Encryption code

An encryption code, otherwise known as an encryption key or an encryption scheme, is a functional parameter of cryptological encoding used for security purposes.

Cryptological theory
Encryption only enables senders with the appropriate decryption devices to read secretive transmissions or documents. Persons or organizations that do not possess the appropriate decryption key to decrypt an encrypted file must result to a battery of cryptological techniques to decrypt files, even using artificial cognitive computation sources as powerful as "smart" AIs.

The sender will encrypt a piece and send it to the receiver, and will list both the public key and private key of the file. The public key is widely available, and was used to encrypt the file. The private key is available only to the receiver, and is used to decrypt the file.

The Covenant and the United Nations Space Command both use encryption devices to hide military tactics and orders.

Covenant usage
The Covenant occasionally place advanced encryption on high-importance locked doors within their warships, such as the CCS-class battlecruiser Truth and Reconciliation. During the UNSC raid on the battlecruiser, the Covenant locked the UNSC assault squad in the hangar bays with 128,000-bit modulating encryption until Cortana was able to hack the doors to open and let the UNSC forces venture further into the ship.

UNSC usage
Encryption is placed on UNSC documentation or transmissions in order to maintain the level of secrecy demanded by the Transmission Classification. Encryption codes, like classifications, come in varying types, based on the importance of the information in the file.

Encryption keys

 * None - Transmissions without code are not classified at all and can be accessed by anyone at any time. Examples of this include the journals produced by UNSC Astrophysics, such as UNSC Astrophysics Journal 034-23-01.


 * Red - This code is used most of the time in military transmissions. Classification can be "Restricted," "Classified," or "Secret". The code is sometimes harder to crack, depending on how complex the scheme of the code can be. Examples of this code include the Cole Protocol. It was used before or during 2552 to encrypt UNSC Emergency Priority Order 098831A-1.


 * Black - This higher level code is used for more important and urgent information, which can be classified.


 * Gamma - This is one of the highest level codes. It is used on the most classified information and is likely to be an extremely complex code. It coincided with the classification of "Eyes Only Top Secret."


 * Gamma-Shift-X-Ray - This is a code used to encrypt files. It was used to encrypt Historical/Psychological Analysis of Cole, Preston J..


 * Umber - This is a code used to encrypt files. It was used to encrypt files related to 92738-61842-LC's investigations regarding the Guardian incident in 2558.

Red

 * file/albatross-seven-lucifer-zeno/
 * file/bravo-tango-beta-five/
 * file/douglas-six-six-lima/
 * file/excised access Omega/
 * file/first light/
 * file/lightning-matrix-four/
 * file/vegas-anaconda-mockingbird-zero/

Black

 * file/delta-charlie-niner/Iona
 * file/gamma-thunder-twelve
 * file/rho-hotel-eight/Iona
 * file/seasonal/
 * file/zulu-oscar-papa/Iona

Gamma

 * user/bmorad

Unknown

 * file/red rover red rover/

Transmissions
Below is a list of transmissions sent that were encrypted by encryption codes:

None

 * UNSC Astrophysics Journal 034-23-01 (DIMENSIONAL-MASS SPACE COMPRESSIONS IN SHAW-FUJIKAWA (A.K.A "SLIPSTREAM") SPACE)

Red

 * UNITED NATIONS SPACE COMMAND ALPHA PRIORITY TRANSMISSION 04592Z-83 (IMMEDIATE RECALL)


 * UNITED NATIONS SPACE COMMAND TRANSMISSION 08871D-00 (TROUBLE)


 * UNITED NATIONS SPACE COMMAND PRIORITY TRANSMISSION 09872H-98 (MITIGATING FACTORS AND RELATIVE BIOLOGICAL RISKS ASSOCIATED WITH QUERIED EXPERIMENTAL MEDIAL PROCEDURES)


 * UNITED NATIONS SPACE COMMAND PRIORITY TRANSMISSION 09872H-98 (ORDERS FOR YOUR CONSIDERATION)


 * UNITED NATIONS SPACE COMMAND EMERGENCY PRIORITY ORDER 098831A-1 (GENERAL ORDER 098831A-1 (“THE COLE PROTOCOL”))


 * UNITED NATIONS SPACE COMMAND TRANSMISSION 102482-02 (SAFEGUARDING NAVIGATION DATA – MORE THOUGHTS)


 * UNITED NATIONS SPACE COMMAND TRANSMISSION 116749-09 (REQUISITIONS, TRANSFERS, AND FAVORS)


 * UNITED NATIONS SPACE COMMAND TRANSMISSION 34670J-17 (READINESS)

Black

 * UNITED NATIONS SPACE COMMAND PRIORITY TRANSMISSION 90872H-11 (OPERATION BLOWBACK)
 * UNITED NATIONS SPACE COMMAND PRIORITY TRANSMISSION FLASH 91762P-06 (EMERGENCY ALERT STATUS)

Gamma

 * PLNB TRANSMISSION XX087R-XX (Historical/Psychological Analysis of Cole, Preston J.)
 * PLNB TRANSMISSION XX087R-XX (PROGRESS REPORT/OPERATION HYPODERMIC)
 * PLNB TRANSMISSION XX219C-XX (INVESTIGATION UPDATE/OPERATION: BLEACH)

Unknown
Public Key: Red Rover Red Rover

List of appearances

 * Halo: The Fall of Reach
 * Adjunct
 * Halo: Combat Evolved
 * Halo: Combat Evolved Anniversary
 * Halo: Ghosts of Onyx
 * Halo: Blood Line
 * Halo: Evolutions - Essential Tales of the Halo Universe
 * The Impossible Life and the Possible Death of Preston J. Cole