Red Pike (cipher) - Misplaced Pages

(Redirected from Thames Bridge (cryptography)) Block cipher

Red Pike is a classified United Kingdom government encryption algorithm, proposed for use by the National Health Service by GCHQ, but designed for a "broad range of applications in the British government" Archived 2004-04-23 at the Wayback Machine. Little is publicly known about Red Pike, except that it is a block cipher with a 64-bit block size and 64-bit key length. According to the academic study of the cipher cited below and quoted in a paper by Ross Anderson and Markus Kuhn, it "uses the same basic operations as RC5" (add, XOR, and left shift) and "has no look-up tables, virtually no key schedule and requires only five lines of code"; "the influence of each key bit quickly cascades" and "each encryption involves of the order of 100 operations". 64 bits of key entropy are not considered secure anymore.

Red Pike is available to approved British government contractors in software form, for use in confidential (not secret) government communication systems. GCHQ also designed the Rambutan cryptosystem for the same segment.

Given that Red Pike is a British encryption algorithm, its name likely refers to a particular fell in the western English Lake District.

Supposed source code

In February 2014, the supposed source code for Red Pike was posted as follows to the Cypherpunk mailing list.

 /* Red Pike cipher source code */
 #include <stdint.h>
 typedef uint32_t word;
 #define CONST 0x9E3779B9
 #define ROUNDS 16
 #define ROTL(X, R) (((X) << ((R) & 31)) | ((X) >> (32 - ((R) & 31))))
 #define ROTR(X, R) (((X) >> ((R) & 31)) | ((X) << (32 - ((R) & 31))))
 void encrypt(word * x, const word * k)
 {
   unsigned int i;
   word rk0 = k;
   word rk1 = k;
   for (i = 0; i < ROUNDS; i++)
   {
     rk0 += CONST;
     rk1 -= CONST;
     x ^= rk0;
     x += x;
     x = ROTL(x, x);
     x = ROTR(x, x);
     x -= x;
     x ^= rk1;
   }
   rk0 = x; x = x; x = rk0;
 }
 void decrypt(word * x, const word * k)
 {
   word dk =
   {
     k - CONST * (ROUNDS + 1),
     k + CONST * (ROUNDS + 1)
   };
   encrypt(x, dk);
 }

References

"Red Pike cipher", Red Pike cipher, Cypherpunk mailing list, Gmane

C Mitchell, S Murphy, F Piper, P Wild. (1996). Red Pike — an assessment. Codes and Ciphers Ltd 2/10/96.
Paper by Anderson and Kuhn which includes excerpts from (Mitchell et al., 1996). Another version is Anderson, Ross; Kuhn, Markus (1997). "Low Cost Attacks on Tamper Resistant Devices" (PDF). Security Protocols, 5th International Workshop. pp. 125–136.
"The use of encryption and related services with the NHSnet"

v t e Block ciphers (security summary)
Common algorithms	AES Blowfish DES (internal mechanics, Triple DES) Serpent SM4 Twofish
Less common algorithms	ARIA Camellia CAST-128 GOST IDEA LEA RC5 RC6 SEED Skipjack TEA XTEA
Other algorithms	3-Way Adiantum Akelarre Anubis Ascon BaseKing BassOmatic BATON BEAR and LION CAST-256 Chiasmus CIKS-1 CIPHERUNICORN-A CIPHERUNICORN-E CLEFIA CMEA Cobra COCONUT98 Crab Cryptomeria/C2 CRYPTON CS-Cipher DEAL DES-X DFC E2 FEAL FEA-M FROG G-DES Grand Cru Hasty Pudding cipher Hierocrypt ICE IDEA NXT Intel Cascade Cipher Iraqi Kalyna KASUMI KeeLoq KHAZAD Khufu and Khafre KN-Cipher Kuznyechik Ladder-DES LOKI (97, 89/91) Lucifer M6 M8 MacGuffin Madryga MAGENTA MARS Mercy MESH MISTY1 MMB MULTI2 MultiSwap New Data Seal NewDES Nimbus NOEKEON NUSH PRESENT Prince Q RC2 REDOC Red Pike S-1 SAFER SAVILLE SC2000 SHACAL SHARK Simon Speck Spectr-H64 Square SXAL/MBAL Threefish Treyfer UES xmx XXTEA Zodiac
Design	Feistel network Key schedule Lai–Massey scheme Product cipher S-box P-box SPN Confusion and diffusion Round Avalanche effect Block size Key size Key whitening (Whitening transformation)
Attack (cryptanalysis)	Brute-force (EFF DES cracker) MITM Biclique attack 3-subset MITM attack Linear (Piling-up lemma) Differential Impossible Truncated Higher-order Differential-linear Distinguishing (Known-key) Integral/Square Boomerang Mod n Related-key Slide Rotational Side-channel Timing Power-monitoring Electromagnetic Acoustic Differential-fault XSL Interpolation Partitioning Rubber-hose Black-bag Davies Rebound Weak key Tau Chi-square Time/memory/data tradeoff
Standardization	AES process CRYPTREC NESSIE NSA Suite B CNSA
Utilization	Initialization vector Mode of operation Padding

v t e Cryptography
General	History of cryptography Outline of cryptography Classical cipher Cryptographic protocol Authentication protocol Cryptographic primitive Cryptanalysis Cryptocurrency Cryptosystem Cryptographic nonce Cryptovirology Hash function Cryptographic hash function Key derivation function Secure Hash Algorithms Digital signature Kleptography Key (cryptography) Key exchange Key generator Key schedule Key stretching Keygen Machines Cryptojacking malware Ransomware Random number generation Cryptographically secure pseudorandom number generator (CSPRNG) Pseudorandom noise (PRN) Secure channel Insecure channel Subliminal channel Encryption Decryption End-to-end encryption Harvest now, decrypt later Information-theoretic security Plaintext Codetext Ciphertext Shared secret Trapdoor function Trusted timestamping Key-based routing Onion routing Garlic routing Kademlia Mix network
Mathematics	Cryptographic hash function Block cipher Stream cipher Symmetric-key algorithm Authenticated encryption Public-key cryptography Quantum key distribution Quantum cryptography Post-quantum cryptography Message authentication code Random numbers Steganography
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Supposed source code

See also

References