Table of Contents<\/p>
- Introduction<\/a><\/li>
- Detailed implementation<\/a><\/li>
- Using Apache common validation<\/a><\/li><\/ul><\/div>\n\n
Introduction<\/span><\/h2>\n
Luhn algorithm<\/code>, also known asmodulus 10<\/code> ormod 10<\/code> algorithm, is a simple checksum process for validating various identification numbers such as credit card numbers, Canadian social securities numbers.
\nThis algorithm is designed to protect again mistyped or accidental error rather than malicious attacks. Most credit card companies adopted this algorithm as this was available in the public domain and can be used by anyone.<\/p>\nHere are the steps involved in Luhn Algorithms.<\/p>\n
\nStep 1:<\/code><\/strong>
\nFrom the rightmost digit, we should double every second digit.<\/p>\n![\"LuhnAlgorithmMulBy2\"](\"https:\/\/java2blog.com\/wp-content\/uploads\/2020\/04\/LuhnAlgorithmMul2.jpg\")
<\/p>\n
\nStep 2:<\/code><\/strong>
\nWhen we double the digits and get product in double digits, then we should add digits of the product.<\/p>\n![\"LuhnAlgorithmSumDigits\"](\"https:\/\/java2blog.com\/wp-content\/uploads\/2020\/04\/LuhnAlgorithmSumD.jpg\")
<\/p>\n
\nStep 3:<\/code><\/strong>
\nCompute the sum of all the digits.<\/p>\n![\"\"](\"https:\/\/java2blog.com\/wp-content\/uploads\/2020\/04\/LuhnAlgorithmSumAllD.jpg\")
<\/p>\n
\nStep 4:<\/code><\/strong>
\nIf total sum is divisible by 10 i.e. total sum modulo 10 is 0, then number is valid else it is not valid.<\/p>\n![\"LuhnAlgorithmCheckValid\"](\"https:\/\/java2blog.com\/wp-content\/uploads\/2020\/04\/LuhnAlgorithmCheckVal.jpg\")
<\/p>\nAs
90 mod 10 is 0<\/code>, hence this is valid credit card number.<\/p>\nDetailed implementation<\/span><\/h2>\n
Let’s create java program to implement the Luhn algorithm.<\/p>\n
\n\npackage org.arpit.java2blog;\n\nimport java.util.Arrays;\n\npublic class LuhnAlgorithmMain {\n\n public static void main(String[] args) {\n\n String cardNumber=\"1358954993914435\";\n\n boolean validCreditCardNumber = isValidCreditCardNumber(cardNumber);\n\n if(validCreditCardNumber)\n {\n System.out.println(cardNumber+\" is valid as per luhn algorithm\");\n }\n else\n {\n System.out.println(cardNumber+\" is not valid as per luhn algorithm\");\n }\n }\n\n public static boolean isValidCreditCardNumber(String cardNumber)\n {\n \/\/ int array for processing the cardNumber\n int[] cardIntArray=new int[cardNumber.length()];\n\n for(int i=0;iOutput:<\/strong><\/p>\n
90
\n1358954993914435 is valid as per luhn algorithm<\/div>\nHere are the steps involved in above java program for luhn algorithm.<\/p>\n
\n- \n
- Convert a String
cardNumber<\/code> to int arraycardIntArray<\/code> for processing<\/li>\n- Iterate
cardIntArray<\/code> from rightmost side starting fromcardIntArray.length-2<\/code> with step ofi=i-2<\/code><\/li>\n- Mulitply digit by 2<\/li>\n
- If product is greater than 9, sum the product<\/li>\n
- Assign result back to
cardIntArray[i]<\/code><\/li>\n- Once the loop is over, compute sum of elements of
cardIntArray<\/code><\/li>\n- if
sum%10<\/code> is0<\/code> then credit card number is valid else not valid as per luhn algorithm<\/li>\n<\/ol>\n<\/div>\nUsing Apache common validation<\/span><\/h2>\n
In case, you don’t want to implement luhn algorithm you can use Apache common validation library and validate credit card number using
LuhnCheckDigit.LUHN_CHECK_DIGIT.isValid(creditCardNumber);<\/code><\/p>\nYou need to add following dependency to
pom.xml<\/code>.<\/p>\n\n<!-- https:\/\/mvnrepository.com\/artifact\/commons-validator\/commons-validator -->\n<dependency>\n<groupId>commons-validator<\/groupId>\n<artifactId>commons-validator<\/artifactId>\n<version>1.6<\/version>\n<\/dependency>\n<\/pre>\n
Let’s see with the help of example:<\/p>\n
package org.arpit.java2blog;\n\nimport org.apache.commons.validator.routines.checkdigit.LuhnCheckDigit;\n\npublic class LuhnAlgorithmApache {\n\n public static void main(String[] args) {\n\n String cardNumber=\"79927398713\";\n\n boolean validCreditCardNumber = isValidCreditCardNumberLuhn(cardNumber); \n\n if(validCreditCardNumber)\n {\n System.out.println(cardNumber+\" is valid as per luhn algorithm\");\n }\n else\n {\n System.out.println(cardNumber+\" is not valid as per luhn algorithm\");\n }\n }\n\n public static boolean isValidCreditCardNumberLuhn(String creditCardNumber)\n {\n return LuhnCheckDigit.LUHN_CHECK_DIGIT.isValid(creditCardNumber);\n }\n}\n\n<\/pre>\nOutput:<\/strong><\/p>\n
79927398713 is valid as per luhn algorithm<\/div>\nThat’s all about Luhn Algorithm in java<\/p>\n","protected":false},"excerpt":{"rendered":"
Table of ContentsIntroductionDetailed implementationUsing Apache common validation In this post, we will see about Luhn Algorithm in java Introduction Luhn algorithm, also known as modulus 10 or mod 10 algorithm, is a simple checksum process for validating various identification numbers such as credit card numbers, Canadian social securities numbers. This algorithm is designed to protect […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"_mi_skip_tracking":false},"categories":[218],"tags":[],"_links":{"self":[{"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/posts\/9580"}],"collection":[{"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/comments?post=9580"}],"version-history":[{"count":0,"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/posts\/9580\/revisions"}],"wp:attachment":[{"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/media?parent=9580"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/categories?post=9580"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/tags?post=9580"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
- Iterate
- Detailed implementation<\/a><\/li>