ISSUE-27: Specification of AES-CTR mode counter bits
aes ctr
Specification of AES-CTR mode counter bits
- State:
- CLOSED
- Product:
- crypto for Web Crypto API
- Raised by:
- Ryan Sleevi
- Opened on:
- 2012-08-22
- Description:
- Under the AesCtrParams [1], callers can currently specify an initial value for the counter, as well as a length for how many bits are used for the block counter. Such a specification matches the PKCS#11 definition for AES-CTR, although other APIs such as CDSA, CryptoAPI, and CNG, do not support explicit counter mode, and instead only support ECB as a foundation for CTR.
However, by only specifying the length in bits of the counter, it presumes that the counter bits are either in the most-significant or least-significant bytes. Different systems using AES-CTR may place the block counter in different places - some using the MSB, others using the LSB. Thus, should the API specify an 'offset' as well that, when combined with length, gives a clear position of where the block counter is (internally managed by the API), and where the message counter/nonce are (externally managed by the caller)
[1] http://www.w3.org/2012/webcrypto/WebCryptoAPI/#dfn-AesCtrParams - Related Actions Items:
ACTION-56 on Wan-Teh Chang to Write proposal for ISSUE-27 - due 2012-10-15, closed- Related emails:
- Re: crypto-ISSUE-27 (aes ctr): Specification of AES-CTR mode counter bits [Web Cryptography API] (from wtc@google.com on 2012-10-25)
- W3C Web Crypto WG - agenda for 22nd of october call - today (from Virginie.GALINDO@gemalto.com on 2012-10-22)
- [minutes] 15 October WebCrypto Call (from wseltzer@w3.org on 2012-10-17)
- Re: crypto-ISSUE-27 (aes ctr): Specification of AES-CTR mode counter bits [Web Cryptography API] (from wtc@google.com on 2012-10-16)
- W3C Web Crypto WG - Take Away from 16th of Oct call (from Virginie.GALINDO@gemalto.com on 2012-10-16)
- RE: W3C Web Crypto WG - agenda for 15th of october call - today (from Vijay.Bharadwaj@microsoft.com on 2012-10-15)
- RE: W3C Web Crypto WG - agenda for 15th of october call - today (from Asad.Ali@gemalto.com on 2012-10-15)
- Re: W3C Web Crypto WG - agenda for 15th of october call - today (from rbarnes@bbn.com on 2012-10-15)
- Re: crypto-ISSUE-27 (aes ctr): Specification of AES-CTR mode counter bits [Web Cryptography API] (from sleevi@google.com on 2012-10-15)
- Re: W3C Web Crypto WG - agenda for 15th of october call - today (from S.Durbha@cablelabs.com on 2012-10-15)
- Re: W3C Web Crypto WG - agenda for 15th of october call - today (from wtc@google.com on 2012-10-15)
- Re: crypto-ISSUE-27 (aes ctr): Specification of AES-CTR mode counter bits [Web Cryptography API] (from wtc@google.com on 2012-10-15)
- Re: W3C Web Crypto WG - agenda for 15th of october call - today (from mountie.lee@mw2.or.kr on 2012-10-15)
- W3C Web Crypto WG - agenda for 15th of october call - today (from Virginie.GALINDO@gemalto.com on 2012-10-15)
- W3C Web Crypto - classifying issues - a new proposal (from Virginie.GALINDO@gemalto.com on 2012-09-22)
- Re: W3C Web Crypto - classifying issues - a new proposal (from sleevi@google.com on 2012-09-21)
- RE: W3C Web Crypto - classifying issues - a new proposal (from Virginie.GALINDO@gemalto.com on 2012-09-21)
- W3C Web Crypto WG - Support for ECB (from Virginie.GALINDO@gemalto.com on 2012-09-10)
- RE: crypto-ISSUE-27 (aes ctr): Specification of AES-CTR mode counter bits [Web Cryptography API] (from Vijay.Bharadwaj@microsoft.com on 2012-09-04)
- Re: crypto-ISSUE-27 (aes ctr): Specification of AES-CTR mode counter bits [Web Cryptography API] (from wtc@google.com on 2012-08-31)
- RE: crypto-ISSUE-27 (aes ctr): Specification of AES-CTR mode counter bits [Web Cryptography API] (from Vijay.Bharadwaj@microsoft.com on 2012-08-28)
- Re: crypto-ISSUE-27 (aes ctr): Specification of AES-CTR mode counter bits [Web Cryptography API] (from wtc@google.com on 2012-08-27)
- Re: crypto-ISSUE-27 (aes ctr): Specification of AES-CTR mode counter bits [Web Cryptography API] (from sleevi@google.com on 2012-08-27)
- RE: crypto-ISSUE-27 (aes ctr): Specification of AES-CTR mode counter bits [Web Cryptography API] (from Vijay.Bharadwaj@microsoft.com on 2012-08-27)
- crypto-ISSUE-27 (aes ctr): Specification of AES-CTR mode counter bits [Web Cryptography API] (from sysbot+tracker@w3.org on 2012-08-22)
Related notes:
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