Key escrow
Encyclopedia
Key escrow is an arrangement in which the keys needed to decrypt encrypted
data are held in escrow
so that, under certain circumstances, an authorized third party may gain access to those keys. These third parties may include businesses, who may want access to employees' private communications, or governments, who may wish to be able to view the contents of encrypted communications.
The technical problem is a largely structural one since access to protected information must be provided only to the intended recipient and at least one third party. The third party should be permitted access only under carefully controlled conditions, as for instance, a court order
. Thus far, no system design has been shown to meet this requirement fully on a technical basis alone. All proposed systems also require correct functioning of some social linkage, as for instance the process of request for access, examination of request for 'legitimacy' (as by a court), and granting of access by technical personnel charged with access control. All such linkages / controls have serious problems from a system design security perspective.
On a national level, this is controversial
in many countries due to technical mistrust of the security of the escrow arrangement (due to a long history of less than adequate protection of others' information by assorted organizations, public and private, even when the information is held only under an affirmative legal obligation to protect it from unauthorized access), and to a mistrust of the entire system even if it functions as designed. Thus far, no key escrow system has been designed which meets both objections and nearly all have failed to meet even one.
Key escrow is proactive, anticipating the need for access to keys; a retroactive alternative is key disclosure law
, where users are required to surrender keys upon demand by law enforcement, or else face legal penalties. Key disclosure law avoids some of the technical issues and risks of key escrow systems, but also introduces new risks like loss of keys. The ambiguous term key recovery is applied to both types of systems.
----
Encryption
In cryptography, encryption is the process of transforming information using an algorithm to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information...
data are held in escrow
Escrow
An escrow is:* an arrangement made under contractual provisions between transacting parties, whereby an independent trusted third party receives and disburses money and/or documents for the transacting parties, with the timing of such disbursement by the third party dependent on the fulfillment of...
so that, under certain circumstances, an authorized third party may gain access to those keys. These third parties may include businesses, who may want access to employees' private communications, or governments, who may wish to be able to view the contents of encrypted communications.
The technical problem is a largely structural one since access to protected information must be provided only to the intended recipient and at least one third party. The third party should be permitted access only under carefully controlled conditions, as for instance, a court order
Court order
A court order is an official proclamation by a judge that defines the legal relationships between the parties to a hearing, a trial, an appeal or other court proceedings. Such ruling requires or authorizes the carrying out of certain steps by one or more parties to a case...
. Thus far, no system design has been shown to meet this requirement fully on a technical basis alone. All proposed systems also require correct functioning of some social linkage, as for instance the process of request for access, examination of request for 'legitimacy' (as by a court), and granting of access by technical personnel charged with access control. All such linkages / controls have serious problems from a system design security perspective.
On a national level, this is controversial
Controversy
Controversy is a state of prolonged public dispute or debate, usually concerning a matter of opinion. The word was coined from the Latin controversia, as a composite of controversus – "turned in an opposite direction," from contra – "against" – and vertere – to turn, or versus , hence, "to turn...
in many countries due to technical mistrust of the security of the escrow arrangement (due to a long history of less than adequate protection of others' information by assorted organizations, public and private, even when the information is held only under an affirmative legal obligation to protect it from unauthorized access), and to a mistrust of the entire system even if it functions as designed. Thus far, no key escrow system has been designed which meets both objections and nearly all have failed to meet even one.
Key escrow is proactive, anticipating the need for access to keys; a retroactive alternative is key disclosure law
Key disclosure law
Key disclosure laws, also known as mandatory key disclosure, is legislation that require individuals to surrender cryptographic keys to law enforcement. The purpose is to allow access to material for confiscation or digital forensics purposes and use it either as evidence in a court of law or to...
, where users are required to surrender keys upon demand by law enforcement, or else face legal penalties. Key disclosure law avoids some of the technical issues and risks of key escrow systems, but also introduces new risks like loss of keys. The ambiguous term key recovery is applied to both types of systems.
See also
- CryptographyCryptographyCryptography is the practice and study of techniques for secure communication in the presence of third parties...
- Key managementKey managementKey management is the provisions made in a cryptography system design that are related to generation, exchange, storage, safeguarding, use, vetting, and replacement of keys. It includes cryptographic protocol design, key servers, user procedures, and other relevant protocols.Key management concerns...
- Clipper chipClipper chipThe Clipper chip was a chipset that was developed and promoted by the U.S. National Security Agency as an encryption device to be adopted by telecommunications companies for voice transmission...
- Data Securities InternationalData Securities InternationalData Securities International, DSI is a company based in San Francisco, California that escrows source code for licensees.-History:In 1981, mathematician Dwight Olson saw an opportunity in the infant software product industry. Software companies often were unpredictable and difficult-to-understand...
- Related Key AttacksRelated-key attackIn cryptography, a related-key attack is any form of cryptanalysis where the attacker can observe the operation of a cipher under several different keys whose values are initially unknown, but where some mathematical relationship connecting the keys is known to the attacker...
External links
- Bruce Schneier - The risks of key escrow
- Encryption Policy: Memo for the Vice President CIA memo to Al Gore on suggested US policy on key recovery, 11. September 1996
- Other Related Key AttacksRelated-key attackIn cryptography, a related-key attack is any form of cryptanalysis where the attacker can observe the operation of a cipher under several different keys whose values are initially unknown, but where some mathematical relationship connecting the keys is known to the attacker...
----