Chilkat Crypt is an advanced ActiveX encryption component that offers RSA public-key

encryption with digital signatures as well as symmetric encryption algorithms including

AES (Rijndael), Blowfish, and Twofish. In addtion to encryption, you can create
digital
signatures for files or memory data, or verify digital signatures against
incoming
data or files. It allows for the use of any Cryptographic Service Provider,
including
Smart Cards.

Easy and advanced encryption, decryption and hash ActiveX component for ASP or AS
Support encryption and decryption of file, string, memory buffer
Support calculation of hash on string, file or memory buffer
Support digital signature creation and validation
Support state of art crypto algorithm like RC2, RC4, MD2, MD4, MD5, SHA, SHA256, SHA384, SHA512, DES, 3DES, 3DES2, AES128, AES192, AES256
Import and export key in plain or raw bits

This high-performance Zip/Unzip compression ActiveX component has the industry's richest feature set and uses the fastest multi-threaded compression engine available. Its clear design and impeccable documentation will ensure your compression needs are implemented quickly and easily. Supports all languages through ActiveX or DLL interfaces. Now includes WinZip 9.0-compatible AES strong encryption.

High-performance and easy-to-use compression/encryption library. It has the all you need to compress and encrypt files, memory buffers and strings.
-Wide range of compression algorithms and modes
-Extremely fast modes
-Better rate than Rar, Zip, BZip
-Strong encryption - AES Rijndael
-One stream for transparent compression/decompression for write/read
-Forward and backward seeks in stream
-Read and write any portion of data

Use Cryptocx to encrypt your data, totally securing it. EasyByte Cryptocx v5 builds upon the previous releases of Cryptocx to add further powerful features in a very easy to use bundle. The versatility of Cryptocx, combined with the fastest file encryption available anywhere
Full OpenPGP support and the ability to create Self Decrypting Archives SDA, makes Cryptocx an essential component for full data security

Lightweight component that provides strong encryption for your applications. It provides supports for most common crypto algorithms, such as
AES, DES, TripleDES, Blowfish, Cast, RC2, RC4, RC5
for symmetric encryption and decryption,
RSA, DSA, for making and verifying signatures,
and MD5, SHA1 for creating hashes

WeOnlyDo Software's wodHttpDLX is a HTTP client ActiveX control that provides easy, both high and low level access to the complete HTTP protocol. It's primary purpose is to retrieve documents and other resources from the WEB. It was designed to be as programmer-friendly as possible. You will find it can be fully automated to get you requested resource, but also can be used by advanced programmers under complete control from your code.

MailBee SSL component is a plugin which enables MailBee Objects (SMTP, POP3 and IMAP4) to communicate to mail servers over secure connections. Supports client and server certificates, custom stores, STARTTLS mode, and more. Requires just a few lines of code to completely turn existing application into secure one. Royalty-free distribution.

Xceed Encryption Library lets Windows apps encrypt/decrypt data using latest industry standard strong encryption algorithms. Supports traditional secret-key encryption & public-key encryption, and can encrypt/decrypt memory buffers, strings, blobs, streaming data or files. Supports AES (US Advanced Encryption Standard) symmetric encryption algorithm (Rijndael) and Twofish, the runner-up for AES. Also offers RSA algorithm with unlimited key sizes.

With the Open SSL 0.9.7c library, developers can write applications that take advantage of Secure Sockets Layer (SSL v2/v3), Transport Layer Security (TLS v1), and a full-strength general-purpose cryptography library. Security features such as data integrity, authenticity, and privacy can be implemented. To compile for Win32, Perl or compiling under Cygwin is required. Some of the encryption routines/algorithms are covered by patents.

A security toolkit letting even less experienced programmers add encryption and authentication services to their apps, features that are becoming indispensable. The library hides low-level details of security from developers. It supports a variety of algorithms for symmetric/asymmetric encryption, authentication, and hashing. The library is free for non-commercial/shareware projects. It is written in C. ActiveX and C++ wrappers are available.