From Wikipedia, the free encyclopedia

A Social Insurance Number (SIN) is a number issued in Canada to administer various government programs. The SIN was created in 1964 to serve as a client account number in the administration of the Canada Pension Plan and Canada's varied employment insurance programs. In 1967, Revenue Canada (now the Canada Revenue Agency) started using the SIN for tax reporting purposes. SINs are issued by Human Resources and Skills Development Canada (previously Human Resources Development Canada).

The SIN is formatted as three groups of three digits (e.g., 123-456-789).

Through functionality creep, the SIN has become a de facto national identification number, much in the same way as the Social Security Number in the United States. However, unlike in the US, in Canada there are specific legislated purposes for which a SIN can be requested. Unless an organization can demonstrate that the reason they are asking for a person's SIN is specifically allowed by law, or that no alternative identifiers would suffice to complete the transaction, they cannot deny or refuse a product or service on the grounds of a refusal to provide a SIN. Examples of organizations that legitimately require an SIN include employers, banks and investment companies, and federal government agencies. Giving an SIN when applying for consumer credit, such as buying a car or electronics, or allowing it to be used as a general purpose identification number, such as by your cable company, is likely a bad idea.

Social Insurance Numbers that begin with the number "9" are issued to temporary residents who are not Canadian citizens (e.g., foreign students, individuals on work visas) or permanent residents. These individuals must have an employment authorization in order to work in Canada. SINs beginning with a "9" are different from SINs assigned to citizens and permanent residents, because they have an expiry date (which usually coincides with the expiration of the holder's work authorization). These SINs are invalid unless there is an expiry date listed on the card and the date has not passed.

Social Insurance Numbers can be validated through a simple check digit process called the Luhn Algorithm.

 046 454 286 <--- A fictitious, but valid SIN
 121 212 121 <--- Multiply each top number by the number below it.

The result is:

 086 858 276

Notice that, in the second-to-last column, 8 multiplied by 2 is equal to 16. In the case of a two-digit number, simply add the digits together (1 + 6) and insert the result (in this case, 7). When writing a program to complete this task, minus 9 might be simpler to implement (in this case 16 - 9 = 7).

Then, add all of the digits together:

 0+8+6+8+5+8+2+7+6=50

If the SIN is valid, this number will be evenly divisible by 10.

The first digit of a SIN indicates the province in which it was registered:

1: Atlantic Provinces: Nova Scotia, New Brunswick, Prince Edward Island, and Newfoundland and Labrador

2: Quebec

3: Quebec

4: Ontario (including overseas forces)

5: Ontario

6: Prairie Provinces (Manitoba, Saskatchewan, and Alberta), Northwest Territories, and Nunavut

7: Pacific Region (British Columbia and Yukon)

8: Not used

9: Temporary resident

0: Not used (Canada Revenue may assign fictitious SIN numbers beginning with zero to taxpayers which do not have SINs)

Note: While the first digit usually identifies the location of registration, the government has found it necessary in the past to supply certain regions with SIN numbers assigned to other regions.

• Social Insurance Number FAQ Page
• SIN Privacy FAQ, from the Office of the Privacy Commissioner of Canada
• Social Insurance Number Authentication
• Social Insurance Number Generator; Generates all possible SIN combinations for verification and possible future hacking applications