Encryption key strengths

Encryption systems are often grouped into families of symmetric (single key) and asymmetric systems (a key to encrypt and another to decrypt). They also can be grouped according to the central algorithm used, such as elliptic curve cryptography. Here are some standard key sizes and the level of protection they provide.

Symmetric
Asymmetric
Elliptic Curve
Applications
80-bit*
1,024-bit RSA
160-bit
Ephemeral data, i.e. stock trades
112-bit
 2,048-bit RSA*
 224-bit
E-commerce, Internet banking
128-bit
 3,072-bit RSA*
256-bit
 Classified to secret level
192, 256-bit
15,360-bit RSA
512-bit
Highly sensitive, top secret

*80-bit keys are valid until 2010, according to the National Institute of Standards and Technology
*2,048-bit sufficient until 2030, according to RSA
*3,072-bit sufficient beyond 2030, according to RSA

Source: National Institute of Standards and Technology, RSA

About the Author

Rutrell Yasin is is a freelance technology writer for GCN.

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