. See my Contact page.