QR Code Generator

Package otp implements both HOTP and TOTP based one time passcodes in a Google Authenticator compatible manner. When adding a TOTP for a user, you must store the "secret" value persistently. It is recommend to store the secret in an encrypted field in your datastore. Due to how TOTP works, it is not possible to store a hash for the secret value like you would a password. To enroll a user, you must first generate an OTP for them. Google Authenticator supports using a QR code as an enrollment method: Validating a TOTP passcode is very easy, just prompt the user for a passcode and retrieve the associated user's previously stored secret.

Package qrcode implements a QR Code encoder. A QR Code is a matrix (two-dimensional) barcode. Arbitrary content may be encoded. A QR Code contains error recovery information to aid reading damaged or obscured codes. There are four levels of error recovery: qrcode.{Low, Medium, High, Highest}. QR Codes with a higher recovery level are more robust to damage, at the cost of being physically larger. Three functions cover most use cases: - Create a PNG image: - Create a PNG image and write to a file: - Create a PNG image with custom colors and write to file: All examples use the qrcode.Medium error Recovery Level and create a fixed 256x256px size QR Code. The last function creates a white on black instead of black on white QR Code. To generate a variable sized image instead, specify a negative size (in place of the 256 above), such as -4 or -5. Larger negative numbers create larger images: A size of -5 sets each module (QR Code "pixel") to be 5px wide/high. - Create a PNG image (variable size, with minimum white padding) and write to a file: The maximum capacity of a QR Code varies according to the content encoded and the error recovery level. The maximum capacity is 2,953 bytes, 4,296 alphanumeric characters, 7,089 numeric digits, or a combination of these. This package implements a subset of QR Code 2005, as defined in ISO/IEC 18004:2006.

Package qrcode implements a QR Code encoder. A QR Code is a matrix (two-dimensional) barcode. Arbitrary content may be encoded. A QR Code contains error recovery information to aid reading damaged or obscured codes. There are four levels of error recovery: qrcode.{Low, Medium, High, Highest}. QR Codes with a higher recovery level are more robust to damage, at the cost of being physically larger. Three functions cover most use cases: - Create a PNG image: - Create a PNG image and write to a file: - Create a PNG image with custom colors and write to file: All examples use the qrcode.Medium error Recovery Level and create a fixed 256x256px size QR Code. The last function creates a white on black instead of black on white QR Code. To generate a variable sized image instead, specify a negative size (in place of the 256 above), such as -4 or -5. Larger negative numbers create larger images: A size of -5 sets each module (QR Code "pixel") to be 5px wide/high. - Create a PNG image (variable size, with minimum white padding) and write to a file: The maximum capacity of a QR Code varies according to the content encoded and the error recovery level. The maximum capacity is 2,953 bytes, 4,296 alphanumeric characters, 7,089 numeric digits, or a combination of these. This package implements a subset of QR Code 2005, as defined in ISO/IEC 18004:2006.

Package twofactor implements the RFC 6238 TOTP: Time-Based One-Time Password Algorithm The library provides a simple and secure way to generate and verify the OTP tokens and provides the possibility to display QR codes out of the box The library supports HMAC-SHA1, HMAC-SHA256, HMAC-SHA512

The otp package provides an opinionated way to generate and verify TOTP tokens as well as providing an easy way to encrypt the secrets for persistent storage (e.g., in the database alongside user records). It also provides a facility to dump QR codes to the terminal so that they can be scanned by an authenticator application.

Package qrcode implements a QR Code encoder. A QR Code is a matrix (two-dimensional) barcode. Arbitrary content may be encoded. A QR Code contains error recovery information to aid reading damaged or obscured codes. There are four levels of error recovery: qrcode.{Low, Medium, High, Highest}. QR Codes with a higher recovery level are more robust to damage, at the cost of being physically larger. Three functions cover most use cases: - Create a PNG image: - Create a PNG image and write to a file: - Create a PNG image with custom colors and write to file: All examples use the qrcode.Medium error Recovery Level and create a fixed 256x256px size QR Code. The last function creates a white on black instead of black on white QR Code. To generate a variable sized image instead, specify a negative size (in place of the 256 above), such as -4 or -5. Larger negative numbers create larger images: A size of -5 sets each module (QR Code "pixel") to be 5px wide/high. - Create a PNG image (variable size, with minimum white padding) and write to a file: The maximum capacity of a QR Code varies according to the content encoded and the error recovery level. The maximum capacity is 2,953 bytes, 4,296 alphanumeric characters, 7,089 numeric digits, or a combination of these. This package implements a subset of QR Code 2005, as defined in ISO/IEC 18004:2006.

Package for creating QR codes for payments. Short Payment Descriptor format and EPC QR Code (SEPA) format is supported. - Generating QR code image for Short Payment Descriptor format - Generating QR code image for EPC QR Code QR code image encoding uses https://github.com/skip2/go-qrcode - Getting QR code content for Short Payment Descriptor format

Package otp implements both HOTP and TOTP based one time passcodes in a Google Authenticator compatible manner. When adding a TOTP for a user, you must store the "secret" value persistently. It is recommended to store the secret in an encrypted field in your datastore. Due to how TOTP works, it is not possible to store a hash for the secret value like you would a password. To enroll a user, you must first generate an OTP for them. Google Authenticator supports using a QR code as an enrollment method: Validating a TOTP passcode is very easy, just prompt the user for a passcode and retrieve the associated user's previously stored secret.

Package qrcode implements a QR Code encoder. A QR Code is a matrix (two-dimensional) barcode. Arbitrary content may be encoded. A QR Code contains error recovery information to aid reading damaged or obscured codes. There are four levels of error recovery: qrcode.{Low, Medium, High, Highest}. QR Codes with a higher recovery level are more robust to damage, at the cost of being physically larger. Three functions cover most use cases: - Create a PNG image: - Create a PNG image and write to a file: - Create a PNG image with custom colors and write to file: All examples use the qrcode.Medium error Recovery Level and create a fixed 256x256px size QR Code. The last function creates a white on black instead of black on white QR Code. To generate a variable sized image instead, specify a negative size (in place of the 256 above), such as -4 or -5. Larger negative numbers create larger images: A size of -5 sets each module (QR Code "pixel") to be 5px wide/high. - Create a PNG image (variable size, with minimum white padding) and write to a file: The maximum capacity of a QR Code varies according to the content encoded and the error recovery level. The maximum capacity is 2,953 bytes, 4,296 alphanumeric characters, 7,089 numeric digits, or a combination of these. This package implements a subset of QR Code 2005, as defined in ISO/IEC 18004:2006.

Package otp implements both HOTP and TOTP based one time passcodes in a Google Authenticator compatible manner. When adding a TOTP for a user, you must store the "secret" value persistently. It is recommended to store the secret in an encrypted field in your datastore. Due to how TOTP works, it is not possible to store a hash for the secret value like you would a password. To enroll a user, you must first generate an OTP for them. Google Authenticator supports using a QR code as an enrollment method: Validating a TOTP passcode is very easy, just prompt the user for a passcode and retrieve the associated user's previously stored secret.