Base Encoding

Functions

	Name
int	Base64_Decode(const byte * in, word32 inLen, byte * out, word32 * outLen) This function decodes the given Base64 encoded input, in, and stores the result in the output buffer out. It also sets the size written to the output buffer in the variable outLen.
int	Base64_Encode(const byte * in, word32 inLen, byte * out, word32 * outLen) This function encodes the given input, in, and stores the Base64 encoded result in the output buffer out. It writes the data with the traditional ‘ ’ line endings, instead of escaped %0A line endings. Upon successfully completing, this function also sets outLen to the number of bytes written to the output buffer. If there is enough room in out to store an extra byte, a NULL terminator will be added. This will NOT be included in outLen.
int	Base64_EncodeEsc(const byte * in, word32 inLen, byte * out, word32 * outLen) This function encodes the given input, in, and stores the Base64 encoded result in the output buffer out. It writes the data with %0A escaped line endings instead of ‘ ’ line endings. Upon successfully completing, this function also sets outLen to the number of bytes written to the output buffer.
int	Base64_Encode_NoNl(const byte * in, word32 inLen, byte * out, word32 * outLen) This function encodes the given input, in, and stores the Base64 encoded result in the output buffer out. It writes the data with no new lines. Upon successfully completing, this function also sets outLen to the number of bytes written to the output buffer.
int	Base16_Decode(const byte * in, word32 inLen, byte * out, word32 * outLen) This function decodes the given Base16 encoded input, in, and stores the result in the output buffer out. It also sets the size written to the output buffer in the variable outLen.
int	Base16_Encode(const byte * in, word32 inLen, byte * out, word32 * outLen) Encode input to base16 output. If there is enough room in out to store an extra byte, a NULL terminator will be added and included in outLen.
int	Base64_Decode_nonCT(const byte * in, word32 inLen, byte * out, word32 * outLen) This function decodes Base64 encoded input without using constant-time operations. This is faster than the constant-time version but may be vulnerable to timing attacks. Use only when timing attacks are not a concern.

Functions Documentation

function Base64_Decode

int Base64_Decode(
    const byte * in,
    word32 inLen,
    byte * out,
    word32 * outLen
)

This function decodes the given Base64 encoded input, in, and stores the result in the output buffer out. It also sets the size written to the output buffer in the variable outLen.

Parameters:

• in pointer to the input buffer to decode
• inLen length of the input buffer to decode
• out pointer to the output buffer in which to store the decoded message
• outLen pointer to the length of the output buffer. Updated with the bytes written at the end of the function call

See:

• Base64_Encode
• Base16_Decode

Return:

• 0 Returned upon successfully decoding the Base64 encoded input
• BAD_FUNC_ARG Returned if the output buffer is too small to store the decoded input
• ASN_INPUT_E Returned if a character in the input buffer falls outside of the Base64 range ([A-Za-z0-9+/=]) or if there is an invalid line ending in the Base64 encoded input

Example

byte encoded[] = { // initialize text to decode };
byte decoded[sizeof(encoded)];
// requires at least (sizeof(encoded) * 3 + 3) / 4 room

int outLen = sizeof(decoded);

if( Base64_Decode(encoded,sizeof(encoded), decoded, &outLen) != 0 ) {
    // error decoding input buffer
}

function Base64_Encode

int Base64_Encode(
    const byte * in,
    word32 inLen,
    byte * out,
    word32 * outLen
)

This function encodes the given input, in, and stores the Base64 encoded result in the output buffer out. It writes the data with the traditional ‘ ’ line endings, instead of escaped %0A line endings. Upon successfully completing, this function also sets outLen to the number of bytes written to the output buffer. If there is enough room in out to store an extra byte, a NULL terminator will be added. This will NOT be included in outLen.

Parameters:

• in pointer to the input buffer to encode
• inLen length of the input buffer to encode
• out pointer to the output buffer in which to store the encoded message
• outLen pointer to the length of the output buffer in which to store the encoded message

See:

• Base64_EncodeEsc
• Base64_Decode

Return:

• 0 Returned upon successfully decoding the Base64 encoded input
• BAD_FUNC_ARG Returned if the output buffer is too small to store the encoded input
• BUFFER_E Returned if the output buffer runs out of room while encoding

Example

byte plain[] = { // initialize text to encode };
byte encoded[MAX_BUFFER_SIZE];

int outLen = sizeof(encoded);

if( Base64_Encode(plain, sizeof(plain), encoded, &outLen) != 0 ) {
    // error encoding input buffer
}

function Base64_EncodeEsc

int Base64_EncodeEsc(
    const byte * in,
    word32 inLen,
    byte * out,
    word32 * outLen
)

This function encodes the given input, in, and stores the Base64 encoded result in the output buffer out. It writes the data with %0A escaped line endings instead of ‘ ’ line endings. Upon successfully completing, this function also sets outLen to the number of bytes written to the output buffer.

Parameters:

• in pointer to the input buffer to encode
• inLen length of the input buffer to encode
• out pointer to the output buffer in which to store the encoded message
• outLen pointer to the length of the output buffer in which to store the encoded message

See:

• Base64_Encode
• Base64_Decode

Return:

• 0 Returned upon successfully decoding the Base64 encoded input
• BAD_FUNC_ARG Returned if the output buffer is too small to store the encoded input
• BUFFER_E Returned if the output buffer runs out of room while encoding
• ASN_INPUT_E Returned if there is an error processing the decode on the input message

Example

byte plain[] = { // initialize text to encode };
byte encoded[MAX_BUFFER_SIZE];

int outLen = sizeof(encoded);

if( Base64_EncodeEsc(plain, sizeof(plain), encoded, &outLen) != 0 ) {
    // error encoding input buffer
}

function Base64_Encode_NoNl

int Base64_Encode_NoNl(
    const byte * in,
    word32 inLen,
    byte * out,
    word32 * outLen
)

This function encodes the given input, in, and stores the Base64 encoded result in the output buffer out. It writes the data with no new lines. Upon successfully completing, this function also sets outLen to the number of bytes written to the output buffer.

Parameters:

• in pointer to the input buffer to encode
• inLen length of the input buffer to encode
• out pointer to the output buffer in which to store the encoded message
• outLen pointer to the length of the output buffer in which to store the encoded message

See:

• Base64_Encode
• Base64_Decode

Return:

• 0 Returned upon successfully decoding the Base64 encoded input
• BAD_FUNC_ARG Returned if the output buffer is too small to store the encoded input
• BUFFER_E Returned if the output buffer runs out of room while encoding
• ASN_INPUT_E Returned if there is an error processing the decode on the input message

Example

byte plain[] = { // initialize text to encode };
byte encoded[MAX_BUFFER_SIZE];
int outLen = sizeof(encoded);
if( Base64_Encode_NoNl(plain, sizeof(plain), encoded, &outLen) != 0 ) {
    // error encoding input buffer
}

function Base16_Decode

int Base16_Decode(
    const byte * in,
    word32 inLen,
    byte * out,
    word32 * outLen
)

This function decodes the given Base16 encoded input, in, and stores the result in the output buffer out. It also sets the size written to the output buffer in the variable outLen.

Parameters:

• in pointer to the input buffer to decode
• inLen length of the input buffer to decode
• out pointer to the output buffer in which to store the decoded message
• outLen pointer to the length of the output buffer. Updated with the bytes written at the end of the function call

See:

• Base64_Encode
• Base64_Decode
• Base16_Encode

Return:

• 0 Returned upon successfully decoding the Base16 encoded input
• BAD_FUNC_ARG Returned if the output buffer is too small to store the decoded input or if the input length is not a multiple of two
• ASN_INPUT_E Returned if a character in the input buffer falls outside of the Base16 range ([0-9A-F])

Example

byte encoded[] = { // initialize text to decode };
byte decoded[sizeof(encoded)];
int outLen = sizeof(decoded);

if( Base16_Decode(encoded,sizeof(encoded), decoded, &outLen) != 0 ) {
    // error decoding input buffer
}

function Base16_Encode

int Base16_Encode(
    const byte * in,
    word32 inLen,
    byte * out,
    word32 * outLen
)

Encode input to base16 output. If there is enough room in out to store an extra byte, a NULL terminator will be added and included in outLen.

Parameters:

• in Pointer to input buffer to be encoded.
• inLen Length of input buffer.
• out Pointer to output buffer.
• outLen Length of output buffer. Is set to len of encoded output.

See:

• Base64_Encode
• Base64_Decode
• Base16_Decode

Return:

• 0 Success
• BAD_FUNC_ARG Returns if in, out, or outLen is null or if outLen is less than 2 times inLen plus 1.

Example

byte in[] = { // Contents of something to be encoded };
byte out[NECESSARY_OUTPUT_SIZE];
word32 outSz = sizeof(out);

if(Base16_Encode(in, sizeof(in), out, &outSz) != 0)
{
    // Handle encode error
}

function Base64_Decode_nonCT

int Base64_Decode_nonCT(
    const byte * in,
    word32 inLen,
    byte * out,
    word32 * outLen
)

This function decodes Base64 encoded input without using constant-time operations. This is faster than the constant-time version but may be vulnerable to timing attacks. Use only when timing attacks are not a concern.

Parameters:

• in pointer to the input buffer to decode
• inLen length of the input buffer to decode
• out pointer to the output buffer to store decoded message
• outLen pointer to length of output buffer; updated with bytes written

See:

• Base64_Decode
• Base64_Encode

Return:

• 0 On successfully decoding the Base64 encoded input.
• BAD_FUNC_ARG If the output buffer is too small to store the decoded input.
• ASN_INPUT_E If a character in the input buffer falls outside of the Base64 range or if there is an invalid line ending.
• BUFFER_E If running out of buffer while decoding.

Example

byte encoded[] = "SGVsbG8gV29ybGQ="; // "Hello World" in Base64
byte decoded[64];
word32 outLen = sizeof(decoded);

int ret = Base64_Decode_nonCT(encoded, sizeof(encoded)-1, decoded,
                               &outLen);
if (ret != 0) {
    // error decoding input
}
// decoded now contains "Hello World"

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Updated on 2025-12-31 at 01:16:02 +0000